1) SUGGESTED THERAPEUTIC EFFECTS -
a) ALLIUM SATIVUM (GARLIC) - Anticoagulant, antihypertensive, antimicrobial, immune system modulator, antilipidemic agent, hypoglycemic agent, and fibrinolytic activity (Abdullah et al, 1988; Anon, 1976).
b) ALLIUM CEPA (ONION) - Hypocholesterolemic, fibrinolytic agents (most likely propienyl and methyl sulfides), inhibition of thrombocyte aggregation, fatty acid oxygenases, antiasthmatics (Bayer et al, 1989; Anon, 1976).
c) ALLIUM URSINUM (WILD GARLIC) - Inhibits 5-lipooxygenase, cyclooxygenase, thrombocyte aggregation, and angiotensin I converting enzyme (Sendl et al, 1992).
2) CHOLESTEROL AND TRIGLYCERIDES -
a) RATS - Administration of 100 mg/kg/day of garlic oil to rats blocked increases in cholesterol, triglycerides and total lipids when compared to controls who were also fed a high sucrose diet (Adamu et al, 1982). Another rat study confirmed these results (Kamanna & Chandrasekhara, 1984). The anti-atherogenic action is present in the oily fraction of garlic (Jain & Konar, 1978).
b) When tested in humans given 100 g of butter in a fatty diet, a 7% increase from prestudy cholesterol levels was reported in the non-treated groups, and a 7% decrease was reported in the group also given 50 grams of garlic. Serum cholesterol levels were measured 3 hours post ingestion. There were only 10 subjects in the study (Bordia & Bansal, 1973).
c) Another study involved 20 healthy volunteers. Serum cholesterol and triglycerides were decreased, while high density lipoproteins were increased after a dose of 0.25 mg/kg/day of garlic oil (Bordia, 1981).
d) Similar results were seen in 62 patients with coronary artery disease and elevated cholesterol who used garlic for 10 months (Bordia, 1981); and in a study done by Sharma et al (1978).
e) There have been eleven studies with doses of 600 to 900 mg of garlic powder per day that have shown an average reduction of serum cholesterol and triglycerides of 10% to 13% (Grunwald, 1990; Mader, 1990).
f) Onion reduced hypercholesterolemia from 7% to 33% in 9 of 18 patients with blood cholesterol of 245 to greater than 300 milligrams/deciliter. Patients ingested 15 mL of onion extract 2 or 3 times daily for at least 3 months. Of these patients, 33% had approximately a 5% decrease, 11.1% had a 5% to 9% decrease, 5.6% had a 10% to 14% decrease, and 16.7% had either a 15% to 19% decrease, a 20% to 40% decrease, or an increase in serum cholesterol levels (Louria et al, 1985).
3) FIBRINOLYTIC ACTIVITY -
a) Human volunteers fed 50 g of garlic with 100 g of butter had a 15% increase in fibrinolytic activity 3 hours post-ingestion, compared to a group fed the butter alone (Bordia & Bansal, 1973).
b) Bordia et al (1977) found a 95% increase in fibrinolytic activity in post MI patients over the initial post infarct period.
c) Amounts close to 3 to 4 grams/day may produce an effect on fibrinolytic activity (Roser, 1990).
4) PLATELET FUNCTION INHIBITION -
a) GARLIC -
1) Makheja et al (1979) found that garlic oil inhibited platelet function, most likely by thromboxane synthesis. Amounts close to 25 to 50 grams/day may alter platelet adhesiveness (Roser, 1990).
2) One very potent antithrombotic compound found in garlic is 4,5,9 trithiadodeca-1,6;11-triene 9 oxide (ajoene). Ajoene appears to inhibit platelet aggregation no matter what method of induction is used (Anon, 1994).
3) Ariga et al (1981) found that methylallyltrisulfide (found at 4 to 10% in the oil) inhibited ADP-induced platelet aggregation at under 10 micromoles/liter in plasma.
4) Fresh garlic also appears to inhibit platelet aggregation. One study found complete inhibition of platelet aggregation to 5-hydroxytryptamine for 1 hour after ingestion of 100 to 150 mg/kg of fresh garlic (Boullin, 1981). Not all studies are positive. Dried garlic, given in sugar coated tablets, had no effect on blood lipids or blood coagulation when administered in a double-blind study to 85 patients in doses of either 198 mg three times daily or 450 mg three times daily (Luley et al, 1986).
