Isolation and identification of novel alpha-amylase inhibitors from Euonymus laxiflorus Champ.

摘要

Euonymus laxiflorus Champ. (ELC) has been reported to possess potential antidiabetic activity. The aim of this study is to isolate and identify the active compounds in ELC extract. Application of effective techniques including Diaoin, octadecylsilane opened columns, dialysis, and preparative high-performance liquid chromatography (HPLC) coupled with a biologically guided assay resulted in isolation of 11 novel active compounds. Five compounds were identified as new alpha-amylase inhibitors (alpha AIs), viz. walterolactone A/B beta-d-pyranoglucoside (1), schweinfurthinol 9-O-beta-d-pyranoglucoside (10), 1-O-(3-methyl)-butenoyl-myo-inositol (11), leonuriside (13), and (3,5-dimethoxy-4-hydroxyphenol) -1-O-beta-d-(6'-O-galloyl)-glucopyranoside (21). Among these inhibitors, three compounds (1, 10, 11) were characterized as new. Another six known compounds (2, 9, 16, 17, 18, 19) were determined as phenolic. Notably, six compounds (1, 2, 9, 13, 16, 17) demonstrated significant activity, comparable to or higher than that of acarbose, a commercial antidiabetic drug, based on t test ranking. The relationship between the chemical structures and bioactivity of the inhibitors is also reported.