Research On The Basis Material Of Antioxidant Activitiesin Hawk Tea

Hawk tea, Litsea coreana L., has a long drinking history in folk for its effects of detoxification and detumescence, studies have shown that those effects were exerted through anti-oxidation, anti-viral, anti-inflammatory, but the basis material and mechanism about it is still not clear.Hawk tea was chose as the research object, from the aspects of natural products scavenging free radicals, methods of combination of in vitro and in vivo experiments, detection of physiological and biochemical index combined with modern biotechnology were applied to screen the effective targeted position of hawk tea’s antioxidant functions and to detect the basis material which may achieve the anti-oxidative abilities. The results are as follows:1) According to the previous results Ya’an hawk tea was selected to be the research material. The dry hawk tea leaves were initially extracted with 70% ethanol and then fractionated by petroleum ether chloroform, ethyl acetate, n-butanol, sequentially. Macroporous resin technology was applied to further separation with ethyl acetate and n-butanol fraction which contains higher external anti-oxidant activities. It indicated 10% alcohol elution of ethyl acetate phase(E1) had the strongest antioxidant capacities. HPLC detection results showed that the primary material in E1 was catechins, which account for 70.10%.2) Antioxidant index DPPH, ion reducing power, OH-·scavenging were detected and total contents of flavonoids and phenolics those were compared among Xuancheng, Meitan, Daozhen and Ya’an four hawk teas. Results showed that the contents of bioactive compounds flavonoids and phenolic had a high positive correlation with in vitro anti-oxidative abilities. LC/MS analysis indicated catechin, hyperin, isoquercitrin, astragalin, quercetin were the major active components in hawk tea extracts but different in contents. Daozhen,Meitan hawk tea contain higher contents of catechin and astragalin.3) CCl4 actue hepatic injury animal model was built to evaluate the liver protection effects of hawk tea extracts.Results indicated SOD,GSH enzyme activities increased and MDA contents decreased compared with the model group, the ethyl acetate fraction group exhibit the best in vivo antioxidant effect besides the catechin group.4) The senility-delaying effects of hawk tea extracts were researched by using D-galactose aging mouse model, differences level of SOD, GSH,MDA were integrated investigated in liver, heart, brain, kindey,lung mice organ. Results showed that hawk tea extracts delayed aging progress, besides the catechin group, the ethyl acetate fraction group showed the most obvious effects.In conclusion,the hawk tea extraction had potential antioxidant capacities, the ethyl acetate extract fraction show the highest antioxidant ability. Correlation analysis and HPLC detection indicated that catechin may be the primary substance to exert in vitro and in vivo antioxidant activities.