Structural Elucidation and Antioxidant Activities of Proanthocyanidins from Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Leaves |
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Authors: | Yu Fu Liping Qiao Yuming Cao Xiaozhou Zhou Yu Liu Xingqian Ye |
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Affiliation: | 1. Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Fuli Institute of Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, Zhejiang University, Hangzhou, PR China.; 2. College of Life Science, Zhejiang University, Hangzhou, China.; National Cancer Institute at Frederick, United States of America, |
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Abstract: | Proanthocyanidins in Chinese bayberry leaves (PCBLs) were qualitatively analyzed. NMR data suggest that PCBLs are mostly composed of (epi)gallocatechin gallate units. Matrix-assisted laser desorption time-of-flight MS data indicate 95 possible prodelphinidin structures, ranging from dimers to tridecamers. Preparative normal-phase HPLC and further analysis by reverse-phase HPLC together with electrospray ionization MS enabled detection of 20 compounds, including seven newly identified compounds in Chinese bayberry leaves. The antioxidant capacity of PCBLs was evaluated by (1,1-diphenyl-2-picryl-hydrazyl), ferric-reducing antioxidant power, and oxygen radical absorption capacity assays. The EC50 of DPPH radical scavenging activities (as 50% decrease in the initial DPPH concentration) were 7.60 µg. The FRAP and ORAC values were 8859.33±978.39 and 12991.61±1553.34 µmol Trolox equivalents per gram, respectively. The results indicate the high antioxidant potency of PCBLs. |
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