Journal of Ethnopharmacology 90 (2004) 191–194

Influence of aqueous extract fromNeurada procumbens L.on blood pressure of rats

H.B. Chen∗, M.W. Islam, R. Radhakrishnan, S.A. Wahab, M.A. NajiDepartment of Pharmacology and Toxicology, Zayed Complex for Herbal Research and Traditional Medicine,

Ministry of Health, Post Box 29300, Abu Dhabi, Saudi Arabia

Received 20 May 2002; received in revised form 11 September 2003; accepted 12 September 2003

Abstract

Neurada procumbens is a desert plant in the Arabian Peninsula. It has been considered edible by Bedouin and has been used traditionallyas a medicinal herb. During a screening test of Arabian plants, the aqueous extract ofNeurada procumbens increased the blood pressure ofanaesthetized normotensive rats when it was administered orally. Further studies proved it elevated the blood pressure of conscious SHR, andproduced vasoconstriction on the aortic strips of rats in vitro, which was reduced partially by phentolamine. This study demonstrates that theaqueous extract of the plant has an effect of increasing blood pressure that might be mediated through alpha-adrenergic receptors. Thoughmore investigations are needed to prove its effect in humans, the present study warns thatNeurada procumbens might not be so safe as it hasbeen considered, and people, especially those with cardiovascular diseases, should be careful when they use the plant.© 2003 Published by Elsevier Ireland Ltd.

Keywords: Neurada procumbens; Blood pressure; Vasoconstriction

1. Introduction

Neurada procumbens L. (Rosaceae), called sa‘ada by Ara-bian people, is a desert plant widespread on shallow and deepsands in the Arabian Peninsula. It is a grey-green, annualherb with numerous prostrate branches radiating to 20 cmfrom the roots. The leaves are relatively thick with clearmidrib, wavy margins, and bluntly rounded tip on its stalk.Its flowers, blooming from January to May, are about 1 cmdiameter, solitary in leaf axils with small petals. The fruit isa distinctive disc 1–1.5 cm across, rough and spiny above,smooth beneath and this usually remains as collar aroundbase stem of new plants (Western, 1989; Hepper and Friis,1994).

Neurada procumbens is one kind of food of camels, but ithas been considered safe and edible and Bedouin eat it some-times (James, 1990). In traditional Arabian medicine, theplant has been used to treat diarrhea and dysentery; as well,it has been used as a tonic to ‘increase heart and respirationfunctions’. During a screening test of Arabian plants, theaqueous extract ofNeurada procumbens caused increasedblood pressure in anaesthetized normotensive rats. This led

∗ Corresponding author. Fax:+971-2-6313-742.

to the present study, to investigate and prove its effects onthe blood pressure and vascular smooth muscles of rats.

2. Methodology

2.1. Plant and its extract

Neurada procumbens L. was collected from Umm AlQuwein of the United Arab Emirates in April, 2001 andwas authenticated by the botanists in the Zayed Complex forHerbal Research and Traditional Medicine, where a voucherspecimen (w139) has been deposited. The whole plant wasdried under shade and powdered. The powder was exhaus-tively extracted with distilled water. The solvent of the liquidextract was removed completely by evaporation under vac-uum at 40◦C, using a Buchi Rotary Evaporator. The driedextract contained 31/100 g of the starting crude material.

2.2. Animals

Wistar rats of either sex weighing 300–350 g were usedfor the study. Their diastolic and systolic blood pressureunder anesthesia was 63±4 mmHg and 110±5 mmHg. Malespontaneous hypertensive rats (SHR) weighing 350–400 gwere used for experiment and their blood pressure was 116±

0378-8741/$ – see front matter © 2003 Published by Elsevier Ireland Ltd.doi:10.1016/j.jep.2003.09.045

192 H.B. Chen et al. / Journal of Ethnopharmacology 90 (2004) 191–194

9 mmHg and 150± 5 mmHg. The animals were bred in theAnimal Holding Unit of the complex under the standardenvironment condition.

