Inhibition of Xanthine Oxidase by Rhodiola crenulata Extracts and Their Phytochemicals
Inhibition of Xanthine Oxidase by Rhodiola crenulata Extracts and Their Phytochemicals
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DOI：
10.1021/jf5004094
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发表时间：
2014-04-30
影响因子：
6.1
通讯作者：
Hsieh, Jung-Feng
中科院分区：
文献类型：
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作者：
Chu, Yung-Hung;Chen, Chao-Jung;Hsieh, Jung-Feng
采用分级分离技术，从红景天提取物中分离出4种植物化学成分。经质谱和核磁共振波谱鉴定为4‘-羟基苯乙酮(4-HAP)、表儿茶素-(4-β，8)-表儿茶素没食子酸酯(B2-3’-O-没食子酸酯)、红景天苷和对酪醇。然后评价了这些纯化化合物对黄嘌呤氧化酶(XO)活性的抑制作用，并与已知的XO抑制剂(别嘌醇；IC50=12.21+/-0.27µM)进行了比较。4-HAP和B2-3‘-O-没食子酸酯对XO均有抑制作用，其半数抑制浓度(IC50)分别为15.62+/-1.19和24.24+/-1.80 mU/M。而红景天苷和酪醇在30mU时对XO没有明显的抑制作用。此外，抑制动力学研究表明，4-HAP和B2-3‘-O-没食子酸酯是混合竞争性抑制剂。4-HAP和B2-3‘-O-没食子酸酯的抑制常数(K-I)分别为8.41+/-1.03和6.16+/-1.56mU/M。这些结果表明，4-HAP和B2-3‘-O-没食子酸酯是有效的XO抑制剂。
Using a fractionation technique, four phytochemicals were isolated from Rhodiola crenulata extracts. These compounds were identified as 4'-hydroxyacetophenone (4-HAP), epicatechin-(4 beta,8)-epicatechin gallate (B2-3'-O-gallate), salidroside, and p-tyrosol using mass spectrometry and nuclear magnetic resonance spectroscopy. The inhibition of xanthine oxidase (XO) activity by these purified compounds was then evaluated and compared to that of a known XO inhibitor (allopurinol; IC50 = 12.21 +/- 0.27 mu M). Both 4-HAP and B2-3'-O-gallate showed an XO inhibitory effect, for which the half maximal inhibitory concentration (IC50) values were 15.62 +/- 1.19 and 24.24 +/- 1.80 mu M, respectively. However, salidroside and p-tyrosol did not show significant inhibitory effects on XO at 30 mu M. Furthermore, an inhibition kinetics study indicated that 4-HAP and B2-3'-O-gallate are mixed competitive inhibitors. The inhibition constants (K-i) of 4-HAP and B2-3'-O-gallate were 8.41 +/- 1.03 and 6.16 +/- 1.56 mu M, respectively. These results suggest that 4-HAP and B2-3'-O-gallate are potent XO inhibitors.