Garlic

Known for their pungent odor, garlic bulbs have been revered as both a food and medicine in many cultures for millennia. Construction workers who built the Egyptian pyramids were supposedly given huge rations of garlic to sustain their resistance against fevers. Legend has it that gravediggers in early eighteenth-century France drank a concoction of macerated garlic in wine to protect themselves against a plague. And during the two world wars, military physicians gave garlic to their patients as a preventive against gangrene.

The primary active compound in garlic is alliin, an odorless substance derived from the sulfur-containing amino acid, cysteine. However, alliin is found only within the intact cells of garlic. When garlic bulbs are crushed, the cell walls are broken, and an enzyme, allinase, converts alliin into a degradation product called allicin (diallyldisulfide-S-oxide). Allicin is an unstable compound that gives garlic its characteristic odor. Allicin is more active than alliin, and it readily forms other odorous sulfur-containing active constituents.

Medicinal Uses

Historical uses: all infections both internally and as a poultice. Used as a warming herb and as preventive for colds and flu, menstrual pain, mouthwash, and as a douche. Anthelmintic (expels worms).

Traditional actions: antihypertensive, anticholesterolemic, antilipidemic, reduces platelet aggregration, vasodilator, expectorant, antihistaminic, antimicrobial

Clinical applications: treatment and prevention of atherosclerosis, elevated blood lipids, and thrombosis. Also used to stabilize blood sugar level, and for gastrointestinal infections by positively affecting intestinal flora.

Numerous in vitro and in vivo investigations show that garlic has broad spectrum antimicrobial activity against bacteria, viruses, fungi, and intestinal parasites (helminths). Garlic also has immune-enhancing, antioxidant, and vasodilating activity. In both in vitro and in vivo studies, garlic produces anti-inflammatory, blood-sugar lowering (antidiabetic), and anticancer effects.

Research on garlic shows unequivocally that it can help prevent atherosclerosis through its effects on elevated lipids and blood pressure. Studies on both animals and humans indicate that garlic favorably shifted the high-density lipoprotein:low-density lipoprotein ratio toward lowered LDL and higher HDL values. It also lowered plasma viscosity and improved both blood fluidity and capillary blood flow. Garlic increased fibrinolytic activity, prolonged bleeding and clotting time, and inhibited platelet aggregations. Garlic consumption reduced blood pressure in hypertensive patients.

Allicin probably accounts for antibiotic and antiplatelet activity. Allicin also lowers cholesterol levels by blocking lipid synthesis and by increasing the excretion of neutral and acidic sterols. Ajoene prevents blood clots by inhibiting platelet aggregation in vitro and in vivo in a dose-dependent and reversible manner. By inhibiting platelet aggregation, ajeone has a protective effect against atherosclerosis, coronary thrombosis, and stroke.

Another Name

Garlic (English)

Allium sativum (Botanical)

Alliaceae (Plant Family)

Allii sativi bulbus (Pharmacopeial)