Study on the antioxidant activity of tea flowers (Camellia sinensis)
Major chemical compounds in different extracts from tea flowers (Camellia sinensis) were analyzed. Distilled water or 70％ ethanol extracts were then fractionated with chloroform, ethyl acetate and n-butanol, respectively.Each extract fraction was tested its scavenging activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals. The results showed that ethyl acetate fraction of ethanol-extract of tea flower (EEA) exhibited the highest quenching activity to hydroxyl radicals (SC5011.6 μg/ml), followed by ethanol-extract (EE) of tea flower (SC50 19.7μg/ml). Same tea flower extract showed big different scavenging activities on different free radicals.EEA quenched 80％ of hydroxyl radicals generated by Fentons reaction, however, only 40％ of DPPH radical was scavenged in the Fe(Ⅱ)-H2O2 -luminol system. The contents of flavones, polyphenols and catechins in EE and EEA fractions were higher than those in other fractions. We suggest that the stronger scavenging abilities to free radicals might be due to polyphenols, EGCG, ECG and flavones. However, the water extracts of tea flower and their fractions showed lower antioxidant activity for their inhibitory effect on hydroxyl radicals and DPPH radicals.
tea flower antioxidant activity DPPH hydroxyl radical chemiluminescence
Ziying Yang Yi Xu Guoliang Jie Puming He Youying Tu
Department of Tea Science, Zhejiang University, Hangzhou, China
国际会议
国际营养科学联盟第八届临床营养学大会暨第五届亚太临床营养学会大会
杭州
英文
148-152
2006-10-01（万方平台首次上网日期，不代表论文的发表时间）