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Resveratrol,3,4’,5-trihydroxystilbene, is a phytoalexin found in grapes, Polygonum Cuspidatum and other plants. In recent years, this polyphenol has attracted the attention of researchers because of its remarkable therapeutic potential including chemoprevention of cancer, inflammation, cardiovascular diseases. In addition, reseveratrol shows antioxidant, antibacterial and antifungal activities.This study examined the content of resveratrol in peanuts and Polygonum Cuspidatum, and optimized the extraction process of resveratrol from Polygonum Cuspidatum. The mono-factor design was carried out to determine the effects of extracting methods, extracting solution, solid-liquid ration, extracting time, temperature and ethanol volume fraction on the extraction rate of resveratrol, and the factors having a major impact were optimized by a response surface method. The results showed that the optimum conditions were extracting time of 1.1h, temperature of 53℃and ethanol volume fraction of 79%. Under these conditions, the measured extraction rate was 5.912 mg/g, which was close to the predicted value of 5.918mg/g.The further purification of resveratrol was performed with silica column chromatography. The resveratrol content in purified product was up to 99.8%, and the overall yield of resveratrol was 0.3%. The final sample was characterized by HPLC, FT-IR, UV-vis, ESI-MS,1HNMR, and was identified to be trans-resveratrol.This paper also studied the stability, antioxidant, antibacterial and antifungal activities of trans-resveratrol. Experiments indicated that trans-resveratrol was steady well at 4-50℃or in many metal ionic solution, and 120 mg/kg trans-resveratrol had great antioxidant activity in oil. In addition,trans-resveratrol had good antibacterial efficiency. Inhibitory rate of resveratrol on Staphylococcus aureus was 80%when the concentration was 0.125mg/mL; Inhibitory rate of resveratrol on Escherichia coli was 40%when the concentration was 1.00mg/mL after 10 hours.
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