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大蒜 (Garlic)
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。 命名 「蒜頭」多數人也會稱為「大蒜」。將其種在土壤中或淺水中,剛開始會長出有些像小蔥的綠色的嫩苗,有的地區將此嫩苗也稱為「大蒜」,但也有很多地區將此綠苗稱為「蒜苗」 ,還有地區稱此嫩苗為「蔥花」(如山東)。蒜頭繼續生長到開花期,會長出較硬的花柄托住上面的花,有的地區稱此花柄為「蒜苗」,但很多地區稱此花柄為「蒜薹」。 大蒜素 蒜含有大蒜素(allicin)。一般認為,大蒜素的產生過程是大蒜粉碎後它所含的不穩定的蒜氨酸(1)經蒜氨酶分解為烯丙次磺酸(2)和脫氫丙氨酸(3),然後不穩定的脫氫丙氨酸(3)立即分解為丙酮酸和氨,而烯丙次磺酸(2)則兩分子歧化為烯丙亞磺酸(4)與烯丙硫醇(5),它們繼續失水生成大蒜素(6)。 大蒜素功效 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。 當人體食用含有大蒜素的蔬菜後,在血液中會釋放一氧化氮,能令血管擴張,改善勃起功能障礙。用途:提純的大蒜素可用作抗菌藥、飼料添加劑、殺蟲劑和殺菌劑。 大蒜用途 本草綱目記載蒜可治療便毒諸瘡、產腸脫下、小兒驚風。現代醫學認為大蒜能提高免疫力,提高人體淋巴T細胞,巨噬細胞等免疫系統轉化能力。將新鮮的大蒜切片或搗碎後生吃有助於心臟健康。醫學上被用來驅除腸內的寄生蟲。 中國醫藥大學生物科技系教授鍾景光和醫學系副教授楊家欣以癌細胞研究的相關論文榮獲湯森路透科學卓越研究獎。鍾景光指出,大蒜中的有機硫化合物能有效抑制大腸癌細胞,而他們的研究完整釐清大蒜中抗癌成分對癌細胞的影響過程,得知抗癌成分如何讓癌細胞週期停滯,直到死亡的過程,提供大腸癌藥物研發的參考依據。 一般的大白蒜在經過發酵後會成為黑蒜,其蒜素的濃度是一般大白蒜的20倍。 (蒜你狠) |
Garlic (大蒜)
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." |