Research ArticleExtracts and Fractions from Edible Roots of Sechium edule(Jacq) Sw with Antihypertensive Activity

Galia Lombardo-Earl12 Rubeacuten Roman-Ramos1

Alejandro Zamilpa2 Maribel Herrera-Ruiz2 Gabriela Rosas-Salgado3

Jaime Tortoriello2 and Enrique Jimeacutenez-Ferrer2

1 Programa de Doctorado en Ciencias Biologicas y de la Salud Division de Ciencias Biologicas y de la SaludUniversidad Autonoma Metropolitana Iztapalapa 09340 Mexico DF Mexico

2 Centro de Investigacion Biomedica del Sur (CIBIS-IMSS) Argentina 1 Colonia Centro 62790 Xochitepec MOR Mexico3 Facultad de Medicina Universidad Autonoma del Estado de Morelos Calle Iztaccihuatl Esq Leneros SN Colonia Volcanes62350 Cuernavaca MOR Mexico

Correspondence should be addressed to Enrique Jimenez-Ferrer enriqueferrer mxyahoocom

Received 2 September 2013 Revised 2 March 2014 Accepted 11 March 2014 Published 9 April 2014

Academic Editor Jose Luis Rıos

Copyright copy 2014 Galia Lombardo-Earl et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Sechium edule is traditionally used in Mexico as a therapeutic resource against renal diseases and to control high blood pressureThe purpose of this work is to evaluate the antihypertensive effect of the hydroalcoholic extract obtained from the roots of this plantincluding its fractions and subfractions on different hypertension models induced with angiotensin II (AG II)The hydroalcoholicextract was tested on an in vitro study of isolated aorta rings denuded of endothelial cells usingAG II as the agonist this assay provedthe vasorelaxant effect of this extract Vagotomized rats were administered different doses of AG II as well as the Hydroalcoholicextract which reduced blood pressure in 30mmHg approximately subsequently this extract was separated into two fractions(acetone and methanol) which were evaluated in the acute hypertension mouse model induced with AG II where the acetonefraction was identified as the most effective one and was subsequently subfractioned using an open chromatographic columnpacked with silica gel The subfractions were also evaluated in the acute hypertension model Finally the extract fraction andactive subfraction were analyzed by MS-PDA-HPLC identifying cinnamic derivative compounds like cinnamic acid methyl ester

1 Introduction

Sechium edule (Jacq) Sw (Cucurbitaceae) is an endemic plantfromMexico known as chayote It is originally from southernMexico (states of Veracruz Puebla and Oaxaca) and wasdomesticated in the valleys of Oaxaca and Tehuacan Puebla[1] S edule is cultivated for alimentary purposes where thestems and fruits are mainly used although the roots arespecially appreciated in the east and southeast of Mexico [2]The roots are described as a succulent fibrous tuber witha characteristic flavour [3] Also this plant is used in theMexican traditional medicine in Motozintla Chiapas theldquoMamrdquo indigenous community employs the chayote plant fortreating symptoms such as severe headaches with ringingears nervousness and anxiety where a decoction of the

leaves is prepared for use as drinking water throughoutthe day [4] Its use is also reported for the treatment ofrenal and urinary disorders like bladder or kidney stonesinflammation of the urethra and difficulty and pain whenurinating as well as high blood pressure varicose veins andvenous insufficiency among others [5 6]

There has been little pharmacological research done onS edule These studies have reported the hypotensive activityof aqueous and hydroalcoholic extracts from aerial partsof the plant the treatments were administered orally andintraperitoneally in rats and dogs respectively [7 8] Otherreports have indicated that the hydroalcoholic extract offruits of two varieties of S edule which were administeredintravenously in anaesthetized rats produced effects ondifferent cardiovascular parameters such as lowering blood

Hindawi Publishing CorporationEvidence-Based Complementary and Alternative MedicineVolume 2014 Article ID 594326 9 pageshttpdxdoiorg1011552014594326

2 Evidence-Based Complementary and Alternative Medicine

pressure and displaying changes on electrocardiographic(ECG) recordings [9] Nonetheless the action mechanismsby which these extracts act are not described Phytochemicalanalysis has been done on the hydroalcoholic extracts of rootsand aerial parts of S edule plants collected in Italy wherechemical differences between the two plant organs werereported The aerial parts contained a high concentrationof luteolin glycosides while the most significant concentra-tion of apigenin derivatives (C-glycosidic and O-glycosidicbonds) was found in the root extract [10] The aim of thecurrent study was to evaluate the antihypertensive effect ofS edule root extract and fractions on two different murinemodels in which the participation of the extracts as a calciumantagonist is proposed as well as the possible modulation ofAG II together with the chemical identification of the activecompounds implicated in the pharmacological activity

2 Materials and Methods

21 Plant Material and Extract Preparation Sechium edule(Jacq) Sw roots and aerial parts were collected in thecommunity of Tuxpanguillo Veracruz Mexico (18∘47101584000510158401015840N and 97∘00101584017510158401015840W 1721 meters above mean sea level)during the months of April and May Plant material wasidentified byAbigail Aguilar-ContrerasMS and the IMSSMHerbarium Director (located in National Medical CenterMexico City) Voucher specimens were stored for futurereference (IMSSM-15549) The roots (R) were dehydratedby freeze-drying and ground in an electric mill (Pulvex)obtaining particles of lt4mm An exhaustive maceration wasconducted with ethanolwater (60 40) mix at room temper-ature concentrated by evaporation at reduced pressure andcontrolled temperature and finally dried by lyophilizationobtaining a hydroalcoholic root extract (SeRHA) After apharmacological evaluation of this extract on vagotomizedrats it was submitted to a prechemical separation with ace-tone following with methanol obtaining the acetone extract(SeRAce) and the methanol extract (SeRMeOH)

Based on the results obtained from the acute pharmaco-logical evaluation SeRAce (2 g) was then subjected to chem-ical separation by a chromatographic column (64 times 5 cm)packed with Silica-Gel 60 Merck (0040ndash0063mm) The col-umn was eluted against a gradient of chloroform methanolForty-one fractions were obtained which then were analysedby thin layer chromatography (silica gel on aluminium sheets60 F245 Merck) Based on their chromatographic profile20 fractions were grouped and named R1 to R20 fromthese fractions the eight most representative ones wereevaluated on the acute hypertension mice model and twowere characterized by HPLC using HPLC module system(Waters 2595) coupled with a PDA detector (Waters 996)and Empower Chromatographic Manager software version1 empower pro (Waters) The stationary phase correspondedto a column Altima HP C18-HL Rocket (53 times 7mm 3 120583m)The mobile phase consisted of a gradient (Table 1) of 05TFA CH

3CN 1 1 at a rate flow of 1mLmin for 24min using

a photodiode detector array the wavelengths were scannedat 250ndash600 nm and the main compounds were analyzed at340 nm for flavonoids and at 290 nm for cinnamic derivatives

Table 1 Process conditions for HPLC chromatographic characteri-zation of the extracts of S edule

Time (min) Flow 05 TFA () CH3CN ()0 100 1000 00100 100 1000 00200 100 900 100400 100 900 100500 100 800 200700 100 800 200800 100 700 3001400 100 700 3001500 100 600 4001800 100 600 4001900 100 200 8002200 100 200 8002300 100 00 10002600 100 00 10002700 100 1000 002800 100 1000 00

The extracts and fractions were also analysed by MS-PDA-HPLC to identify the molecular weight of the activecompounds The method used was as follows for theHPLC analysis liquid chromatographer (Agilent 1200) witha visible-UV diode array detector (Waters model 2996) wasused with a column Zorbax Eclipse Plus C18 100 times 21mm35 120583m The eluent used was acetonitrile and water02acetic acid starting at 10 90 and at 30min 90 10 respec-tively The temperature for the column was 40∘C with aflow rate of 02mLmin the results were read at 300 nmMS was performed on an Esquire 6000 operating withnegative ion polarity ESI ionization mode and negativecurrent alternating ion

22 Animals Male Sprague-Dawley albino rats (250ndash280 g)and male ICR albino mice (30ndash36 g) from Harlan MexicoCity were used All animals were housed (8 per cage) andmaintained under laboratory conditions 25∘C a normal12 h 12 h lightdark schedule (lights on at 0700 am) withfree access to water and food (pellets from Harlan rodentlab diet) The animals were given at least three weeks toadapt to the laboratory environment before experimentsAll studies were carried out in accordance with the officialMexican regulation NOM-062-ZOO-1999 (technical specifi-cations for production care and use of laboratory animals)the experimental protocol including the ethical aspects wasauthorized since December 14 2010 by the Local HealthResearch Committee (IMSS Registry number R-2010-1701-62)

23 Angiotensin II Induced Hypertension in VagotomizedRats Rats were put under surgical anaesthesia with ure-thane (15 gkg ip) the cervical vagus nerve was cut andthe femoral vein was dissected in order to allow drugadministration Blood pressure (BP) was measured thoughtindirect blood pressure equipment (LE 5002 Storage Pressure

Evidence-Based Complementary and Alternative Medicine 3

Meter Biopac Systems MP 150) In all animals hexametho-nium chloride (ganglion-blocking agent) was administeredat 01 gkg iv dose After BP stabilization increasing dosagesof AG II (05 1 and 2120583gkg) were administered to establisha dose dependent curve BP was recorded every 20 s for8min following each dose After recording the baseline bloodpressure three doses of SeRHA were administered (50 100and 200mgkg op) One hour later BP was measured for aperiod of 5min immediately AG II was injected iv at thedoses previously given and BP was measured again

24 Acute Hypertension Induced on Mice with AG II Basedon the acute high blood pressuremodel proposed by Jimenez-Ferrer et al (2010) [11] to establish an acute model ofhypertension on mice it was necessary to determine whichdose of AG II was enough to elevate SBP and DBP over thenormal parameters (12070mmHg) A dose dependent curvewas done (data not shown) The optimal dose defined was1 120583gkg of AG II (Sigma) by iv administration Subsequentlya bioguided analysis was performed to define which extract(SeRHA SeRAce or SeRMeOH 50mgkg op) exhibiteda higher antihypertensive activity The three extracts wereadministered by op one hour prior to the trial as wellas Losartan (10mgkg op) an AT

1receptor antagonist of

AG II that was used as the positive control The experimentcontrol group received isotonic saline solution (100 120583L10 gop) One hour after the treatments under surgical anaes-thesia (pentobarbital 55120583gkg ip) BP was monitored by anoninvasive BP detector (LE 5002 Storage Pressure MeterBiopac SystemsMP150) 8 BP lectures were taken to establisha base line immediately after AG II was administered andthe BP was registered again At this point the SeRAce extractwas chosen for the chemical separation by chromatographiccolumn Representative fractions (R2 R5 R6 R8 R11 R14R17 and R20) were also tested in this same model