2.3. Blood pressure in anaesthetized normotensive rats

The rats were anaesthetized with urethane (1.2 g/kg, i.p.)and the carotid artery was cannulated (Shuyun et al., 1991).The blood pressure was measured directly from the can-nula using a transducer–amplifier–recorder assembly (LEC-TROMED, UK) and the chart recorder was calibrated inmmHg to measure the blood pressure. For administration ofthe extract, a 1 cm abdominal incision was made to exposethe stomach. After a stabilization period of 30 min, the ini-tial value of the blood pressure was recorded. The extract ofNeurada procumbens (1 g/kg) or normal saline was injectedinto the stomach through the abdominal incision and the in-cision was then closed. The blood pressure was recordedat 30, 60, 90, 120, 150, and 180 min after the administra-tion. The heart rate was later manually computed from therecording.

2.4. Blood pressure in conscious SHR

A system of Dataquest ARTTM 2.1 PhysioTelemetrywas used for the experiment (Data Sciences International,2000). A Data Exchange Matrix connected the PhysioTelReceivers (Model RPC-1) and Ambient Pressure reference(Model APR-1) to the PCI card. A pressure transmitter(TA11PA-C40) was implanted into the abdominal cavityof SHR with its catheter connected to the dorsal aorta(Waynforth and Flecknell, 1994). The rats were used forthe experiment three weeks after the implantation.

At the first day of the experiment, the SHR were admin-istered orally with distilled water at 1 ml/100 g body weight.At the second day, the same SHR were administered orallywith the extract ofNeurada procumbens at 1 g/kg. Bloodpressures and heart rates were detected automatically byPhysioTelemetry system for 6 h, from 1 h before and 5 h afterthe administration. The samples of blood pressure and heart

Table 1Influence of the aqueous extract ofNeurada procumbens (NP) on the blood pressure and heart rate of the anaesthetized normotensive rats (n = 6),expressed as percentage of the initial value

0 min 30 min 60 min 90 min 120 min 150 min 180 min

DBPControl 100 94± 5 92 ± 8 94 ± 7 91 ± 8 87 ± 7 81 ± 5NP 100 101± 5 105± 7 110± 8 114± 11 116± 10∗ 109 ± 10∗

SBPControl 100 97± 4 95 ± 3 97 ± 3 97 ± 3 95 ± 3 88 ± 3NP 100 104± 2 105± 4 109± 5 109± 7 109± 5∗ 104 ± 6∗

HRControl 100 104± 5 103± 4 106± 6 111± 6 111± 6 110± 7NP 100 109± 6 108± 6 110± 6 113± 8 113± 8 115± 7

DBP: diastolic blood pressure; SBP: systolic blood pressure; HR: heart rate.∗ Significantly different from control value atP < 0.05.

rate were collected continuously for 10 s in every 5 min. Themean values of the blood pressure and heart rate in 1 h wereused to present the blood pressure and heart rate in this pe-riod.

2.5. Rat aortic strips

The direct effect of the aqueous extract fromNueradaprocumbens on the vascular smooth muscles was evaluatedusing isolated rat aortic strips (Shuyun et al., 1991). Aor-tas were isolated from Wistar rats, spirally cut into stripsof 2 cm length and 3 mm width and suspended in an or-gan bath containing Kreb’s solution, bubbled with Carbogenand maintained at 37◦C. One gram resting tension was ap-plied to the tissue which was then allowed to equilibrate for30 min. The extract was added at concentrations of 0, 0.2,0.5, 1.0, and 2.0 mg/ml and the responses were recorded for10 min. Phentolamine at 150�M was added 10 min beforethe extract to check its influence.

2.6. Statistical analysis

All data are expressed as mean±S.E.M. The significanceof the difference between the means of data was evaluated bythe Student’st-test.P-values less than 0.05 were consideredsignificant.

3. Result

3.1. Blood pressure in anaesthetized normotensive rats

The aqueous extract ofNeurada procumbens, at 1 g/kgorally, significantly increased both diastolic and systolicblood pressure of the anaesthetized normotensive rats with-out significantly affecting their heart rate. The effect startedfrom 60 min after the administration and was maintaineduntil the end of the experiment, 180 min after the adminis-tration. The increases at 150 and 180 min was significant(Table 1).

