Kinetic analysis of inhibition of α-glucosidase by leaf powder from Morus australis and its component iminosugars
Kinetic analysis of inhibition of α-glucosidase by leaf powder from Morus australis and its component iminosugars
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DOI：
10.1080/09168451.2020.1783991
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发表时间：
2020-07-12
影响因子：
1.6
通讯作者：
Yasukawa, Kiyoshi
中科院分区：
文献类型：
--
作者：
Qiao, Ying;Nakayama, Juri;Yasukawa, Kiyoshi
桑葚含有抑制α-葡糖苷酶的亚胺糖，如1-脱氧野尻霉素（1-DNJ）、荞麦碱和2-O-α-D-吡喃半乳糖基脱氧野尻霉素（GAL-DNJ）。本研究对桑叶中的亚氨基糖进行了定量分析，并对α-葡萄糖苷酶水解麦芽糖进行了动力学分析。通过LC-MS/MS，粉末叶中1-DNJ、荞麦碱和GAL-DNJ的浓度分别为4.0、0.46和2.5 mg/g，而烘烤叶中的浓度分别为1.0、0.24和0.73 mg/g，表明烘烤过程降解了亚胺糖。稳态动力学分析表明，粉末和烤叶表现出竞争性抑制。在pH6.0、37 ℃条件下，煮制粉末和烘烤叶提取物的IC（50）值分别为0.36和1.1mg/mL。在相同条件下，1-DNJ、荞麦碱和GAL-DNJ的IC（50）值分别为0.70 μ g/mL、0.18 mg/mL和2.9 mg/mL。这些结果表明，在M. australis，1-DNJ是α-葡糖苷酶的主要抑制剂。
Mulberry leaves contain iminosugars, such as 1-deoxynojirimycin (1-DNJ), fagomine, and 2-O-alpha-D-galactopyranosyl deoxynojirimycin (GAL-DNJ) that inhibit alpha-glucosidase. In this study, we quantified iminosugars inMorus australisleaves and made the kinetic analysis in the hydrolysis of maltose by alpha-glucosidase. By LC-MS/MS, the concentrations of 1-DNJ, fagomine, and GAL-DNJ in the powdered leaves were 4.0, 0.46, and 2.5 mg/g, respectively, and those in the roasted ones were 1.0, 0.24, and 0.73 mg/g, respectively, suggesting that the roasting process degraded iminosugars. Steady-state kinetic analysis revealed that the powdered and roasted leaves exhibited competitive inhibition. At pH 6.0 at 37oC, the IC(50)values of the extracts from the boiled powdered or roasted leaves were 0.36 and 1.1 mg/mL, respectively. At the same condition, the IC(50)values of 1-DNJ, fagomine, and GAL-DNJ were 0.70 mu g/mL, 0.18 mg/mL, and 2.9 mg/mL, respectively. These results suggested that inM. australis, 1-DNJ is a major inhibitor of alpha-glucosidase.