25 In Vitro Aorta Ring Assay Rats were sacrificed by decap-itation the thoracic aorta was isolated cleaned of fat andconnective tissue and all aortas were denuded of endothe-lium film by gentle mechanical procedure and finally cutinto rings of about 4-5mm of width The rings were tiedto stainless steel hooks with silk thread and immersed into10mL organ baths of Krebs solution at 37∘C and oxygenated(O2CO2 95 5) A basal tension of 2 g was established for

all tissues and Biopac Systems TSD 125c equipped withAcqKnowledge software recorded changes in basal tensionKCl (120mM) was administered to determine the maximumcontraction of each prepared aorta

Sixtymin after stabilizing the tissue ringswere stimulatedwith different concentrations of AG II (from 100 times 10minus10 to100 times 10

minus6M) for 10min and then washed out to removestimulant agent and stabilized for another 30minThe tissueswere preincubated with SeRHA (150 120583gmL 300 120583gmL and600120583gmL) respectively The relaxant effect was determinedby comparison amongmaximum vascular contraction beforeand after addition of samples

To determine the possible vasorelaxant mechanism (likecalcium antagonism) It was evaluate the effect of calcium

Table 2 Effect produced on systolic and diastolic blood pressure ofvagotomized rats by the administration of angiotensin II (iv)

AG II doses120583gkg iv

Systolic pressuremmHg plusmn SD

Diastolic pressuremmHg plusmn SD

00 1277 plusmn 313 551 plusmn 32705 1443 plusmn 734lowast 7033 plusmn 615lowast

10 1456 plusmn 122lowast 783 plusmn 930lowast

20 15360 plusmn 110lowast 855 plusmn 154lowast

Data are presented as means plusmn SD with 119899 = 7 ANOVA and post hocBonferroni test lowast119875 lt 005 was compared to basal data (001mgkg AG II)

over AG II agonistic activity the assay consisted of evaluatinga calcium concentration curve inducing vasoconstrictionwith AG II at a specific concentration (1 times 10minus6M) and theactivity of SeRHA (200120583gmL 400 120583gmL and 800 120583gmL)Nifedipine (calcium channel blocker) was employed as posi-tive control

26 Statistical Analysis Statistical analysis was carried outwith SPSS 110 and based on an analysis of variance (ANOVA)followed by Bonferroni test A significant difference wasestablished with respect to control group when the 119875 valuewas lower than 005

3 Results

31 Effect of S edule Root Extract on Vagotomized Rats withAG II Induced Hypertension Blood pressure elevation onvagotomized rats was established by a dose dependent curveas showed in Table 2

The administration of the different dosages of SeRHAextract was capable of inhibiting the increment of BP whengiven the respective dose of AG II the effect of which waspreestablished in the dose dependent curve Figure 1 indicatesthe differential of the decrement of the systolic blood pressure(SBP) and diastolic blood pressure (DBP) when given AG IIOnce the highest dose of AG II (20120583gkg) is administeredin all three SeRHA treatments there is a proportional dropin BP In Figure 1(a) the 200mgkg dose of SeRHA showeda statistical difference when the 20 120583gkg AG II dose wasadministered decreasing BP in 30mmHg (119865(293) lt 5306119875 lt 005) when compared with differential effect (de)induced with the lower dose of AG II (05 120583gkg) and SeRHA(50mgkg) The behaviour of the hypotensive activity fromthe SeRHA 100 and 200mgkg dose was proportional to theadministration of the AG II dose making it a dose dependentdrop in SBP where BP dropped 24mmHg with a statisticaldifference of both groups of 119865(293) lt 15296 119875 lt 005when compared with differential effect (de) induced withthe lower dose of AG II (05 120583gkg) and SeRHA (50mgkg)This activity could be consistent with the modification of thecardiac output of the animals and this might be the cause whyLozoya et al [7 8] saw a modification on the ECG recordingswhen they tested the fruit and leaf extracts

The modification of DBP is shown in Figure 1(b) wherethe three dosages of SeRHA produced an important effect

4 Evidence-Based Complementary and Alternative Medicine

0

510

15

25

35

45

20

30

40

05 1 2

Systo

licΔP

(mm

Hg)

AGII treatment (120583gkg)

lowast

lowast

(a)

05 1 2

AGII treatment (120583gkg)

SeRHA 50mgkgSeRHA 100mgkgSeRHA 200mgkg

lowast

lowast

lowast lowast

lowastlowast

0

5

10

15

20

25

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35

Dia

stolicΔP

(mm

Hg)

(b)

Figure 1 Antihypertensive activity of increasing doses (50 100and 200mgkg ip) of SeRHA in vagotomized rats with ganglionblockage by hexamethonium chloride pretreated with AG II ivEach bar represents the average of the differential of systolic (a) anddiastolic (b) blood pressure with respect to the basal pressure afterAG II administration ANOVA post hoc Bonferroni lowast119875 lt 005when compared to SeRHA 50 mgkg represented in white bars (119899 =6 mean plusmn SE)

preventing an increase in DBP when administered the differ-ent AG II doses These results were more evident than thoseof SBP since only the 100 and 200mgkg doses of SeRHA thatwere administered in all three AG II groups showed the mostimportant hypotensive activity compared with the smallestdose of SeRHA and AG II that are exhibited as the whitebars as well as in the SBP results the highest dose of AG IIand of SeRHA had the most potent effect with a fall of DBPof around 25mmHg The impairment of the increment ofDBP by the SeRHA extract in this model might be associatedwith an AG II antagonist activity due to the nature of thismodel where one of the ways to block AG II effect wouldbe the extract interacting with the AT

1receptor for AG II

since the vagotomization and ganglionic blockage inhibit theBP control mechanisms in general and the model is inducedby intravenous injection of the agonistic AG II leaving thismechanism of action as the most prominent to occur

32 Ring Aorta Assay Figures 2 and 3 show the behaviourof the isolated rat aortas without endothelial cells under twoconditions of stimulation of vascular smooth muscle Theresulting contraction is reportedwith regard to themaximumcontraction produced by the administration of KCl

0

20

40

60

80

100

120

100E minus 10 100E minus 09 100E minus 08 100E minus 07 100E minus 06 100E minus 05

Con

trac

tion

with

KCl

()

AGII concentration (M)

AGIISeRHA 150120583gmL

SeRHA 300120583gmLSeRHA 600120583gmL

Figure 2 Percentages of the contraction of vascular smooth muscleof rat aorta rings stimulatedwith increasing concentrations of AG IIwith respect to themaximum effect obtained with KCl as well as theevaluation of the vasorelaxant effect of the SeRHAextract stimulatedwith AG II

Figure 2 presents the aorta contraction curve dependenton the increasing concentration of AG II (∙) with a 119864max =

98and aEC50= 85times10

minus9M It also shows the effect of threedoses of SeRHA + AG II 150 120583gmL () 300 120583gmL (◻) and600120583gmL (times) all three extracts had a statistical differencewith respect to AG II where the first concentration of SeRHAhad a decrease of 14 of 119864max the second one of 44 of 119864maxand the highest concentration diminished the contraction66 of 119864max The EC

50values for the three concentrations of

SeRHA were with an average of 15 times 10minus8MFigure 3 shows the Ca++ concentration curve stimulated

with a constant concentration of AG II (1 times 10minus6M) (∙) Thecontraction of the aorta was dependent on Ca++ concentra-tion The AG II 119864max value was 98 of contraction with anEC50= 00008M When SeRHA + AG II was administered

the resulting effect had a statistically significant decreaseof 119864max where SeRHA of 200120583gmL () decreased 20400 120583gmL (◻) decreased 48 and finally the 800 120583gmL (times)concentrations produced a 69 contraction of the aorta withrespect to AG II by itself the values of EC

50obtained were of

0003M in average In this experiment Nifedipine was usedas a positive control due to its calcium channel blocker effect

33 Bioguided Fractioning of SeRHA Using the Acute Hyper-tension Mice Model Induced with AG II Having establishedthe hypotensive activity of the SeRHA extract it is importantto identify which group of compounds is responsible for thebiological activity The extract was summited to a chemi-cal separation and two fractions SeRAce and SeRMeOHextracts were obtainedThe oral administration of the extractand fractions was able to reduce the blood pressure whileadministering AG II (10 120583gkg iv) (Figure 4) The mostactive fraction was SeRAce and the complete extract SeRHAshown by statistical differences for SBP of 119865(257) lt 3969119875 lt 005 and for DBP of 119865(257) lt 12676 119875 lt 005

Evidence-Based Complementary and Alternative Medicine 5

0

20

40

60

80

100

120

000001 00001 0001 001 01 1

Con

trac

tion

with

KCl

()

Concentration CaCl2 (M)

AGII SeRHA 200120583gmLSeRHA 400120583gmLSeRHA 800120583gmLNifedipine 30nM

Nifedipine 15nM

Figure 3 Percentages of the contraction of vascular smoothmuscle of rat aorta rings stimulated with AG II in presence ofincreasing concentrations of CaCl

2

with respect to the maximumeffect obtained with KCl as well as the modulating effect of SeRHAextract on the contraction Nifedipine was used as a positive controldue to its calcium channel blocker activity

Table 3 Antihypertensive effect produced by losartan (10mgkg)and fractions (50mgkg) obtained from SeRAce on pretreated micewith AG II (10120583gkg iv )

Treatment Systolic BP mmHg Diastolic BP mmHgVehicle 12751 plusmn 324 6114 plusmn 674AG II 14640 plusmn 301 9590 plusmn 801R2 13398 plusmn 1586 863 plusmn 1486R5 12261 plusmn 1643 845 plusmn 1808R6 13238 plusmn 1787 9303 plusmn 2083R8 13801 plusmn 1484 9363 plusmn 1398R11 11945 plusmn 1985 8207 plusmn 1623R14 10921 plusmn 1394lowast 6888 plusmn 1210lowast

R17 10909 plusmn 873lowast 7166 plusmn 1453lowast

R20 12255 plusmn 1315 7771 plusmn 1097Losartan 11950 plusmn 1173 7745 plusmn 1241Data are presented as means plusmn SD with 119899 = 7 ANOVA and post hocBonferroni test lowast119875 lt 005 is with respect to the negative control (AG II10 120583gkg)

when compared to the negative control condition (AG II)with a critical decrease of SBP below the base line valueswas established by the vehicle (ISS) group Both Losartan andSeRMeOH did not achieve significant differences in SBP andDBP compared with SeRHA and SeRAce Nevertheless theylowered the BP when compared with the AG II group

331 Antihypertensive Activity of SeRAce Fractions Basedon the pharmacological activity of SeRAce extract it wasselected for chemical separation by chromatographic columnfrom which eight fractions (R2 R5 R6 R8 R11 R14 R17andR20)were chosen based on their chromatographic profileto be evaluated on the acute hypertension mice model(Table 3) Five of the eight fractions presented a decrease

0

20

40

60

80

100

120

140

160

Vehicle AGII SeRHA SeRAce SeRMeOH Losartan

Systo

lic b

lood

pre

ssur

e (m

mH

g)