H.B. Chen et al. / Journal of Ethnopharmacology 90 (2004) 191–194 193

Table 2Influence of the aqueous extract ofNeurada procumbens (NP) on the blood pressure and heart rate of conscious SHR (n = 7), expressed as percentageof the initial value

Zero hour First hour Second hour Third hour Fourth hour Fifth hour

DBPWater 100 108± 3 94 ± 4 96 ± 3 97 ± 3 94 ± 3NP 100 112± 5 111± 5∗ 103 ± 6 101± 4 96 ± 4

SBPWater 100 106± 3 93 ± 3 95 ± 2 96 ± 3 94 ± 3NP 100 111± 4 111± 5∗ 103 ± 5 100± 3 99 ± 4

HRWater 100 109± 2 95 ± 3 93 ± 3 96 ± 3 93 ± 3NP 100 104± 3 103± 4 99 ± 6 97 ± 5 96 ± 4

DBP: diastolic blood pressure; SBP: systolic blood pressure; HR: heart rate.∗ Significantly different from the value of water treatment atP < 0.05.

3.2. Blood pressure in conscious SHR

The aqueous extract ofNeurada procumbens, at 1 g/kgorally, increased both diastolic and systolic blood pressure,from the first hour till the third hour after the administra-tion. The increasing during the second hour was significant(P < 0.05). The heart rate of the second hour also increasedthough not significantly (Table 2).

3.3. Rat aortic strips

The aqueous extract ofNeurada procumbens, at theconcentrations of 0.2, 0.5, 1.0, and 2.0 mg/kg, produced adose-dependent increase in the resting tension of the iso-lated rat aortic strips (Fig. 1). The vasoconstrictive effectwas reduced partially by phentolamine (150�M).

0

0.05

0.1

0.15

0.2

0.25

0.3

0 2 4 6 8 10 12

Minutes

g

control

NP0.2mg/ml

NP0.5mg/ml

NP1.0mg/ml

NP2.0mg/ml

Fig. 1. Influence of the aqueous extract ofNeurada procumbense on resting tension of rat aortic strips (n = 6); NP: Neurada procumbense.

4. Discussion

The present study revealed that the aqueous extract ofNeurada procumbens, oral administration, significantly in-creased the diastolic and systolic blood pressure in anaes-thetized normotensive rats and conscious SHR. In vitro, theextract produced a significant vasoconstrictive effect on aor-tic strips, which was reduced by pre-treatment with phento-lamine. This suggests that the vasoconstrictive effect causedby Neurada procumbens is, at least in part, mediated throughalpha-adrenergic receptors.

There is only one research paper aboutNeurada procum-bens, which reported that the plant contained alkaloids,flavoniods, saponins, sterols/triterpenes, coumarins, volatileoils, and tannins (Mossa et al., 1983). The same pa-per also reported that the ethanolic extract ofNeurada

194 H.B. Chen et al. / Journal of Ethnopharmacology 90 (2004) 191–194

procumbens reduced the blood pressure in rabbits whenit was administered intravenously. The different results ofNeurada procumbens on blood pressure from the presentstudy and the previous paper are considered here to bedue to the different extractive solvents and/or differentadministrations.

Bedouin and Arabs usually eatNeurada procumbens di-rectly or take its decoction as a medicine. Therefore theuse of an aqueous extract of the plant and its oral ad-ministration used in the present study are similar to folkusage.

Accordingly, Neurada procumbens might not be sosafe as it has been considered. Its effects on blood pres-sure and vascular smooth muscles exhibited in this studyimply that the plant might have similar effects in hu-man beings though more investigations are needed. Thisstudy also warns people, especially those suffering fromcardiovascular diseases, to be careful when they use theplant.

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Hepper, F.N., Friis, I., 1994. The Plants of Pehr Forsskal’s FloraAegyptiaco-Arabica. Royal Botanic Gardens, Kew in Association withthe Botanical Museum, Copenhagen, p. 206.

James. P.M., 1990. Flora of Eastern Saudi Arabia. Kegan Paul InternationalLimited, England, pp. 29–30.

Mossa, J.S., Al-Yahya, M.A., Al-Meshal, I.A., Tariq, M., 1983. Phyto-chemical and biological screening of Saudi medicinal plants—part 5.Fitoterapia LIV, 147–152.

Mossa, J.S., Al-Yahya, M.A., Al-Meshal, I.A., Tariq, M., 1983. Phyto-chemical and biological screening of Saudi medicinal plants—part 4.Fitoterapia LIV, 75–80.

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