苦丁茶提取物多酚含量与抗氧化活性的测定

首先用不同的有机溶剂分部萃取苦丁茶(Ilex kudincha C.J.Tseng)热水提取物(粗提物),得到氯仿萃取物、乙酸乙酯萃取物、正丁醇萃取物及萃取剩余物,然后采用Folin-Ciocalteu比色法测定粗提物和各萃取物的多酚含量,同时应用DPPH法、TEAC法和FRAP法分别测定粗提物和各萃取物的自由基清除能力和还原Fe3+能力。结果表明,苦丁茶提取物具有较高的多酚含量和较强的抗氧化能力;DPPH法和FRAP法测定各提取物抗氧化能力的结果为乙酸乙酯萃取物>正丁醇萃取物>粗提物>萃取剩余物>氯仿萃取物,TEAC法测定结果为乙酸乙酯萃取物>正丁醇萃取物>粗提物>氯仿萃取物>萃取剩余物;多酚含量与抗氧化能力之间、所用抗氧化测定方法之间均存在较好的相关性。

Determination of Polyphenolic Content and Antioxidant Activity of Kudingcha Made from Ilex kudincha C. J. Tseng

The hot water extract (crude extract) of kudingcha made from Ilex kudincha C. J. Tseng and its four fractions of chloroform, ethyl acetate, n-butanol, and water were prepared. The total polyphenol contents and the antioxidant activity of the extracts were determined by Folin-Ciocalteu method and DPPH assay, FRAP assay, and TEAC assay, respectively. The results showed that kudingcha extracts contained high polyphenol content and showed potent antioxidant activity. The antioxidant activities of crude extract and its fractions decreased in the order of ethyl acetate fraction>butanol fraction>crude extract>water fraction>chloroform fraction according to the DPPH assay and FRAP assay, which were the same with the exception of the rank order of water fraction and chloroform fraction obtained from TEAC assay. Satisfactory correlations between the total polyphenol content and antioxidant activity and between measuring methods of antioxidant activity were observed. It suggests that the polyphenols in the extracts are largely responsible for the antioxidant activities.