Treatments

lowastlowast

(a)

Dia

stolic

blo

od p

ress

ure (

mm

Hg)

0

20

40

60

80

100

120

Vehicle AGII SeRHA SeRAce SeRMeOH LosartanTreatments

lowastlowast

(b)

Figure 4 Bioguided assay of S edule extracts against AG II agonisticeffect ANOVA post hoc Bonferroni lowast119875 lt 005 when compared tothe vehicle represented in white bars (119899 = 6 mean plusmn SE)

in BP when administered AG II all five fractions had asignificant hypotensive activity on SBP although not all ofthem had the same activity on DBP Only two fractions (R14and R17) were able to significantly decrease SBP (119865(211) lt9292 119875 lt 005) and DBP (119865(211) lt 4118 119875 lt 005) witha net effect below the SBP of the ISS group and of the controlgroup Losartan The hypotensive activity of these extractsand fractions could be related to the phenolic compoundsthat were identified in the chemical characterization donethrough HPLC of the R14 and R17 fractions and SeRHA aswell as for SeRAce extracts

34 Chemical Analysis SeRHA SeRAce and the most activefractions (R14 and R17) were analysed by HPLC and MS-PDA-HPLC the compounds in each one displayed diverseUV spectra that can be related to flavones (120582max = 340 nm)and cinnamic acid derivatives (120582max = 290 nm)

The extraction made with acetone from SeRHA allowedus to obtain a less polar fraction that also presented theantihypertensive activity that was tested in the biologicalmodel used

The chromatographic comparison of SeRHA extract withthe fraction SeRAcet that was read at 340 nm (specific forvitexin and other related flavonoids) (Figure 5(a)) allowsobserving the loss of this type of compounds in the fractionSeRAcet as well as the more polar compounds that came outwith the solvent front When the comparison of these two

6 Evidence-Based Complementary and Alternative Medicine

200 600 1000 1400 1800 2200 2600

(min)

0000

0020

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0060

0080

(AU

)

(a)

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(min)

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(AU

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(b)

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(min)

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2099

2239

3077

39704186

43794693

4838

50085275

5420

5566

5919

(nm)

(AU

)

(e)

Figure 5 Chromatograms of SeRHA extract (blue line) compared with SeRAcet (black line) they were read at two length waves panel (a) at290 nm and panel (b) at 340 nm Fractions R14 (black line) and R17 (blue line) represented in panels (c) and (d) read at 340 nm and 290 nmrespectively show two peaks (1 and 2) with retention times of 721 and 804min Peak 2 corresponds to the cinnamic acid methyl ester thatcorresponds to the MS-PDA-HPLC analysis represented in Figure 6(a) peak 4 and Figure 6(b) peak 1603

was analysed at 290 nm (Figure 5(b)) It can be appreciatedan increment in the concentration of the peaks presentthroughout minute 7 to 18 of the retention times of thisfraction The chemical separation of these fraction derived20 fractions from which two of them R14 and R17 (at adose of 50mgkg) presented significant statistical differencein the biological activity superior to LosartanThese fractionswere compared in the chromatographic method at 290 nmobserving an increment in the peaks with retention time 721and 804min in both fractions having the sameUV spectrumfor both retention times peak 1 and 2 from Figures 5(c) and5(d) respectively TheMS-PDA-HPLC analysis from SeRHAand the Fraction 14 (Figure 6(a)) allowed establishing that

the peak with retention time of 108min corresponds to acinnamic acid methyl ester

4 Discussion

Blood pressure is a mechanism that an organism has tomaintain a constant irrigation of blood for nutrient distri-bution and oxygenation of organs and tissues It is regulatedessentially throughout two factors cardiac output (CO) andtotal peripheral resistance (TPR)The CO is the total amountof blood pumped in to the aorta each minute by the heartand the TPR or vascular resistance is the impediment toblood flow in a vessel The pharmacological model used in

Evidence-Based Complementary and Alternative Medicine 7

0 2 4 6 8 10 12 14 16 18

Time (min)

02040608

times104

Inte

nsity

12

3

4 5

(a)

100 200 300 400

mz

0

500

1000

1500

1603 1972

Ext00372d minusMS 107ndash109min 100 = 1359

3763

Inte

nsity

(b)

Figure 6 Mass chromatogram of fraction R14 (a) and its massabsorption spectrum (b)

this work has the purpose of simulating an alteration in theTPR increasing blood pressure by the administration of AGII and triggering a general vasoconstriction reaction Drugdiscovery [12] describes this assay as an AG II antagonismmodel

The vagotomization of the rats eliminates the cardio-vascular reflexes without interfering with the heart rateand normal blood pressure allowing AG II to induce anincrease of blood pressure inciting an acute vasoconstrictionwhen administered intravenously without any interventionof the sympathetic and parasympathetic response whichare responsible for the immediate homeostatic control ofblood pressure The ganglionic-blockade purpose is to blockthe transmission of nerve impulses through the autonomicganglia [13] impairing the vasculature to compensate bloodpressure when administered AG II or the extract evaluated

The results obtained from this model allowed us notonly to confirm the antihypertensive effect of this plantbut also to identify the probable action mechanism Theextracts of S edule may have an AG II antagonism activityThis action mechanism can be modulated through directantagonism of the AG II receptor AT

1or by the intervention

on calciumfluxes activated byAG II impeding the immediatevasoconstriction response to the iv administration of AG II

In the isolated aorta assay AG II vasoconstriction actionwas dependent on Ca++ concentration where it was observedthat the increment in Ca++ promoted a rise of the contractionof the aorta when a single concentration of AG II wasadministered Nifedipine was used as a pharmacologicalcontrol it specifically blocks L-type calcium channels as acompetitive antagonist [14] on the calcium influx that canbe through depolarization or by receptor-response coupling[15] which in this assay was triggered by AG II The SeRHA

extract in comparison to Nifedipine responded as an irre-versible antagonist (also called pharmacologic antagonist)that shifts the dose-response curve downward indicating thatthe agonist can no longer exertmaximal effect at any dose Allthree concentrations of the extract that were tested not onlyinhibited the aorta contraction but also altered the EC

50as a

competitive antagonist would do [16]This behaviour confirms the AG II antagonist effect

although it could also have a calcium antagonist effectThe activity of SeRHA extract can be associated with anAG II receptor blocking action as well as obstructing thesecondmessenger system initiated by AG II which promotesthe efflux of sarcoplasmic calcium that activates the storeoperated channels (SOC) that allows more calcium to enterthe cell and form a calcium-calmodulin complex That endsin vascular contraction [17 18]

With these results the antihypertensive and vasorelaxantactivity of S edule root extract were demonstrated thereforea chemical separation was carried out obtaining a firstfraction SeRAce whichwas summited to chemical separationand the most chemically relevant fractions obtained wereanalysed on the acute hypertensive model two of them hadthe most pharmacological activity (R14 and R17) and werethen analysed by HPLC as well as SeRHA and SeRAce Thechemical results allowed us to identify most polyphenoliccompounds like flavonoids and phenylpropanoids Vitexinwas identified in SeRHA and SeRAce as well as coumaric andcinnamic acid in contrast with the extracts fractions R14 andR17 predominantly had coumaric and cinnamic acid Thisinformation is relevant and consistent to the results obtainedfrom the pharmacological experiments

Polyphenolic compounds have a very wide and importantbiological activity regarding cardiovascular diseases Mainlyin the regulation of high blood pressure recent studies areevoked on inflammation and ROS scavenging properties ofthis type of compounds [19ndash22]Thus there have been studieson flavonoids and cinnamic acid derivative on their calciumantagonism and vasorelaxant activity [23 24]

Liew et al [25] demonstrated that red wine polyphenolslike resveratrol act as calcium channel antagonists loweringfree intracellular Ca++ Summanen et al [23] presented thatnumerous simple phenolic compounds like cinnamic acidderivatives and flavonoids have a potent inhibition of Ca++entry by highK+-evoked activity the effects were comparableto those of verapamil They presented an inhibitory activityagainst Ca++ entry similar to the one of another classof natural Ca++ channel antagonists like furanocoumarinsidentified by Vuorela et al [26] Other studies of extracts ofGentiana floribunda that contained flavonoids and tanninsamong other compounds were effective for lowering bloodpressurewith a vasorelaxant effectmediated by the inhibitionof Ca++ influx via membranous calcium channels and itsrelease from the intracellular stores [27]

The presence of cinnamic acid derivatives in the Sedule extracts and fractions could be responsible for theangiotensin II and calcium antagonist effect which wereestablished with the pharmacological assays which aredesigned to identify a specific action mechanism Cinnamicacid derivatives are a group of natural compounds that have

8 Evidence-Based Complementary and Alternative Medicine

been studied in different antihypertensive models mostly asanti-inflammatory and antioxidant activity although thesestudies are based on chronic hypertension assays whichoriginate by the alterations of Ca++ fluxes in the vascularsmooth muscle and on the reninmdashangiotensinmdashaldosteronesystem

5 Conclusions

In conclusion the results obtained in this work demonstratethat S edule extracts have an antihypertensive activity whichis consistentwith the traditional use inMexicoThus the phy-tochemical analysis was not precise on a specific compoundand the richness in polyphenols opens a new range of inquiryfor other action mechanisms of S edule extracts related toinflammation and oxidative stress damage that is related tohypertension and endothelial dysfunction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was partially supported by CONACyT Mexico(SNI3229152834-M) IMSSMexico (FISIMSSPROT348)and CONACyT Mexico (Salud113632) Grants This paperis taken in part from the PhD of Galia Lombardo Earl(Programa de Doctorado en Ciencias Biologicas y de laSalud) belonging to the Universidad Autonoma Metropoli-tana (UAM) with a Doctoral fellowship from CONACyTMexico (Registry no 208601202091)

References

[1] H Pipitone Oaxaca Prehispanica CIDE (Centro de Inves-tigacion y Docencia Economica) Mexico DF Mexico 1stedition 2006

[2] SAGARPA ldquoBrevesmonografias agrıcolasrdquo 2005 httpw4siapsagarpagobmxAppEstadomonografiasHortalizasChayotehtml

[3] C Monroy-Ortiz and P Castillo-Espana Plantas MedicinalesUtilizadas en el Estado de Morelos UAEM-CONABIO Cuer-navaca Morelos Mexico 2nd edition 2007

[4] Biblioteca Digital de la Medicina Tradicional httpwwwmedicinatradicionalmexicanaunammxflora2phpl=4amppo=mamampte=Chayoteampid=6407ampclave region=34

[5] V A Argueta ldquoSechium edulerdquo in Atlas de las Plantas de laMedicina Tradicional Mexicana A L Cano and M E RodarteEds pp 393ndash394 Instituto Nacional Indigenista Biblioteca dela Medicina Tradicional Mexicana Mexico DF Mexico 1994

[6] R Lira J Castrejon S Zamudio and C Rojas-ZentenoldquoPropuesta de ubicacion taxonomica para los chayotes silvestres(Sechium edule Cucurbitaceae) de Mexicordquo Acta BotanicaMexicana vol 49 pp 47ndash61 1999

