Botanical Allium sativum

BOTANICAL NAME/FAMILY

• Allium sativum

OTHER NAMES

• Ail, ajo, allium, camphor of the poor, da-suan, knoblauch, la-juan, poor man’s treacle, rustic treacle, stinking rose

PLANT PARTS USED

·        Bulb, and oil from the bulb

CHEMICAL COMPONENTS

• Garlic bulbs contain organosulfur compounds (OSCs), protein (mainly alliinase), amino acids (such as arginine, lysine, threonine and tryptophan), fibre, lipids, phytic acid, saponins, beta-sitosterol and small quantities of vitamins and minerals such as vitamin C, vitamin E, beta-carotene, chromium, iron and selenium (Duke 2003). Of the numerous constituents present, it is the alliin component and resultant degradation products, such as allicin and ajoene, that produce much of the herb’s pharmacological activity.

MAIN ACTIONS                                

Garlic and many of its constituents have strong antioxidant activity and is capable of directly scavenging free radicals, and indirectly by enhancing endogenous antioxidant systems such as glutathione, superoxide dismutase, catalase and glutathione peroxidase

Other actions include

·        Anti-inflammatory, antioxidant, inhibits platelet aggregation and antithrombotic effects, protection against ischaemic and reperfusion injury, stimulates fibrinolysis, anti-atherosclerotic activity, antimicrobial.  Reduces blood sugar and cholesterol and blood pressure

DOSAGE RANGE

General guide

•        Fresh garlic: 2–5 g/day (ensure it is bruised, crushed or chewed).

•        Dried powder: 0.4–1.2 g/day.

•        AGEs have been studied in amounts ranging from 2.4 to 7.2 g/day.

•        Oil: 2–5 mg/day.

•        Garlic preparations that will provide 4–12 mg alliin daily.

•        Fluid extract (1:1): 0.5–2 mL three times daily.

According to clinical studies

•        Hypertension: 600–900 mg/day in divided doses (delivering approximately 5000–6000 microgram allicin potential).

•        Hyperlipidaemia: 600–9000 mg/day.

•        Fungal infection: topical 0.4–0.6% ajoene cream applied twice daily.

•        Occlusive arterial disease: 600–800 mg/day.

ADVERSE REACTIONS

Breath and body odour, allergic reactions, nausea, heartburn, flatulence, abdominal discomfort and diarrhoea have been reported

SIGNIFICANT INTERACTIONS

Saquinavir and ritonavir

A clinical study showed that garlic powder reduced blood levels of saquinavir and ritonavir due to stimulation of P450 isoenzymes, and therefore may reduce efficacy of drug — avoid using concurrently. However, in a clinical study of 10 participants, 10 mg of odourless garlic had no significant effect on the pharmacokinetics of ritonavir.

Anticoagulants

Theoretically, a pharmacodynamic interaction is possible when using garlic at high doses (> 7 g), in excess of usual dietary amounts; however, results from clinical studies cast doubt on this proposition. Published clinical studies have identified no significant action of enteric-coated or aged garlic on warfarin pharmacodynamics or pharmacokinetics. A double-blind, randomised, placebo-controlled pilot study of 48 patients demonstrated that the concomitant use of garlic containing 14.7 mg/day of S-allylcysteine and warfarin showed no adverse effects. An open-label, three-treatment, randomised, crossover clinical trial involving 12 healthy males, investigating potential effects of garlic and cranberry on warfarin (25 mg single dose), found that two garlic tablets daily containing 2000 mg of fresh garlic bulb equivalent to 3.71 mg of allicin per tablet did not significantly alter warfarin’s pharmacokinetics or pharmacodynamics. Use caution with doses > 7 g/day.

Antiplatelet drugs

Theoretically, a pharmacodynamic interaction is possible when using garlic at high doses in excess of usual dietary amounts, although a small clinical study involving 10 adult participants showed garlic had no effect on platelet function. Observe.

Antihypertensive agents

Theoretically, potentiation effects are possible when using garlic at high doses in excess of usual dietary amounts — this can be used as adjunctive therapy to produce beneficial results.

Antihyperlipidaemic agents

Theoretically, potentiation effects are possible when using garlic at high doses in excess of usual dietary amounts — this can be used as adjunctive therapy to produce beneficial results — observe.

Helicobacter pylori triple therapy

Additive effects are theoretically possible. While it is prudent to observe the patient for adverse reactions, the interaction may be beneficial.

Hepatotoxic drugs

Garlic may exert hepatoprotective activity against liver damage induced by drugs, according to in vitro tests, which suggests a beneficial interaction.

Paracetamol

In vivo protection from garlic and ajoene on paracetamol-induced hepatotoxicity has been observed— beneficial interaction.

CONTRAINDICATIONS AND PRECAUTIONS

Patients with bleeding abnormalities should avoid therapeutic doses of garlic. Although usual dietary intakes are likely to be safe prior to major surgery, suspend the use of high-dose garlic supplements 1 week before, as there is a theoretical increased risk of bleeding.

PREGNANCY USE

Garlic is not recommended at doses greater than usual dietary intakes.