5) Apitz-Castro et al (1983) found that an alcoholic extract of garlic and 3 other specific factors from garlic inhibited platelet aggregation induced by a number of agents.
b) ONION -
1) No statistical difference was measured in platelet thromboxane production in one small study (n=5) of human volunteers ingesting 70 grams of raw onion (species not cited) daily for 7 days (Srivastava, 1989).
2) The n-butanol soluble fraction from Allium bakeri inhibits human platelet aggregation in vitro. The primary effective agent appeared to be adenosine (Okuyama et al, 1988).
3) Nine patients were fed either a high-fat or a low-fat meal. The high-fat meal induced an increase in platelet aggregation (p < 0.02) when compared with the low-fat meal. If 75 grams of onions (Allium cepa) were added to the high-fat meal, no significant increase in platelet aggregation was found. There was no significant change in fibrinolysis after the addition of the onion (Baghurst et al, 1977).
5) HYPOGLYCEMIC EFFECTS -
a) Rabbits given garlic had a 12% reduction in blood sugar (compared to 20% for tolbutamide) (Jain et al, 1973). Increases in serum insulin and improvement in liver glycogen storage has also been noted in humans taking garlic (Sitprija et al, 1987).
b) Onion has been shown to contain diphenylamine. When given to rabbits, pure diphenylamine caused a 21.7% to 33.4% reduction in blood sugar. A diethyl ether extract from onion produced a 34.8% to 50.3% reduction in blood glucose (Salveron & Cantoria, 1989).
6) ANTIBIOTIC -
a) ANTIBACTERIAL - Garlic does inhibit both gram-positive and gram-negative organisms. It is about 1% as effective as penicillin (Anon, 1994; Willis, 1956).
b) ANTIFUNGAL - Although tested as an antifungal with positive results, garlic has not proven to be very useful or popular as a general antifungal (Anon, 1994; Adetumbi & Lau, 1983; Amer et al, 1980; Moore & Atkins, 1977).
c) ANTIVIRAL - Garlic extract was shown to have antiviral activity against influenza B, human rhinovirus, vaccinia virus, vesicular stomatitis virus, parainfluenza type 3, and herpes simplex, but not against Coxsackie B1 virus (Weber et al, 1991; (Tsai et al, 1985). Various components of the garlic were tested. The order of virucidal activity, in decreasing order, was ajoene, allicin, allyl methylthiosulfinate, and methyl allylthiosulfinate (Weber et al, 1991).
d) AMEBICIDAL - Addition of 25 mcg/mL of crude garlic extract oil to cultures of Entamoeba histolytica trophozoites inhibited growth. Concentrations of about 50 mcg/mL produced irreversible killing (Mirelman et al, 1987).
7) ANTINEOPLASTIC -
a) When mice with malignancies were pretreated with garlic extract, no treated mice died in 6 months, whereas all control mice expired (Weisberger & Pensky, 1957). It is postulated that allicin may react with the sulfhydryl groups found in rapidly dividing cells, reducing their growth rate.
b) The germanium and selenium found in garlic may have some effect on reducing tumor growth rate. Garlic extracts have been shown to inhibit liver and buccal tumors in experimental animals (Anon, 1994; Hayes et al, 1987).
c) Garlic and onion were also shown to inhibit tumors promoted by phorbol-myristate acetate (Belman, 1983).
d) An epidemiologic study found that patients who ingested larger amounts of Allium vegetables had fewer stomach cancers than those who ate fewer. Not all other factors were controlled. Interviews were conducted, in China, with 564 patients with stomach cancer and 1,131 controls. Persons in the highest quartile of intake had only 40% of the risk of those in the lowest quartile (You et al, 1989).
8) ANTIHEPATOTOXIC EFFECT -
a) When tested in in-vitro and in-vivo animal models, garlic was shown to have a protective effect against hepatotoxicity induced by carbon tetrachloride and galactosamine (Hikino et al, 1986).
9) ANTIASTHMATIC EFFECT -
a) Alpha- and beta-unsaturated thiosulfinates found in Allium cepa exhibit antiasthmatic effects in vivo. Allergen-induced bronchial obstruction in guinea pigs was suppressed and in vitro inhibition of histamine release, leukotriene synthesis, and thromboxane production were noted in human cell cultures (Bayer et al, 1989; Dorsch et al, 1988).
10) ANTIHYPERTENSIVE EFFECT -
a) Administration of 15 mL of onion extract 2 to 3 times daily for 2 months decreased blood pressure in 13 of 20 patients with moderate hypertension (systolic pressure less than 185 mmHg and diastolic pressure less than 110 mmHg). The mean decrease was 6.6 mmHg (p = 0.000132) (Louria et al, 1985).