[7] X Lozoya ldquoMexican medicinal plants used for treatment ofcardiovascular diseasesrdquoAmerican Journal of Chinese Medicinevol 8 no 1-2 pp 86ndash95 1980

[8] A R de Ribeiro M Fiuza and F de Barros ldquoAcute antihy-pertensive effect in conscious rats produced by some medicinalplants used in the state of Sao Paulordquo Journal of Ethnopharma-cology vol 15 no 3 pp 261ndash269 1986

[9] E AGordon L J Guppy andMNelson ldquoThe antihypertensiveeffects of the Jamaican Cho-Cho (Sechium edule)rdquo The WestIndian Medical Journal vol 49 no 1 pp 27ndash31 2000

[10] T Siciliano N de Tommasi I Morelli and A Braca ldquoStudyof flavonoids of Sechium edule (Jacq) Swartz (Cucurbitaceae)different edible organs by liquid chromatography photodiodearray mass spectrometryrdquo Journal of Agricultural and FoodChemistry vol 52 no 21 pp 6510ndash6515 2004

[11] E Jimenez-Ferrer FHernandez BadilloMGonzalez-CortazarJ Tortoriello and M Herrera-Ruiz ldquoAntihypertensive activ-ity of Salvia elegans Vahl (Lamiaceae) ACE inhibition andangiotensin II antagonismrdquo Journal of Ethnopharmacology vol130 no 2 pp 340ndash346 2010

[12] H G Vogel Drug Discovery and Evaluation PharmacologicalAssays Springer 2nd edition 2002

[13] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition p 760 2006

[14] J-B Shen B Jiang and A J Pappano ldquoComparison of L-typecalcium channel blockade by nifedipine andor cadmium inguinea pig ventricular myocytesrdquo The Journal of Pharmacologyand Experimental Therapeutics vol 294 no 2 pp 562ndash5702000

[15] T Godfraind ldquoActions of nifedipine on calcium fluxes andcontraction in isolated rat arteriesrdquoThe Journal of Pharmacologyand Experimental Therapeutics vol 224 no 2 pp 443ndash4501983

[16] C J Weir ldquoIon channels receptors agonists and antagonistsrdquoAnaesthesia amp Intensive Care Medicine vol 11 no 9 pp 377ndash383 2010

[17] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition pp 914ndash915 2006

[18] A B Parekh and J W Putney Jr ldquoStore-operated calciumchannelsrdquo Physiological Reviews vol 85 no 2 pp 757ndash8102005

[19] T Schewe Y Steffen and H Sies ldquoHow do dietary flavanolsimprove vascular function A position paperrdquo Archives ofBiochemistry and Biophysics vol 476 no 2 pp 102ndash106 2008

[20] D K Maurya and T P A Devasagayam ldquoAntioxidant andprooxidant nature of hydroxycinnamic acid derivatives ferulicand caffeic acidsrdquo Food and Chemical Toxicology vol 48 no 12pp 3369ndash3373 2010

[21] Y Lee D-H Shin J-H Kim et al ldquoCaffeic acid phenethylester-mediated Nrf2 activation and I120581B kinase inhibition areinvolved in NF120581B inhibitory effect structural analysis for NF120581Binhibitionrdquo European Journal of Pharmacology vol 643 no 1pp 21ndash28 2010

[22] J Chen X Chen Y Lei et al ldquoVascular protective potential ofthe total flavanol glycosides from Abacopteris penangiana viamodulating nuclear transcription factor-120581B signaling pathwayand oxidative stressrdquo Journal of Ethnopharmacology vol 136 no1 pp 217ndash223 2011

[23] J Summanen P Vuorela J-P Rauha et al ldquoEffects of simplearomatic compounds and flavonoids on Ca2+ fluxes in ratpituitary GH

4

C1

cellsrdquo European Journal of Pharmacology vol414 no 2-3 pp 125ndash133 2001

[24] Y Zhang Y Cao Q Wang L Zheng J Zhang and L He ldquoApotential calcium antagonist and its antihypertensive effectsrdquoFitoterapia vol 82 no 7 pp 988ndash996 2011

Evidence-Based Complementary and Alternative Medicine 5

0

20

40

60

80

100

120

000001 00001 0001 001 01 1

Con

trac

tion

with

KCl

()

Concentration CaCl2 (M)

AGII SeRHA 200120583gmLSeRHA 400120583gmLSeRHA 800120583gmLNifedipine 30nM

Nifedipine 15nM

Figure 3 Percentages of the contraction of vascular smoothmuscle of rat aorta rings stimulated with AG II in presence ofincreasing concentrations of CaCl

2

with respect to the maximumeffect obtained with KCl as well as the modulating effect of SeRHAextract on the contraction Nifedipine was used as a positive controldue to its calcium channel blocker activity

Table 3 Antihypertensive effect produced by losartan (10mgkg)and fractions (50mgkg) obtained from SeRAce on pretreated micewith AG II (10120583gkg iv )

Treatment Systolic BP mmHg Diastolic BP mmHgVehicle 12751 plusmn 324 6114 plusmn 674AG II 14640 plusmn 301 9590 plusmn 801R2 13398 plusmn 1586 863 plusmn 1486R5 12261 plusmn 1643 845 plusmn 1808R6 13238 plusmn 1787 9303 plusmn 2083R8 13801 plusmn 1484 9363 plusmn 1398R11 11945 plusmn 1985 8207 plusmn 1623R14 10921 plusmn 1394lowast 6888 plusmn 1210lowast

R17 10909 plusmn 873lowast 7166 plusmn 1453lowast

R20 12255 plusmn 1315 7771 plusmn 1097Losartan 11950 plusmn 1173 7745 plusmn 1241Data are presented as means plusmn SD with 119899 = 7 ANOVA and post hocBonferroni test lowast119875 lt 005 is with respect to the negative control (AG II10 120583gkg)

when compared to the negative control condition (AG II)with a critical decrease of SBP below the base line valueswas established by the vehicle (ISS) group Both Losartan andSeRMeOH did not achieve significant differences in SBP andDBP compared with SeRHA and SeRAce Nevertheless theylowered the BP when compared with the AG II group

331 Antihypertensive Activity of SeRAce Fractions Basedon the pharmacological activity of SeRAce extract it wasselected for chemical separation by chromatographic columnfrom which eight fractions (R2 R5 R6 R8 R11 R14 R17andR20)were chosen based on their chromatographic profileto be evaluated on the acute hypertension mice model(Table 3) Five of the eight fractions presented a decrease

0

20

40

60

80

100

120

140

160

Vehicle AGII SeRHA SeRAce SeRMeOH Losartan

Systo

lic b

lood

pre

ssur

e (m

mH

g)

Treatments

lowastlowast

(a)

Dia

stolic

blo

od p

ress

ure (

mm

Hg)

0

20

40

60

80

100

120

Vehicle AGII SeRHA SeRAce SeRMeOH LosartanTreatments

lowastlowast

(b)

Figure 4 Bioguided assay of S edule extracts against AG II agonisticeffect ANOVA post hoc Bonferroni lowast119875 lt 005 when compared tothe vehicle represented in white bars (119899 = 6 mean plusmn SE)

in BP when administered AG II all five fractions had asignificant hypotensive activity on SBP although not all ofthem had the same activity on DBP Only two fractions (R14and R17) were able to significantly decrease SBP (119865(211) lt9292 119875 lt 005) and DBP (119865(211) lt 4118 119875 lt 005) witha net effect below the SBP of the ISS group and of the controlgroup Losartan The hypotensive activity of these extractsand fractions could be related to the phenolic compoundsthat were identified in the chemical characterization donethrough HPLC of the R14 and R17 fractions and SeRHA aswell as for SeRAce extracts

34 Chemical Analysis SeRHA SeRAce and the most activefractions (R14 and R17) were analysed by HPLC and MS-PDA-HPLC the compounds in each one displayed diverseUV spectra that can be related to flavones (120582max = 340 nm)and cinnamic acid derivatives (120582max = 290 nm)

The extraction made with acetone from SeRHA allowedus to obtain a less polar fraction that also presented theantihypertensive activity that was tested in the biologicalmodel used

The chromatographic comparison of SeRHA extract withthe fraction SeRAcet that was read at 340 nm (specific forvitexin and other related flavonoids) (Figure 5(a)) allowsobserving the loss of this type of compounds in the fractionSeRAcet as well as the more polar compounds that came outwith the solvent front When the comparison of these two

6 Evidence-Based Complementary and Alternative Medicine

200 600 1000 1400 1800 2200 2600

(min)

0000

0020

0040

0060

0080

(AU

)

(a)

200 600 1000 1400 1800 2200 2600

(min)

000

004

008

012

016

(AU

)

(b)

200 600 1000 1400 1800 2200 2600

(min)

0000

0010

0020

0030

0040

1

2

(AU

)

(c)

200 600 1000 1400 1800 2200 2600

(min)

0000

0020

0040

0060

0080

0100

1

2

(AU

)

(d)

20000 25000 30000 35000 40000 45000 50000 55000

000

002

004

006

008

010

2099

2239

3077

39704186

43794693

4838

50085275

5420

5566

5919

(nm)

(AU

)

(e)

Figure 5 Chromatograms of SeRHA extract (blue line) compared with SeRAcet (black line) they were read at two length waves panel (a) at290 nm and panel (b) at 340 nm Fractions R14 (black line) and R17 (blue line) represented in panels (c) and (d) read at 340 nm and 290 nmrespectively show two peaks (1 and 2) with retention times of 721 and 804min Peak 2 corresponds to the cinnamic acid methyl ester thatcorresponds to the MS-PDA-HPLC analysis represented in Figure 6(a) peak 4 and Figure 6(b) peak 1603

was analysed at 290 nm (Figure 5(b)) It can be appreciatedan increment in the concentration of the peaks presentthroughout minute 7 to 18 of the retention times of thisfraction The chemical separation of these fraction derived20 fractions from which two of them R14 and R17 (at adose of 50mgkg) presented significant statistical differencein the biological activity superior to LosartanThese fractionswere compared in the chromatographic method at 290 nmobserving an increment in the peaks with retention time 721and 804min in both fractions having the sameUV spectrumfor both retention times peak 1 and 2 from Figures 5(c) and5(d) respectively TheMS-PDA-HPLC analysis from SeRHAand the Fraction 14 (Figure 6(a)) allowed establishing that

the peak with retention time of 108min corresponds to acinnamic acid methyl ester

4 Discussion

Blood pressure is a mechanism that an organism has tomaintain a constant irrigation of blood for nutrient distri-bution and oxygenation of organs and tissues It is regulatedessentially throughout two factors cardiac output (CO) andtotal peripheral resistance (TPR)The CO is the total amountof blood pumped in to the aorta each minute by the heartand the TPR or vascular resistance is the impediment toblood flow in a vessel The pharmacological model used in

