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蒜 (Allium sativum) 亦名大蒜。底下鱗莖味道辣，有刺激性氣味，稱為「蒜頭」，可作調味料，亦可入藥。蒜葉稱為青蒜或蒜苗，花薹稱為蒜薹，均可作蔬菜食用。蒜是多年生宿根草本植物，葉狹長而扁平，淡綠色，表面有蠟粉；地下鱗莖由灰白色的膜質外皮包裹，內有小鱗莖，叫蒜瓣，由莖盤上每個葉腋中的腋芽膨大而成。
研究顯示大蒜素有抗菌、抗真菌、消炎、抗氧化、抗血栓、降血壓、維持脂蛋白平衡、防治動脈硬化等功效。 2009年，Vaidya、Ingold 和Pratt 的研究表明大蒜素的生物功效主要是由大蒜素分解產生的2-丙烯次磺酸造成的，該化合物不穩定，很快便與體內的自由基發生反應使之失活。
Garlic (Allium sativum) is a species in the onion genus, Allium. Its close relatives include the onion, shallot, leek, chive, and rakkyo. With a history of human use of over 7,000 years , garlic is native to central Asia, and has long been a staple in the Mediterranean region, as well as a frequent seasoning in Asia, Africa, and Europe. It was known to Ancient Egyptians, and has been used for both culinary and medicinal purposes.
Medicinal use and health benefits
In in-vitro studies, garlic has been found to have antibacterial, antiviral, and antifungal activity. However, these actions are less clear in vivo. Garlic is also claimed to help prevent heart disease (including atherosclerosis, high cholesterol, and high blood pressure) and cancer. Animal studies, and some early research studies in humans, have suggested possible cardiovascular benefits of garlic. A Czech study found garlic supplementation reduced accumulation of cholesterol on the vascular walls of animals. Another study had similar results, with garlic supplementation significantly reducing aortic plaque deposits of cholesterol-fed rabbits. Another study showed supplementation with garlic extract inhibited vascular calcification in human patients with high blood cholesterol. The known vasodilative effect of garlic is possibly caused by catabolism of garlic-derived polysulfides to hydrogen sulfide in red blood cells (RBCs), a reaction that is dependent on reduced thiols in or on the RBC membrane. Hydrogen sulfide is an endogenous cardioprotective vascular cell-signaling molecule.
A randomized clinical trial funded by the National Institutes of Health (NIH) in the United States and published in the Archives of Internal Medicine in 2007 found the consumption of garlic in any form did not reduce blood cholesterol levels in patients with moderately high baseline cholesterol levels.
According to Heart.org, "despite decades of research suggesting that garlic can improve cholesterol profiles, a new NIH-funded trial found absolutely no effects of raw garlic or garlic supplements on LDL, HDL, or triglycerides. The findings underscore the hazards of meta-analyses made up of small, flawed studies and the value of rigorously studying popular herbal remedies". In an editorial regarding the initial report's findings, two physicians from Weill Cornell Medical College of Cornell University, pointed out that there may "be effects of garlic on atherosclerosis specifically that were not picked up in the study".
However, a 2012 meta-analysis of randomized, double-blind, placebo-controlled trials looking at the effects of garlic on serum lipid profiles, found garlic was superior to placebo in reducing serum total cholesterol and triglyceride levels. Compared with the placebo groups, serum total cholesterol and triglyceride levels in the garlic groups was reduced by 0.28 (95% CI, -0.45, -0.11) mmol L⁻¹ (P = 0.001) and 0.13 (95% CI, -0.20, -0.06) mmol L⁻ ¹ (P < 0.001), respectively.
Allium sativum has been found to reduce platelet aggregation and hyperlipidemia.
In 2007, the BBC reported Allium sativum may have other beneficial properties, such as preventing and fighting the common cold. This assertion has the backing of long tradition in herbal medicine, which has used garlic for hoarseness and coughs. The Cherokee also used it as an expectorant for coughs and croup. However, in contrast to these earlier claims concerning the cold-preventing properties of garlic, a 2012 report in the Cochrane Database of Systematic Reviews concludes that "there is insufficient clinical trial evidence regarding the effects of garlic in preventing or treating the common cold. A single trial suggested that garlic may prevent occurrences of the common cold but more studies are needed to validate this finding. Claims of effectiveness appear to rely largely on poor-quality evidence ."
Garlic is also alleged to help regulate blood sugar levels. Regular and prolonged use of therapeutic amounts of aged garlic extracts lower blood homocysteine levels and has been shown to prevent some complications of diabetes mellitus. People taking insulin should not consume medicinal
amounts of garlic without consulting a physician.
Garlic was used as an antiseptic to prevent gangrene during World War I and World War II. More recently, it has been found from a clinical trial that a mouthwash containing 2.5% fresh garlic shows good antimicrobial activity, although the majority of the participants reported an unpleasant taste and halitosis.
Garlic cloves are used as a remedy for infections (especially chest problems), digestive disorders, and fungal infections such as thrush. Garlic can be used as a disinfectant because of its bacteriostatic and bacteriocidal properties.
Garlic has been found to enhance thiamin absorption, and therefore reduces the likelihood for developing the thiamin deficiency beriberi.
In 1924, it was found to be an effective way to prevent scurvy, because of its high vitamin C content.
Garlic has been used reasonably successfully in AIDS patients to treat Cryptosporidium in an uncontrolled study in China. It has also been used by at least one AIDS patient to treat toxoplasmosis, another protozoal disease.
Garlic supplementation has been shown to boost testosterone levels in rats fed a high protein diet.
A 2010 double-blind, parallel, randomised, placebo-controlled trial, involving 50 patients whose routine clinical records in general practice documented treated but uncontrolled hypertension, concluded, "Our trial suggests that aged garlic extract is superior to placebo in lowering systolic blood pressure similarly to current first line medications in patients with treated but uncontrolled hypertension."