| Garlic（Allium Sativum L.） is a member of liliaceous plant and the underground bulb of the garlic. Garlic is known as natural antibiotics and it has been widely used as food and medicine for a long time. Modern research shows that garlic possesses various pharmacological activities such as antibacterial, antithrombosis, antitumor, lipid-lowering, lowering blood sugar, liver protection and so on. For the purpose of comprehensive utilization of garlic resources, garlic liposouble components were studied on the bioactivity determination, isolation and identification. Furthermore, garlic protein extracted from residues a by-product of liposouble components were studied by optimization the extraction producer by response surface methodology（RSM）, and the bioactivity and functional propertites were also investigated.Firstly, the contents of polyphenol and in vitro antioxidant activities of different polar fractions（ethanol extract, petroleum ether, ethyl acetate, n-butanol and water fractions） of garlic were comparatively studied. The n-butanol fraction of garlic had the highest content of polyphenol and showed the most potent DPPH radical scavenging activity and ferric reducing power activity, while the petroleum ether fraction showed the highest inhibitory effect on lipid peroxidation induced by Fe2+-Vc. To clarify the relationship between the activities and the constituents, the garlic farctions were analyzed by GC-MS. Tewelve compounds were identified and eight of them were sulfur compounds according to the NIST data. A variety of separation and purification methods（normal phase silica chromatography, gel column chromatography, recrystallization etc） were performed for the separation and purification of petroleum ether and ethyl acetate fractions. Fifteen compounds were obtained and six of them were identified by 1H-NMR. They were sitosterol（1）, ergosterin（2）, daucosterol（7）, apigenin（11）, luteolin（12）, quercetin（13）.Secondly, a new method for preparation of green garlic was developed in this study. The chemical and physical properties of garlic green pigment were investigated. The pigment was purified by a series of coloum chromatography. The antioxidant activity of the purified pigment was determined and garlic blue pigment（GBP） showed better antioxidant activity. Two main compounds of the yellow pigment（GYP） were identified as C24H28N2O2S（Mw 408） and C16H10N2O4（Mw 294）, respectively. One main compound of GBP was identified as C16H10N2O2S（Mw 294）.Finally, ultrasonic assisted extraction procedure was employed to extract garlic protein from the defatted gailic residues. The Box-Behnken design（BBD） was applied to optimize the extraction conditions. The optimal conditions were solvent-to-sample of 27.5:1, alkali concentration of 0.147 mol/L and extraction time of 70 min. The yield of the protein was 101.86 mg/g under the optimized condition. The pepsin and trypsin digestion products of garlic protein showed better antioxidant activities, angiotensin i-converting enzyme inhibitory（ACEI） activities and they also showed better antihypertension effects in spontaneously hypertensive rats when compared with garlic protein. |