Evidence-Based Complementary and Alternative Medicine 7

0 2 4 6 8 10 12 14 16 18

Time (min)

02040608

times104

Inte

nsity

12

3

4 5

(a)

100 200 300 400

mz

0

500

1000

1500

1603 1972

Ext00372d minusMS 107ndash109min 100 = 1359

3763

Inte

nsity

(b)

Figure 6 Mass chromatogram of fraction R14 (a) and its massabsorption spectrum (b)

this work has the purpose of simulating an alteration in theTPR increasing blood pressure by the administration of AGII and triggering a general vasoconstriction reaction Drugdiscovery [12] describes this assay as an AG II antagonismmodel

The vagotomization of the rats eliminates the cardio-vascular reflexes without interfering with the heart rateand normal blood pressure allowing AG II to induce anincrease of blood pressure inciting an acute vasoconstrictionwhen administered intravenously without any interventionof the sympathetic and parasympathetic response whichare responsible for the immediate homeostatic control ofblood pressure The ganglionic-blockade purpose is to blockthe transmission of nerve impulses through the autonomicganglia [13] impairing the vasculature to compensate bloodpressure when administered AG II or the extract evaluated

The results obtained from this model allowed us notonly to confirm the antihypertensive effect of this plantbut also to identify the probable action mechanism Theextracts of S edule may have an AG II antagonism activityThis action mechanism can be modulated through directantagonism of the AG II receptor AT

1or by the intervention

on calciumfluxes activated byAG II impeding the immediatevasoconstriction response to the iv administration of AG II

In the isolated aorta assay AG II vasoconstriction actionwas dependent on Ca++ concentration where it was observedthat the increment in Ca++ promoted a rise of the contractionof the aorta when a single concentration of AG II wasadministered Nifedipine was used as a pharmacologicalcontrol it specifically blocks L-type calcium channels as acompetitive antagonist [14] on the calcium influx that canbe through depolarization or by receptor-response coupling[15] which in this assay was triggered by AG II The SeRHA

extract in comparison to Nifedipine responded as an irre-versible antagonist (also called pharmacologic antagonist)that shifts the dose-response curve downward indicating thatthe agonist can no longer exertmaximal effect at any dose Allthree concentrations of the extract that were tested not onlyinhibited the aorta contraction but also altered the EC

50as a

competitive antagonist would do [16]This behaviour confirms the AG II antagonist effect

although it could also have a calcium antagonist effectThe activity of SeRHA extract can be associated with anAG II receptor blocking action as well as obstructing thesecondmessenger system initiated by AG II which promotesthe efflux of sarcoplasmic calcium that activates the storeoperated channels (SOC) that allows more calcium to enterthe cell and form a calcium-calmodulin complex That endsin vascular contraction [17 18]

With these results the antihypertensive and vasorelaxantactivity of S edule root extract were demonstrated thereforea chemical separation was carried out obtaining a firstfraction SeRAce whichwas summited to chemical separationand the most chemically relevant fractions obtained wereanalysed on the acute hypertensive model two of them hadthe most pharmacological activity (R14 and R17) and werethen analysed by HPLC as well as SeRHA and SeRAce Thechemical results allowed us to identify most polyphenoliccompounds like flavonoids and phenylpropanoids Vitexinwas identified in SeRHA and SeRAce as well as coumaric andcinnamic acid in contrast with the extracts fractions R14 andR17 predominantly had coumaric and cinnamic acid Thisinformation is relevant and consistent to the results obtainedfrom the pharmacological experiments

Polyphenolic compounds have a very wide and importantbiological activity regarding cardiovascular diseases Mainlyin the regulation of high blood pressure recent studies areevoked on inflammation and ROS scavenging properties ofthis type of compounds [19ndash22]Thus there have been studieson flavonoids and cinnamic acid derivative on their calciumantagonism and vasorelaxant activity [23 24]

Liew et al [25] demonstrated that red wine polyphenolslike resveratrol act as calcium channel antagonists loweringfree intracellular Ca++ Summanen et al [23] presented thatnumerous simple phenolic compounds like cinnamic acidderivatives and flavonoids have a potent inhibition of Ca++entry by highK+-evoked activity the effects were comparableto those of verapamil They presented an inhibitory activityagainst Ca++ entry similar to the one of another classof natural Ca++ channel antagonists like furanocoumarinsidentified by Vuorela et al [26] Other studies of extracts ofGentiana floribunda that contained flavonoids and tanninsamong other compounds were effective for lowering bloodpressurewith a vasorelaxant effectmediated by the inhibitionof Ca++ influx via membranous calcium channels and itsrelease from the intracellular stores [27]

The presence of cinnamic acid derivatives in the Sedule extracts and fractions could be responsible for theangiotensin II and calcium antagonist effect which wereestablished with the pharmacological assays which aredesigned to identify a specific action mechanism Cinnamicacid derivatives are a group of natural compounds that have

8 Evidence-Based Complementary and Alternative Medicine

been studied in different antihypertensive models mostly asanti-inflammatory and antioxidant activity although thesestudies are based on chronic hypertension assays whichoriginate by the alterations of Ca++ fluxes in the vascularsmooth muscle and on the reninmdashangiotensinmdashaldosteronesystem

5 Conclusions

In conclusion the results obtained in this work demonstratethat S edule extracts have an antihypertensive activity whichis consistentwith the traditional use inMexicoThus the phy-tochemical analysis was not precise on a specific compoundand the richness in polyphenols opens a new range of inquiryfor other action mechanisms of S edule extracts related toinflammation and oxidative stress damage that is related tohypertension and endothelial dysfunction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was partially supported by CONACyT Mexico(SNI3229152834-M) IMSSMexico (FISIMSSPROT348)and CONACyT Mexico (Salud113632) Grants This paperis taken in part from the PhD of Galia Lombardo Earl(Programa de Doctorado en Ciencias Biologicas y de laSalud) belonging to the Universidad Autonoma Metropoli-tana (UAM) with a Doctoral fellowship from CONACyTMexico (Registry no 208601202091)

References

[1] H Pipitone Oaxaca Prehispanica CIDE (Centro de Inves-tigacion y Docencia Economica) Mexico DF Mexico 1stedition 2006

[2] SAGARPA ldquoBrevesmonografias agrıcolasrdquo 2005 httpw4siapsagarpagobmxAppEstadomonografiasHortalizasChayotehtml

[3] C Monroy-Ortiz and P Castillo-Espana Plantas MedicinalesUtilizadas en el Estado de Morelos UAEM-CONABIO Cuer-navaca Morelos Mexico 2nd edition 2007

[4] Biblioteca Digital de la Medicina Tradicional httpwwwmedicinatradicionalmexicanaunammxflora2phpl=4amppo=mamampte=Chayoteampid=6407ampclave region=34

[5] V A Argueta ldquoSechium edulerdquo in Atlas de las Plantas de laMedicina Tradicional Mexicana A L Cano and M E RodarteEds pp 393ndash394 Instituto Nacional Indigenista Biblioteca dela Medicina Tradicional Mexicana Mexico DF Mexico 1994

[6] R Lira J Castrejon S Zamudio and C Rojas-ZentenoldquoPropuesta de ubicacion taxonomica para los chayotes silvestres(Sechium edule Cucurbitaceae) de Mexicordquo Acta BotanicaMexicana vol 49 pp 47ndash61 1999

[7] X Lozoya ldquoMexican medicinal plants used for treatment ofcardiovascular diseasesrdquoAmerican Journal of Chinese Medicinevol 8 no 1-2 pp 86ndash95 1980

[8] A R de Ribeiro M Fiuza and F de Barros ldquoAcute antihy-pertensive effect in conscious rats produced by some medicinalplants used in the state of Sao Paulordquo Journal of Ethnopharma-cology vol 15 no 3 pp 261ndash269 1986

[9] E AGordon L J Guppy andMNelson ldquoThe antihypertensiveeffects of the Jamaican Cho-Cho (Sechium edule)rdquo The WestIndian Medical Journal vol 49 no 1 pp 27ndash31 2000

[10] T Siciliano N de Tommasi I Morelli and A Braca ldquoStudyof flavonoids of Sechium edule (Jacq) Swartz (Cucurbitaceae)different edible organs by liquid chromatography photodiodearray mass spectrometryrdquo Journal of Agricultural and FoodChemistry vol 52 no 21 pp 6510ndash6515 2004

[11] E Jimenez-Ferrer FHernandez BadilloMGonzalez-CortazarJ Tortoriello and M Herrera-Ruiz ldquoAntihypertensive activ-ity of Salvia elegans Vahl (Lamiaceae) ACE inhibition andangiotensin II antagonismrdquo Journal of Ethnopharmacology vol130 no 2 pp 340ndash346 2010

[12] H G Vogel Drug Discovery and Evaluation PharmacologicalAssays Springer 2nd edition 2002

[13] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition p 760 2006

[14] J-B Shen B Jiang and A J Pappano ldquoComparison of L-typecalcium channel blockade by nifedipine andor cadmium inguinea pig ventricular myocytesrdquo The Journal of Pharmacologyand Experimental Therapeutics vol 294 no 2 pp 562ndash5702000

[15] T Godfraind ldquoActions of nifedipine on calcium fluxes andcontraction in isolated rat arteriesrdquoThe Journal of Pharmacologyand Experimental Therapeutics vol 224 no 2 pp 443ndash4501983

[16] C J Weir ldquoIon channels receptors agonists and antagonistsrdquoAnaesthesia amp Intensive Care Medicine vol 11 no 9 pp 377ndash383 2010

[17] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition pp 914ndash915 2006

[18] A B Parekh and J W Putney Jr ldquoStore-operated calciumchannelsrdquo Physiological Reviews vol 85 no 2 pp 757ndash8102005

[19] T Schewe Y Steffen and H Sies ldquoHow do dietary flavanolsimprove vascular function A position paperrdquo Archives ofBiochemistry and Biophysics vol 476 no 2 pp 102ndash106 2008

[20] D K Maurya and T P A Devasagayam ldquoAntioxidant andprooxidant nature of hydroxycinnamic acid derivatives ferulicand caffeic acidsrdquo Food and Chemical Toxicology vol 48 no 12pp 3369ndash3373 2010

[21] Y Lee D-H Shin J-H Kim et al ldquoCaffeic acid phenethylester-mediated Nrf2 activation and I120581B kinase inhibition areinvolved in NF120581B inhibitory effect structural analysis for NF120581Binhibitionrdquo European Journal of Pharmacology vol 643 no 1pp 21ndash28 2010

[22] J Chen X Chen Y Lei et al ldquoVascular protective potential ofthe total flavanol glycosides from Abacopteris penangiana viamodulating nuclear transcription factor-120581B signaling pathwayand oxidative stressrdquo Journal of Ethnopharmacology vol 136 no1 pp 217ndash223 2011

[23] J Summanen P Vuorela J-P Rauha et al ldquoEffects of simplearomatic compounds and flavonoids on Ca2+ fluxes in ratpituitary GH

