Garlic and OnionBy: Megan Malek

Historical Usage

Allium Genus

Garlic-Allium sativum L.◦ Hardneck (stiffneck)

6-11 cloves Circular clove formation

◦ Softneck Up to 24 cloves Several layers of cloves Artichoke Silverskin**

Onion-Allium cepa L.◦ Storage

Year around, pungent Yellow, white, red, purple

◦ Sweet Seasonal, sweeter

Bioactive CompoundsOnion

Volatile Isoalliin + LFS LF

Alliin + Alliinase allicin analogues (thiosulphinates)

Bis-sulphinesThiosulfonatesMono-sulphidesDi-sulphides• Non-volatile Cmpd:

Cepaenes

Non-volatileFlavonoids

◦Quercetin- skin & leaves

◦Anthocyanins(red onion) –outer scales

Saponins- bulb

Fructans-bulb & leaves

Bioactive CompoundsGarlic

Volatile◦Alliin + Alliinase

allicin (thiosulphinate)

◦Thiosulfonates◦Ajoene◦Vinyl-dithiins◦DADS◦DATS

• Non-volatile Cmpds: SAC & SAMC (AGE)

Alliin

Non-volatile◦Flavonoids

Myricetin-bulb

◦Saponins -bulb

◦Protease Inhibitors

◦Prostaglandin

Health Benefits of OnionAntioxidant Properties

o High quercetin concentrations

• 9 active compounds present in outer dry scales of onion

o High bioavailability o Lower risk of CHD

& myocardial infarction

(Ly et al, 2005)

MoA of Quercetin• Free radical scavenger

• Structural stability of 3 benzene rings

• H+ donating capacity of 4 hydroxyl groups

• Chelate metal ions• Preventing

hydroxyl radical production by inhibition of the Fenton rxn

• Prevent Ang II-induced ED• Inhibit overexpresssion of

p47 in NADPH oxidase

• Interactions with biomembranes• Penetrate the lipid bilayer of

membranes by anchoring to the polar heads of phospholipids

Health Benefits of OnionAntimicrobial Properties

Anti-fungal effects of onion extracts and garlic on growth of A. niger (Benkeblia, 2003)Antibacterial activity of

onion and garlic on S. aureus and Salmonella

Health Benefits of OnionAntimicrobial Properties

Fructans vs influenza-A virus

Effects of non-dialyzate (WH) and fructans on the influenza-A virus compared to control (Lee et al, 2012).

Fructans

High soluble fiber Stimulate growth of bifidobacteria and lactobacilli in the colon

Benefits:◦Low sweetness, calorie-free◦Low carcinogenicity◦Pre-biotic effect◦Increased mineral absorption◦Decreased serum cholesterol, TGs, and PLs◦Diarrhea prevention

Health Benefits of OnionCancerRaw Alliums vs esophageal and gastric cancer

(Gao et al, 1990)

Health Benefits of OnionCancer

(Knekt et al, 2002)

Health Benefits of OnionCardiovascular Disease

(Conquer et al, 1998)

Quercetin is highly bioavailable but no effect on cholesterol or lipids profile

Health Benefits of OnionCardiovascular Disease

(Bordia, 1996)

Onion and garlic showed lowering effect on TXB2

Health Benefits of OnionHypertension

(Sanchez et al, 2007)

Quercetin + isorhamnetin can prevent AngII-induced endothelial dysfunction by inhibiting p47 and superoxide production in vitro.

Health Benefits of OnionDiabetes

(Babu and Srinivasan, 1997)

Diabetic rats consuming a 3% onion diet had improved metabolic status-reduced hyperglycemia, reduced liver weight, lower cholesterol, LDLs, VLDL, PLs, and TGs.

Health Benefits of OnionDiabetes

(Islam et al, 2008)

Dietary onion with a high fat diet may impair the anti-diabetic effect of onion in rat models

Health Benefits of OnionInflammation

(Wang et al, 2013)

Welsh onion extract (WOE) decreased paw edema, NO, TNFα, lipid peroxide & increased catalase, SO dismutase, glutathione peroxidase in vivo

Health Benefits of OnionObesity

(Yoshinari et al, 2012)

The rats consuming the onion diet (3% & 5%) had lower body and adipose tissue weights compared to the control group with no onion diet after 18 days

Health Benefits of OnionAsthma

(Wagner et al, 1990)

Thiosulfinates are only effective at inhibiting cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) if at least one unsaturated or aromatic substituent was present

ProstaglandinInhibition

Onion oil and garlic oil inhibit COX and 12-lipoxygenase

Garlic extract acts as a prostaglandin

(Ali et al, 2000)

Health Benefits of GarlicAntioxidant Properties

(Rahman, 2000)

The subject’s platelet aggregation was significantly reduced after dietary supplementation of 5 mL of AGE per day for 13 weeks.

Health Benefits of GarlicAntimicrobial Properties

(Bakri and Douglas, 2004)

Garlic extract (51.1% w/v) which contains 220 mg/ml of allicin, was shown to inhibit P. gingivalis almost immediately and the inhibition of S. mutans was delayed but still effective.

Health Benefits of GarlicAntimicrobial Properties

(Coppi et al, 2005)

A four day regimen of allicin administered orally or intravenously significantly reduced parasitemias and increased the lifespan of the mice by 10 days

The mice injected with allicin showed inhibition against Plasmodium compared to the control group.

Health Benefits of GarlicCancer

(Ishikawa et al, 2006)

AGE administered to 55 cancer patients increased number and activity of NK cells.

Health Benefits of GarlicCardiovascular Disease

Garlic had no significance effect in all treatment groups when administered at 4 cloves of garlic/d on total cholesterol, LDLs, HDLs, and triglycerides.

(Gardner et al, 2007)

Health Benefits of GarlicCardiovascular Disease

Inhibition of platelet aggregation only occurred when garlic was administered at six capsules for one month in the CHD group

(Bordia et al, 1995)

Health Benefits of GarlicCardiovascular Disease

Total plasma cholesterol decreased in all rat groups, and significantly decreased in the raw garlic extract, which is rich in spirostanol saponins.

(Matsuura, 2001)

MoA of Saponins

• Perforation of cholesterol membrane• Interact with the cell

membrane of cholesterol and cause perforations

• Complex formation with cholesterol • Foam-like character of

saponins forms a complex with cholesterol in the intestinal lumen

Health Benefits of GarlicHypertension

The hypertensive group showed a significant decrease in to systolic and diastolic blood pressure, as well as, a significant decrease in oxidized LDLs and 8-iso-prostglandin F2α

(Dhawan & Jain, 2004)

Health Benefits of GarlicInflammation

Caffeic acid and SAC reduced oxidative stress and inflammation by regulating the activities of NF-κB and AP-1 and uracil indirectly exhibited an antioxidant effect by reducing COX-2 and inducible nitric oxide synthase expression levels

(Kim et al, 2013)

Safety & Rx Interactions-Garlic

Garlic is GRAS by FDA1-2 cloves or 4-6g garlic powder=safeSide effects:

◦Dermatitis ◦Aggravate throat and stomach◦Odoriferous garlic breath and perspiration◦Acid reflux

Rx Interactions◦Anticoagulant activity interfere w/ Warfarin◦Quercetin may increase Taxmoxifen bioavailability

(breast cancer Rx)

Safety/Toxicity- Garlic & Onion

◦Dermatological problems Dermatitis of the fingertips (garlic and onion)

◦Burns Garlic poultice

◦Asthmatic effect Garlic dust

◦Allergens DADS Allylpropyldisulfide allicin