黑茶金花体外抗氧化及降血脂活性研究

目的 探究黑毛茶、发花黑茶、去花茶底和纯金花主要品质成分含量及其体外抗氧化、降血脂活性差异。方法 以黑毛茶为原料, 采用传统黑茶发花工艺制成金花黑茶, 分离金花后获得黑毛茶、金花黑茶、去花茶底和纯金花4个样品, 分析其主要品质成分含量、体外抗氧化及降血脂活性差异。结果 相比黑毛茶、金花黑茶和去花茶底, 纯金花的水浸出物、可溶性糖和游离氨基酸含量显著升高(P<0.05), 黄酮类物质含量则显著降低(P<0.05) 多酚类物质含量表现为黑毛茶>去花茶底>金花黑茶>纯金花;各样品对1,1-二苯基-2-三硝基苯肼自由基(DPPH)、亚硝基、超氧阴离子自由基清除能力和总还原能力表现为黑毛茶>去花茶底>金花黑茶>纯金花，去花茶底对羟基自由基的清除能力最强; 同时通过分析4个样品体外结合胆酸盐能力、对胰脂肪酶活性的激活能力及对胆固醇酯酶的抑制能力发现, 去花茶底的体外降血脂效果最佳, 其次是金花黑茶(P<0.05)。相关性分析显示, 多酚含量与超氧阴离子清除能力呈显著正相关(P<0.05);黄酮总量与DPPH清除能力、亚硝基清除能力、总还原力和胰脂肪酶激活率呈显著正相关(P<0.05)。结论 金花黑茶发花产物中的抗氧化及降血脂活性物质主要集中在去花茶底中。

Study on antioxidant and hypolipidemic activity in vitro of post-flowering dark tea

Objective To explore the differences in content of main quality components and their antioxidant and hypolipidemic bioactivity in vitro of namely dark tea, post-flowering dark tea, post-flowering isolated leaf base and pure gold flower. Methods Post-flowering dark tea was prepared by traditional dark tea flowering processing technology with namely dark tea as raw material, 4 samples of namely dark tea, post-flowering dark tea, post-flowering isolated leaf base and pure gold flower were obtained after separation of gold flower. Then the content of main quality components, antioxidant and hypolipidemic bioactivity in vitro were detected and analyzed. Results Compared with namely dark tea, post-flowering dark tea and post-flowering isolated leaf base, the content of water extract, soluble sugar and free amino acid of pure gold flower were significantly increased (P<0.05), while the content of flavonoids was significantly decreased (P<0.05), the content of tea polyphenols was as follows: Dark tea>post-flowering isolated leaf base>post-flowering dark tea>pure gold flower; the scavenging abilities of each sample to 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical, nitroso, superoxide anion radical and total reducing power kept the trend of dark tea>post-flowering isolated leaf base>post-flowering dark tea>pure gold flower, and the hydroxyl radical scavenging ability of post-flowering isolated leaf base was the strongest. At the same time, by analyzing the cholate binding ability, the activation ability of pancreatic lipase activity and the inhibition ability of cholesterol esterase in vitro of the 4 samples, it was found that the removal of post-flowering isolated leaf base had the best hypolipidemic bioactivity, followed by post-flowering dark tea (P<0.05). Correlation analysis showed that tea polyphenols content was positively correlated with superoxide anion radical scavenging ability (P<0.05). The total flavonoids were significantly positively correlated with DPPH radical scavenging ability, nitroso scavenging ability, total reducing power and pancreatic lipase activation rate (P<0.05, P<0.01). Conclusion The substances with antioxidant and hypolipidemic activity in the flower products of post-flowering dark tea are mainly concentrated in post-flowering isolated leaf base.