4

C1

cellsrdquo European Journal of Pharmacology vol414 no 2-3 pp 125ndash133 2001

[24] Y Zhang Y Cao Q Wang L Zheng J Zhang and L He ldquoApotential calcium antagonist and its antihypertensive effectsrdquoFitoterapia vol 82 no 7 pp 988ndash996 2011

6 Evidence-Based Complementary and Alternative Medicine

200 600 1000 1400 1800 2200 2600

(min)

0000

0020

0040

0060

0080

(AU

)

(a)

200 600 1000 1400 1800 2200 2600

(min)

000

004

008

012

016

(AU

)

(b)

200 600 1000 1400 1800 2200 2600

(min)

0000

0010

0020

0030

0040

1

2

(AU

)

(c)

200 600 1000 1400 1800 2200 2600

(min)

0000

0020

0040

0060

0080

0100

1

2

(AU

)

(d)

20000 25000 30000 35000 40000 45000 50000 55000

000

002

004

006

008

010

2099

2239

3077

39704186

43794693

4838

50085275

5420

5566

5919

(nm)

(AU

)

(e)

Figure 5 Chromatograms of SeRHA extract (blue line) compared with SeRAcet (black line) they were read at two length waves panel (a) at290 nm and panel (b) at 340 nm Fractions R14 (black line) and R17 (blue line) represented in panels (c) and (d) read at 340 nm and 290 nmrespectively show two peaks (1 and 2) with retention times of 721 and 804min Peak 2 corresponds to the cinnamic acid methyl ester thatcorresponds to the MS-PDA-HPLC analysis represented in Figure 6(a) peak 4 and Figure 6(b) peak 1603

was analysed at 290 nm (Figure 5(b)) It can be appreciatedan increment in the concentration of the peaks presentthroughout minute 7 to 18 of the retention times of thisfraction The chemical separation of these fraction derived20 fractions from which two of them R14 and R17 (at adose of 50mgkg) presented significant statistical differencein the biological activity superior to LosartanThese fractionswere compared in the chromatographic method at 290 nmobserving an increment in the peaks with retention time 721and 804min in both fractions having the sameUV spectrumfor both retention times peak 1 and 2 from Figures 5(c) and5(d) respectively TheMS-PDA-HPLC analysis from SeRHAand the Fraction 14 (Figure 6(a)) allowed establishing that

the peak with retention time of 108min corresponds to acinnamic acid methyl ester

4 Discussion

Blood pressure is a mechanism that an organism has tomaintain a constant irrigation of blood for nutrient distri-bution and oxygenation of organs and tissues It is regulatedessentially throughout two factors cardiac output (CO) andtotal peripheral resistance (TPR)The CO is the total amountof blood pumped in to the aorta each minute by the heartand the TPR or vascular resistance is the impediment toblood flow in a vessel The pharmacological model used in

Evidence-Based Complementary and Alternative Medicine 7

0 2 4 6 8 10 12 14 16 18

Time (min)

02040608

times104

Inte

nsity

12

3

4 5

(a)

100 200 300 400

mz

0

500

1000

1500

1603 1972

Ext00372d minusMS 107ndash109min 100 = 1359

3763

Inte

nsity

(b)

Figure 6 Mass chromatogram of fraction R14 (a) and its massabsorption spectrum (b)

this work has the purpose of simulating an alteration in theTPR increasing blood pressure by the administration of AGII and triggering a general vasoconstriction reaction Drugdiscovery [12] describes this assay as an AG II antagonismmodel

The vagotomization of the rats eliminates the cardio-vascular reflexes without interfering with the heart rateand normal blood pressure allowing AG II to induce anincrease of blood pressure inciting an acute vasoconstrictionwhen administered intravenously without any interventionof the sympathetic and parasympathetic response whichare responsible for the immediate homeostatic control ofblood pressure The ganglionic-blockade purpose is to blockthe transmission of nerve impulses through the autonomicganglia [13] impairing the vasculature to compensate bloodpressure when administered AG II or the extract evaluated

The results obtained from this model allowed us notonly to confirm the antihypertensive effect of this plantbut also to identify the probable action mechanism Theextracts of S edule may have an AG II antagonism activityThis action mechanism can be modulated through directantagonism of the AG II receptor AT

1or by the intervention

on calciumfluxes activated byAG II impeding the immediatevasoconstriction response to the iv administration of AG II

In the isolated aorta assay AG II vasoconstriction actionwas dependent on Ca++ concentration where it was observedthat the increment in Ca++ promoted a rise of the contractionof the aorta when a single concentration of AG II wasadministered Nifedipine was used as a pharmacologicalcontrol it specifically blocks L-type calcium channels as acompetitive antagonist [14] on the calcium influx that canbe through depolarization or by receptor-response coupling[15] which in this assay was triggered by AG II The SeRHA

extract in comparison to Nifedipine responded as an irre-versible antagonist (also called pharmacologic antagonist)that shifts the dose-response curve downward indicating thatthe agonist can no longer exertmaximal effect at any dose Allthree concentrations of the extract that were tested not onlyinhibited the aorta contraction but also altered the EC

50as a

competitive antagonist would do [16]This behaviour confirms the AG II antagonist effect

although it could also have a calcium antagonist effectThe activity of SeRHA extract can be associated with anAG II receptor blocking action as well as obstructing thesecondmessenger system initiated by AG II which promotesthe efflux of sarcoplasmic calcium that activates the storeoperated channels (SOC) that allows more calcium to enterthe cell and form a calcium-calmodulin complex That endsin vascular contraction [17 18]

With these results the antihypertensive and vasorelaxantactivity of S edule root extract were demonstrated thereforea chemical separation was carried out obtaining a firstfraction SeRAce whichwas summited to chemical separationand the most chemically relevant fractions obtained wereanalysed on the acute hypertensive model two of them hadthe most pharmacological activity (R14 and R17) and werethen analysed by HPLC as well as SeRHA and SeRAce Thechemical results allowed us to identify most polyphenoliccompounds like flavonoids and phenylpropanoids Vitexinwas identified in SeRHA and SeRAce as well as coumaric andcinnamic acid in contrast with the extracts fractions R14 andR17 predominantly had coumaric and cinnamic acid Thisinformation is relevant and consistent to the results obtainedfrom the pharmacological experiments

Polyphenolic compounds have a very wide and importantbiological activity regarding cardiovascular diseases Mainlyin the regulation of high blood pressure recent studies areevoked on inflammation and ROS scavenging properties ofthis type of compounds [19ndash22]Thus there have been studieson flavonoids and cinnamic acid derivative on their calciumantagonism and vasorelaxant activity [23 24]

Liew et al [25] demonstrated that red wine polyphenolslike resveratrol act as calcium channel antagonists loweringfree intracellular Ca++ Summanen et al [23] presented thatnumerous simple phenolic compounds like cinnamic acidderivatives and flavonoids have a potent inhibition of Ca++entry by highK+-evoked activity the effects were comparableto those of verapamil They presented an inhibitory activityagainst Ca++ entry similar to the one of another classof natural Ca++ channel antagonists like furanocoumarinsidentified by Vuorela et al [26] Other studies of extracts ofGentiana floribunda that contained flavonoids and tanninsamong other compounds were effective for lowering bloodpressurewith a vasorelaxant effectmediated by the inhibitionof Ca++ influx via membranous calcium channels and itsrelease from the intracellular stores [27]

The presence of cinnamic acid derivatives in the Sedule extracts and fractions could be responsible for theangiotensin II and calcium antagonist effect which wereestablished with the pharmacological assays which aredesigned to identify a specific action mechanism Cinnamicacid derivatives are a group of natural compounds that have

8 Evidence-Based Complementary and Alternative Medicine

been studied in different antihypertensive models mostly asanti-inflammatory and antioxidant activity although thesestudies are based on chronic hypertension assays whichoriginate by the alterations of Ca++ fluxes in the vascularsmooth muscle and on the reninmdashangiotensinmdashaldosteronesystem

5 Conclusions

In conclusion the results obtained in this work demonstratethat S edule extracts have an antihypertensive activity whichis consistentwith the traditional use inMexicoThus the phy-tochemical analysis was not precise on a specific compoundand the richness in polyphenols opens a new range of inquiryfor other action mechanisms of S edule extracts related toinflammation and oxidative stress damage that is related tohypertension and endothelial dysfunction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was partially supported by CONACyT Mexico(SNI3229152834-M) IMSSMexico (FISIMSSPROT348)and CONACyT Mexico (Salud113632) Grants This paperis taken in part from the PhD of Galia Lombardo Earl(Programa de Doctorado en Ciencias Biologicas y de laSalud) belonging to the Universidad Autonoma Metropoli-tana (UAM) with a Doctoral fellowship from CONACyTMexico (Registry no 208601202091)

References

[1] H Pipitone Oaxaca Prehispanica CIDE (Centro de Inves-tigacion y Docencia Economica) Mexico DF Mexico 1stedition 2006

[2] SAGARPA ldquoBrevesmonografias agrıcolasrdquo 2005 httpw4siapsagarpagobmxAppEstadomonografiasHortalizasChayotehtml

[3] C Monroy-Ortiz and P Castillo-Espana Plantas MedicinalesUtilizadas en el Estado de Morelos UAEM-CONABIO Cuer-navaca Morelos Mexico 2nd edition 2007

[4] Biblioteca Digital de la Medicina Tradicional httpwwwmedicinatradicionalmexicanaunammxflora2phpl=4amppo=mamampte=Chayoteampid=6407ampclave region=34

[5] V A Argueta ldquoSechium edulerdquo in Atlas de las Plantas de laMedicina Tradicional Mexicana A L Cano and M E RodarteEds pp 393ndash394 Instituto Nacional Indigenista Biblioteca dela Medicina Tradicional Mexicana Mexico DF Mexico 1994

[6] R Lira J Castrejon S Zamudio and C Rojas-ZentenoldquoPropuesta de ubicacion taxonomica para los chayotes silvestres(Sechium edule Cucurbitaceae) de Mexicordquo Acta BotanicaMexicana vol 49 pp 47ndash61 1999

[7] X Lozoya ldquoMexican medicinal plants used for treatment ofcardiovascular diseasesrdquoAmerican Journal of Chinese Medicinevol 8 no 1-2 pp 86ndash95 1980

[8] A R de Ribeiro M Fiuza and F de Barros ldquoAcute antihy-pertensive effect in conscious rats produced by some medicinalplants used in the state of Sao Paulordquo Journal of Ethnopharma-cology vol 15 no 3 pp 261ndash269 1986

[9] E AGordon L J Guppy andMNelson ldquoThe antihypertensiveeffects of the Jamaican Cho-Cho (Sechium edule)rdquo The WestIndian Medical Journal vol 49 no 1 pp 27ndash31 2000

