| |
[摘要]：Peroxidase extracted from Momordica charantia catalyzed the H2O2-dependent oxidative coupling of 7-hydroxy-4-methylcoumarin to form four new dimers (1-4) and two known ones (S, 6). The structures, including the absolute configurations of axially chiral compounds, were unambiguously characterized by NMR spectroscopy, online HPLC-CD, and a variety of computational methods. Bioactive experiments demonstrated that compounds 1 and 2 had significant inhibitory effects on yeast a-glucosidase, much better than the controls. Noncompetitive binding mode was found by the graphical analysis of steady-state inhibition data. The mechanism of enzymatic inhibition confirmed in some depth that the inhibitors altered the secondary structure of alpha-glucosidase by decreasing the alpha-helix and increasing the beta-sheet content. In summary, bicoumarins 1 and 2 might be exploited as the lead compounds for further research of antidiabetic agents, and this research provided a "green" method to synthesize compounds with the chiral biaryl axis generally calling for multistep reactions in organic chemistry. |
|
