塔拉豆荚中鞣质化合物及其抗氧化活性

目的:对塔拉豆荚中代表性鞣质化合物进行色谱制备及抗氧化活性评价。方法:对塔拉豆荚进行了提取、分离,利用现代色谱方法对化学成分进行结构鉴定,并用清除2,2-二苯基-1-苦肼基(DPPH)自由基法对提取物及所得鞣质化合物进行抗氧化活性测试。结果:从塔拉豆荚水提取物中得到了6个代表性鞣质化合物gallic acid(1),methyl gallate(2),ethyl gallate(3),methyl 3,5-di-O-galloylquinic acid(4),methyl 3,4,5-tri-O-galloylquinic acid(5),methyl 3,4,5-tri-O-galloylquinate(6)。该6种化合物经液质分析显示为塔拉中的主要鞣质类成分。抗氧化活性测试结果显示塔拉豆荚的水提物(Fr.1),甲醇提取物(Fr.2)以及6个鞣质化合物均有一定程度的抗氧化活性,其DPPH自由基清除能力15Fr.13维生素C6Fr.242。结论:塔拉豆荚提取物有较好的抗氧化活性,而鞣质化合物应为其抗氧化活性的主要物质基础。

Tannins in Pods of Tara and Their Antioxidant Activities

Objective: To perform chromatograph preparation and evaluate the antioxidant activity of the representative tannins from Tara pods.Method: The components of Tara (Caesalpinia spinosa) pods were isolated and purified, and their structures were identified by modern chromatography method. Their antioxidant activities of these fractions and compounds were investigated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method.Result: Six representative tannin compounds were isolated from the aqueous extract of the Tara pods and the structures were identified as gallic acid(1), methyl gallate(2), ethyl gallate(3), methyl 3, 5-di-O-galloylquinic acid(4), methyl 3, 4, 5-tri-O-galloylquinic acid(5), and methyl 3, 4, 5-tri-O-galloylquinate(6). High performance liquid chromatography mass spectrometry (HPLC-MS) results showed that the 6 compounds were the main tannin components in Tara. Antioxidant activity results showed that, aqueous extract (Fr. 1), methanol extract (Fr. 2) and 6 tannin compounds had certain antioxidant activities, and their DPPH free radical scavenging capability was in the following order:1 > 5 > aqueous extract > 3 > Vitamin C > 6 > methanolic extract > 4 > 2 .Conclusion: The extracts of Tara pods had good antioxidant activity, and the tannin compounds should be the main active antioxidant components.