Tab. II.

The biological activities of garlic and its active components as shown by clinical trials.

Bioactivities	Subjects/ patients	Study design	Interventions and duration	Results	References
Antioxidant properties	92 obese patients	Placebo-controlled randomized double-blind trial	400 mg of garlic extract per day for 3 months	Enhanced production of antioxidant	[24]
	46 untrained boys	Randomized controlled trial	250 mg garlic capsule per day for 8 weeks	Lowered oxidative stress and enhanced resistance and endurance during training	[25]
	44 pregnant women	Placebo-controlled randomized double-blind trial	1 mg of allicin plus 400 mg garlic per day for 9 weeks	Reduced oxidative stress	[26]
	42 menopausal women	Randomized double-blind controlled trial	1200 μg allicin per day for one year	Reduced oxidative stress	[27]
Anti-inflammatory properties	120 healthy individuals	Placebo-controlled randomized double-blind parallel intervention study	2.56 g aged garlic extract (AGE) per day for 90 days	Enhanced immune system functions	[28]
	120 healthy subjects	Randomized double-blind placebo-controlled nutrition intervention	2.56 g aged garlic extract per day for 90 days	Improved immune system function, less cold and flu symptoms	[29]
	60 healthy volunteers	Randomized controlled trial	1 g to 3 g of garlic powder 6.0 and 24.0 h respectively	Immunostimulatory effect	[30]
	51 healthy but obese adults	Placebo-controlled double-blind randomized trial	3.6 g aged garlic extract per day for 6 weeks	Reduced inflammation	[31]
Lipid lowering effects	160 type 2 diabetic patients	Randomized control trial	500 mg of garlic powder and 1.1 mL of olive oil for 3 months	Prevented dyslipidaemia	[32]
	150 hyperlipidaemic patients	Single-blind placebo-controlled study	1 mg allicin and 400 mg garlic in tablet, twice daily for 6 weeks	Lowered lipid levels	[33]
	75 healthy adults	Placebo-controlled randomized double-blind trial	10.8 mg allicin (3 garlic cloves) per day for 12 weeks	Lipid-lowering effects	[34]
	70 diabetic patients with dyslipidaemia	Placebo controlled randomized single-blind study	Garlic tablet 300 mg, 2 times daily for 12 weeks	Improvements in dyslipidaemia	[35]
Antidiabetic effects	210 type 2 diabetes mellitus patients	Placebo-controlled single-blind study	Garlic tablet 300-1500 mg per day plus Metformin 500 mg twice a day for 24 weeks	Reduced HbA1c and fasting blood glucose levels	[36]
	Two 38-subject groups having diabetes	Double blind trial	750 mg capsule containing onion and garlic 20% (w/w), nettle leaf 20% (w/w), berry leaf 10% (w/w), walnut leaf 20% (w/w), fenugreek seed 20% (w/w), and cinnamon bark 10% (w/w), thrice daily for 12 weeks	Decreased HbA1c and fasting blood sugar level.	[37]
Bone diseases	80 overweight or obese postmenopausal women with knee osteoarthritis (OA)	Placebo-controlled parallel-design randomized double-blind trial	500 mg garlic tablet twice daily for 12 weeks	Improved OA symptoms	[38]
	76 overweight or obese postmenopausal women	Placebo-controlled randomized double-blind parallel design trial	1000 mg garlic tablet per day for 12 weeks	Reduced pain severity	[39]
	44 postmenopausal osteoporotic women	Double-blind randomized controlled clinical trial	2 garlic tablets per day for 8 months	Immunomodulatory effects	[27]
Antimicrobial effects	45 children	Randomized double-blind controlled clinical trial	2 mL garlic or garlic with lime formulation, used as mouth rinse, once a day for 2 weeks	Economic and effective alternative to sodium fluoride mouth rinse	[40]
Antiviral effects on respiratory viral infections	796 children	Double-blind placebo-controlled randomized trial	First stage Allicor 600 mg and second stage Allicor 300 mg tablets per day for 5 months	Effective in the prevention of nonspecific acute respiratory infections, without any side effects	[41]
Anticancer effects	57,560 men and women	Comparison-based study	One bulb of garlic per day for 9 years	Reduced risk of colorectal adenoma	[42]
	1,424 lung cancer cases and 4,543 healthy controls	Population-based case control study	Weekly administration of 8.4 g raw garlic or 33.4 g garlic components for 7 years	Dose-dependent protective association between raw garlic and lung cancer	[43]
	5,033 patients with gastric cancer (aged 35-74 years)	Double-blind intervention study	Synthetic allitridum 200 mg daily and 100 μg selenium every other day for 1 month per year, for a total of 3 years	Protection from gastric cancer	[44]
	3,365 H. pylori positive volunteers, with participants and risk for gastric cancer	Placebo-controlled blinded randomized trial	200 mg aged garlic extract and 1 mg steam distilled garlic oil 2, twice daily for 7.3 years	Decreased incidence of gastric cancer and mortality	[45]
Cardioprotective effects	157 postmenopausal asymptomatic women	Placebo-controlled double-blind clinical trial	Garlic herbal preparation containing 500 mg isoflavonoid for 12 months	Suppression and prevention of atherosclerosis	[46]
	92 obese patients	Placebo-controlled randomized double-blind nutritional intervention	Daily intake of 400 mg of garlic extract for 3 months	Suppressed inflammation and improved endothelial biomarkers of cardiovascular problems	[24]
	60 patients with mild hypercholesterolemia	Randomized controlled trial	6 g of aged black garlic twice a day for 12 weeks	Enhanced cardioprotective effects, beyond gold standard medication	[47]
	55 patients with metabolic syndrome	Randomized double-blind study	AGE 2400 mg daily for 52 weeks	Decreased low attenuation plaque (LAP) formation in coronary arteries	[48]
	51 coronary heart disease patients	Placebo-controlled randomized double-blinded study	150 mg Allicor garlic tablet 2 times per day for 12 months	Significant reduction in cardiovascular risk, by 1.5-fold in men (p < 0.05) and 1.3-fold in women	[49]
Antihypertensive effects	100 hyperlipidemic patients	Randomized study	Mixture of garlic and coriander, 2 g daily for 60 days	Improved lipid parameters and reduced blood pressure	[50]
	79 patients with uncontrolled systolic blood pressure	Dose-response trial	AGE 240/480/960 mg containing 0.6/1.2/2.4 mg of S-allylcysteine daily for 12 weeks	Marked reduction in systolic blood pressure	[51]
	41 moderately hypercholesterolemic patients	Double-blind crossover study	AGE 7.2 g daily for 10 months	Reduced systolic and diastolic blood pressure	[52]