[10] T Siciliano N de Tommasi I Morelli and A Braca ldquoStudyof flavonoids of Sechium edule (Jacq) Swartz (Cucurbitaceae)different edible organs by liquid chromatography photodiodearray mass spectrometryrdquo Journal of Agricultural and FoodChemistry vol 52 no 21 pp 6510ndash6515 2004

[11] E Jimenez-Ferrer FHernandez BadilloMGonzalez-CortazarJ Tortoriello and M Herrera-Ruiz ldquoAntihypertensive activ-ity of Salvia elegans Vahl (Lamiaceae) ACE inhibition andangiotensin II antagonismrdquo Journal of Ethnopharmacology vol130 no 2 pp 340ndash346 2010

[12] H G Vogel Drug Discovery and Evaluation PharmacologicalAssays Springer 2nd edition 2002

[13] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition p 760 2006

[14] J-B Shen B Jiang and A J Pappano ldquoComparison of L-typecalcium channel blockade by nifedipine andor cadmium inguinea pig ventricular myocytesrdquo The Journal of Pharmacologyand Experimental Therapeutics vol 294 no 2 pp 562ndash5702000

[15] T Godfraind ldquoActions of nifedipine on calcium fluxes andcontraction in isolated rat arteriesrdquoThe Journal of Pharmacologyand Experimental Therapeutics vol 224 no 2 pp 443ndash4501983

[16] C J Weir ldquoIon channels receptors agonists and antagonistsrdquoAnaesthesia amp Intensive Care Medicine vol 11 no 9 pp 377ndash383 2010

[17] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition pp 914ndash915 2006

[18] A B Parekh and J W Putney Jr ldquoStore-operated calciumchannelsrdquo Physiological Reviews vol 85 no 2 pp 757ndash8102005

[19] T Schewe Y Steffen and H Sies ldquoHow do dietary flavanolsimprove vascular function A position paperrdquo Archives ofBiochemistry and Biophysics vol 476 no 2 pp 102ndash106 2008

[20] D K Maurya and T P A Devasagayam ldquoAntioxidant andprooxidant nature of hydroxycinnamic acid derivatives ferulicand caffeic acidsrdquo Food and Chemical Toxicology vol 48 no 12pp 3369ndash3373 2010

[21] Y Lee D-H Shin J-H Kim et al ldquoCaffeic acid phenethylester-mediated Nrf2 activation and I120581B kinase inhibition areinvolved in NF120581B inhibitory effect structural analysis for NF120581Binhibitionrdquo European Journal of Pharmacology vol 643 no 1pp 21ndash28 2010

[22] J Chen X Chen Y Lei et al ldquoVascular protective potential ofthe total flavanol glycosides from Abacopteris penangiana viamodulating nuclear transcription factor-120581B signaling pathwayand oxidative stressrdquo Journal of Ethnopharmacology vol 136 no1 pp 217ndash223 2011

[23] J Summanen P Vuorela J-P Rauha et al ldquoEffects of simplearomatic compounds and flavonoids on Ca2+ fluxes in ratpituitary GH

4

C1

cellsrdquo European Journal of Pharmacology vol414 no 2-3 pp 125ndash133 2001

[24] Y Zhang Y Cao Q Wang L Zheng J Zhang and L He ldquoApotential calcium antagonist and its antihypertensive effectsrdquoFitoterapia vol 82 no 7 pp 988ndash996 2011

Evidence-Based Complementary and Alternative Medicine 7

0 2 4 6 8 10 12 14 16 18

Time (min)

02040608

times104

Inte

nsity

12

3

4 5

(a)

100 200 300 400

mz

0

500

1000

1500

1603 1972

Ext00372d minusMS 107ndash109min 100 = 1359

3763

Inte

nsity

(b)

Figure 6 Mass chromatogram of fraction R14 (a) and its massabsorption spectrum (b)

this work has the purpose of simulating an alteration in theTPR increasing blood pressure by the administration of AGII and triggering a general vasoconstriction reaction Drugdiscovery [12] describes this assay as an AG II antagonismmodel

The vagotomization of the rats eliminates the cardio-vascular reflexes without interfering with the heart rateand normal blood pressure allowing AG II to induce anincrease of blood pressure inciting an acute vasoconstrictionwhen administered intravenously without any interventionof the sympathetic and parasympathetic response whichare responsible for the immediate homeostatic control ofblood pressure The ganglionic-blockade purpose is to blockthe transmission of nerve impulses through the autonomicganglia [13] impairing the vasculature to compensate bloodpressure when administered AG II or the extract evaluated

The results obtained from this model allowed us notonly to confirm the antihypertensive effect of this plantbut also to identify the probable action mechanism Theextracts of S edule may have an AG II antagonism activityThis action mechanism can be modulated through directantagonism of the AG II receptor AT

1or by the intervention

on calciumfluxes activated byAG II impeding the immediatevasoconstriction response to the iv administration of AG II

In the isolated aorta assay AG II vasoconstriction actionwas dependent on Ca++ concentration where it was observedthat the increment in Ca++ promoted a rise of the contractionof the aorta when a single concentration of AG II wasadministered Nifedipine was used as a pharmacologicalcontrol it specifically blocks L-type calcium channels as acompetitive antagonist [14] on the calcium influx that canbe through depolarization or by receptor-response coupling[15] which in this assay was triggered by AG II The SeRHA

extract in comparison to Nifedipine responded as an irre-versible antagonist (also called pharmacologic antagonist)that shifts the dose-response curve downward indicating thatthe agonist can no longer exertmaximal effect at any dose Allthree concentrations of the extract that were tested not onlyinhibited the aorta contraction but also altered the EC

50as a

competitive antagonist would do [16]This behaviour confirms the AG II antagonist effect

although it could also have a calcium antagonist effectThe activity of SeRHA extract can be associated with anAG II receptor blocking action as well as obstructing thesecondmessenger system initiated by AG II which promotesthe efflux of sarcoplasmic calcium that activates the storeoperated channels (SOC) that allows more calcium to enterthe cell and form a calcium-calmodulin complex That endsin vascular contraction [17 18]

With these results the antihypertensive and vasorelaxantactivity of S edule root extract were demonstrated thereforea chemical separation was carried out obtaining a firstfraction SeRAce whichwas summited to chemical separationand the most chemically relevant fractions obtained wereanalysed on the acute hypertensive model two of them hadthe most pharmacological activity (R14 and R17) and werethen analysed by HPLC as well as SeRHA and SeRAce Thechemical results allowed us to identify most polyphenoliccompounds like flavonoids and phenylpropanoids Vitexinwas identified in SeRHA and SeRAce as well as coumaric andcinnamic acid in contrast with the extracts fractions R14 andR17 predominantly had coumaric and cinnamic acid Thisinformation is relevant and consistent to the results obtainedfrom the pharmacological experiments

Polyphenolic compounds have a very wide and importantbiological activity regarding cardiovascular diseases Mainlyin the regulation of high blood pressure recent studies areevoked on inflammation and ROS scavenging properties ofthis type of compounds [19ndash22]Thus there have been studieson flavonoids and cinnamic acid derivative on their calciumantagonism and vasorelaxant activity [23 24]

Liew et al [25] demonstrated that red wine polyphenolslike resveratrol act as calcium channel antagonists loweringfree intracellular Ca++ Summanen et al [23] presented thatnumerous simple phenolic compounds like cinnamic acidderivatives and flavonoids have a potent inhibition of Ca++entry by highK+-evoked activity the effects were comparableto those of verapamil They presented an inhibitory activityagainst Ca++ entry similar to the one of another classof natural Ca++ channel antagonists like furanocoumarinsidentified by Vuorela et al [26] Other studies of extracts ofGentiana floribunda that contained flavonoids and tanninsamong other compounds were effective for lowering bloodpressurewith a vasorelaxant effectmediated by the inhibitionof Ca++ influx via membranous calcium channels and itsrelease from the intracellular stores [27]

The presence of cinnamic acid derivatives in the Sedule extracts and fractions could be responsible for theangiotensin II and calcium antagonist effect which wereestablished with the pharmacological assays which aredesigned to identify a specific action mechanism Cinnamicacid derivatives are a group of natural compounds that have

8 Evidence-Based Complementary and Alternative Medicine

been studied in different antihypertensive models mostly asanti-inflammatory and antioxidant activity although thesestudies are based on chronic hypertension assays whichoriginate by the alterations of Ca++ fluxes in the vascularsmooth muscle and on the reninmdashangiotensinmdashaldosteronesystem

5 Conclusions

In conclusion the results obtained in this work demonstratethat S edule extracts have an antihypertensive activity whichis consistentwith the traditional use inMexicoThus the phy-tochemical analysis was not precise on a specific compoundand the richness in polyphenols opens a new range of inquiryfor other action mechanisms of S edule extracts related toinflammation and oxidative stress damage that is related tohypertension and endothelial dysfunction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was partially supported by CONACyT Mexico(SNI3229152834-M) IMSSMexico (FISIMSSPROT348)and CONACyT Mexico (Salud113632) Grants This paperis taken in part from the PhD of Galia Lombardo Earl(Programa de Doctorado en Ciencias Biologicas y de laSalud) belonging to the Universidad Autonoma Metropoli-tana (UAM) with a Doctoral fellowship from CONACyTMexico (Registry no 208601202091)

References

[1] H Pipitone Oaxaca Prehispanica CIDE (Centro de Inves-tigacion y Docencia Economica) Mexico DF Mexico 1stedition 2006

[2] SAGARPA ldquoBrevesmonografias agrıcolasrdquo 2005 httpw4siapsagarpagobmxAppEstadomonografiasHortalizasChayotehtml

[3] C Monroy-Ortiz and P Castillo-Espana Plantas MedicinalesUtilizadas en el Estado de Morelos UAEM-CONABIO Cuer-navaca Morelos Mexico 2nd edition 2007

[4] Biblioteca Digital de la Medicina Tradicional httpwwwmedicinatradicionalmexicanaunammxflora2phpl=4amppo=mamampte=Chayoteampid=6407ampclave region=34

[5] V A Argueta ldquoSechium edulerdquo in Atlas de las Plantas de laMedicina Tradicional Mexicana A L Cano and M E RodarteEds pp 393ndash394 Instituto Nacional Indigenista Biblioteca dela Medicina Tradicional Mexicana Mexico DF Mexico 1994

[6] R Lira J Castrejon S Zamudio and C Rojas-ZentenoldquoPropuesta de ubicacion taxonomica para los chayotes silvestres(Sechium edule Cucurbitaceae) de Mexicordquo Acta BotanicaMexicana vol 49 pp 47ndash61 1999

[7] X Lozoya ldquoMexican medicinal plants used for treatment ofcardiovascular diseasesrdquoAmerican Journal of Chinese Medicinevol 8 no 1-2 pp 86ndash95 1980

[8] A R de Ribeiro M Fiuza and F de Barros ldquoAcute antihy-pertensive effect in conscious rats produced by some medicinalplants used in the state of Sao Paulordquo Journal of Ethnopharma-cology vol 15 no 3 pp 261ndash269 1986

[9] E AGordon L J Guppy andMNelson ldquoThe antihypertensiveeffects of the Jamaican Cho-Cho (Sechium edule)rdquo The WestIndian Medical Journal vol 49 no 1 pp 27ndash31 2000

[10] T Siciliano N de Tommasi I Morelli and A Braca ldquoStudyof flavonoids of Sechium edule (Jacq) Swartz (Cucurbitaceae)different edible organs by liquid chromatography photodiodearray mass spectrometryrdquo Journal of Agricultural and FoodChemistry vol 52 no 21 pp 6510ndash6515 2004

[11] E Jimenez-Ferrer FHernandez BadilloMGonzalez-CortazarJ Tortoriello and M Herrera-Ruiz ldquoAntihypertensive activ-ity of Salvia elegans Vahl (Lamiaceae) ACE inhibition andangiotensin II antagonismrdquo Journal of Ethnopharmacology vol130 no 2 pp 340ndash346 2010

[12] H G Vogel Drug Discovery and Evaluation PharmacologicalAssays Springer 2nd edition 2002

[13] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition p 760 2006

[14] J-B Shen B Jiang and A J Pappano ldquoComparison of L-typecalcium channel blockade by nifedipine andor cadmium inguinea pig ventricular myocytesrdquo The Journal of Pharmacologyand Experimental Therapeutics vol 294 no 2 pp 562ndash5702000

[15] T Godfraind ldquoActions of nifedipine on calcium fluxes andcontraction in isolated rat arteriesrdquoThe Journal of Pharmacologyand Experimental Therapeutics vol 224 no 2 pp 443ndash4501983

[16] C J Weir ldquoIon channels receptors agonists and antagonistsrdquoAnaesthesia amp Intensive Care Medicine vol 11 no 9 pp 377ndash383 2010

[17] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition pp 914ndash915 2006

[18] A B Parekh and J W Putney Jr ldquoStore-operated calciumchannelsrdquo Physiological Reviews vol 85 no 2 pp 757ndash8102005

[19] T Schewe Y Steffen and H Sies ldquoHow do dietary flavanolsimprove vascular function A position paperrdquo Archives ofBiochemistry and Biophysics vol 476 no 2 pp 102ndash106 2008

[20] D K Maurya and T P A Devasagayam ldquoAntioxidant andprooxidant nature of hydroxycinnamic acid derivatives ferulicand caffeic acidsrdquo Food and Chemical Toxicology vol 48 no 12pp 3369ndash3373 2010

[21] Y Lee D-H Shin J-H Kim et al ldquoCaffeic acid phenethylester-mediated Nrf2 activation and I120581B kinase inhibition areinvolved in NF120581B inhibitory effect structural analysis for NF120581Binhibitionrdquo European Journal of Pharmacology vol 643 no 1pp 21ndash28 2010

[22] J Chen X Chen Y Lei et al ldquoVascular protective potential ofthe total flavanol glycosides from Abacopteris penangiana viamodulating nuclear transcription factor-120581B signaling pathwayand oxidative stressrdquo Journal of Ethnopharmacology vol 136 no1 pp 217ndash223 2011

[23] J Summanen P Vuorela J-P Rauha et al ldquoEffects of simplearomatic compounds and flavonoids on Ca2+ fluxes in ratpituitary GH

4

C1

cellsrdquo European Journal of Pharmacology vol414 no 2-3 pp 125ndash133 2001

[24] Y Zhang Y Cao Q Wang L Zheng J Zhang and L He ldquoApotential calcium antagonist and its antihypertensive effectsrdquoFitoterapia vol 82 no 7 pp 988ndash996 2011

8 Evidence-Based Complementary and Alternative Medicine

been studied in different antihypertensive models mostly asanti-inflammatory and antioxidant activity although thesestudies are based on chronic hypertension assays whichoriginate by the alterations of Ca++ fluxes in the vascularsmooth muscle and on the reninmdashangiotensinmdashaldosteronesystem

5 Conclusions

In conclusion the results obtained in this work demonstratethat S edule extracts have an antihypertensive activity whichis consistentwith the traditional use inMexicoThus the phy-tochemical analysis was not precise on a specific compoundand the richness in polyphenols opens a new range of inquiryfor other action mechanisms of S edule extracts related toinflammation and oxidative stress damage that is related tohypertension and endothelial dysfunction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was partially supported by CONACyT Mexico(SNI3229152834-M) IMSSMexico (FISIMSSPROT348)and CONACyT Mexico (Salud113632) Grants This paperis taken in part from the PhD of Galia Lombardo Earl(Programa de Doctorado en Ciencias Biologicas y de laSalud) belonging to the Universidad Autonoma Metropoli-tana (UAM) with a Doctoral fellowship from CONACyTMexico (Registry no 208601202091)

References

[1] H Pipitone Oaxaca Prehispanica CIDE (Centro de Inves-tigacion y Docencia Economica) Mexico DF Mexico 1stedition 2006

[2] SAGARPA ldquoBrevesmonografias agrıcolasrdquo 2005 httpw4siapsagarpagobmxAppEstadomonografiasHortalizasChayotehtml

[3] C Monroy-Ortiz and P Castillo-Espana Plantas MedicinalesUtilizadas en el Estado de Morelos UAEM-CONABIO Cuer-navaca Morelos Mexico 2nd edition 2007

[4] Biblioteca Digital de la Medicina Tradicional httpwwwmedicinatradicionalmexicanaunammxflora2phpl=4amppo=mamampte=Chayoteampid=6407ampclave region=34

[5] V A Argueta ldquoSechium edulerdquo in Atlas de las Plantas de laMedicina Tradicional Mexicana A L Cano and M E RodarteEds pp 393ndash394 Instituto Nacional Indigenista Biblioteca dela Medicina Tradicional Mexicana Mexico DF Mexico 1994

[6] R Lira J Castrejon S Zamudio and C Rojas-ZentenoldquoPropuesta de ubicacion taxonomica para los chayotes silvestres(Sechium edule Cucurbitaceae) de Mexicordquo Acta BotanicaMexicana vol 49 pp 47ndash61 1999

[7] X Lozoya ldquoMexican medicinal plants used for treatment ofcardiovascular diseasesrdquoAmerican Journal of Chinese Medicinevol 8 no 1-2 pp 86ndash95 1980

[8] A R de Ribeiro M Fiuza and F de Barros ldquoAcute antihy-pertensive effect in conscious rats produced by some medicinalplants used in the state of Sao Paulordquo Journal of Ethnopharma-cology vol 15 no 3 pp 261ndash269 1986

[9] E AGordon L J Guppy andMNelson ldquoThe antihypertensiveeffects of the Jamaican Cho-Cho (Sechium edule)rdquo The WestIndian Medical Journal vol 49 no 1 pp 27ndash31 2000

[10] T Siciliano N de Tommasi I Morelli and A Braca ldquoStudyof flavonoids of Sechium edule (Jacq) Swartz (Cucurbitaceae)different edible organs by liquid chromatography photodiodearray mass spectrometryrdquo Journal of Agricultural and FoodChemistry vol 52 no 21 pp 6510ndash6515 2004

[11] E Jimenez-Ferrer FHernandez BadilloMGonzalez-CortazarJ Tortoriello and M Herrera-Ruiz ldquoAntihypertensive activ-ity of Salvia elegans Vahl (Lamiaceae) ACE inhibition andangiotensin II antagonismrdquo Journal of Ethnopharmacology vol130 no 2 pp 340ndash346 2010

[12] H G Vogel Drug Discovery and Evaluation PharmacologicalAssays Springer 2nd edition 2002

[13] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition p 760 2006

[14] J-B Shen B Jiang and A J Pappano ldquoComparison of L-typecalcium channel blockade by nifedipine andor cadmium inguinea pig ventricular myocytesrdquo The Journal of Pharmacologyand Experimental Therapeutics vol 294 no 2 pp 562ndash5702000

[15] T Godfraind ldquoActions of nifedipine on calcium fluxes andcontraction in isolated rat arteriesrdquoThe Journal of Pharmacologyand Experimental Therapeutics vol 224 no 2 pp 443ndash4501983

[16] C J Weir ldquoIon channels receptors agonists and antagonistsrdquoAnaesthesia amp Intensive Care Medicine vol 11 no 9 pp 377ndash383 2010

[17] A C Guyton and J E Hall Textbook of Medical PhysiologyElsevier Saunders 11th edition pp 914ndash915 2006

[18] A B Parekh and J W Putney Jr ldquoStore-operated calciumchannelsrdquo Physiological Reviews vol 85 no 2 pp 757ndash8102005

[19] T Schewe Y Steffen and H Sies ldquoHow do dietary flavanolsimprove vascular function A position paperrdquo Archives ofBiochemistry and Biophysics vol 476 no 2 pp 102ndash106 2008

[20] D K Maurya and T P A Devasagayam ldquoAntioxidant andprooxidant nature of hydroxycinnamic acid derivatives ferulicand caffeic acidsrdquo Food and Chemical Toxicology vol 48 no 12pp 3369ndash3373 2010

[21] Y Lee D-H Shin J-H Kim et al ldquoCaffeic acid phenethylester-mediated Nrf2 activation and I120581B kinase inhibition areinvolved in NF120581B inhibitory effect structural analysis for NF120581Binhibitionrdquo European Journal of Pharmacology vol 643 no 1pp 21ndash28 2010

[22] J Chen X Chen Y Lei et al ldquoVascular protective potential ofthe total flavanol glycosides from Abacopteris penangiana viamodulating nuclear transcription factor-120581B signaling pathwayand oxidative stressrdquo Journal of Ethnopharmacology vol 136 no1 pp 217ndash223 2011

[23] J Summanen P Vuorela J-P Rauha et al ldquoEffects of simplearomatic compounds and flavonoids on Ca2+ fluxes in ratpituitary GH

4

C1

cellsrdquo European Journal of Pharmacology vol414 no 2-3 pp 125ndash133 2001

[24] Y Zhang Y Cao Q Wang L Zheng J Zhang and L He ldquoApotential calcium antagonist and its antihypertensive effectsrdquoFitoterapia vol 82 no 7 pp 988ndash996 2011

Evidence-Based Complementary and Alternative Medicine 9

[25] R Liew M A Stagg K T MacLeod and P Collins ldquoThered wine polyphenol resveratrol exerts acute direct actions onguinea-pig ventricular myocytesrdquo European Journal of Pharma-cology vol 519 no 1-2 pp 1ndash8 2005

[26] H Vuorela P Vuorela K Tornquist and S Alaranta ldquoCalciumchannel blocking activity screening methods for plant derivedcompoundsrdquo Phytomedicine vol 4 no 2 pp 167ndash181 1997

[27] A Khan M R Mustafa A U Khan and D D Muru-gan ldquoHypotensive effect of Gentiana floribunda is mediatedthroughCa++ antagonism pathwayrdquoComplementaryampAlterna-tive Medicine vol 12 article 121 2012