INHIBITORY POTENTIAL OF CHEMICAL CONSTITUENTS FROM Paeonia suffruticosa AGAINST α-GLUCOSIDASE AND α-AMYLASE

Phytochemical study of the root bark of Paeonia suffruticosa plant led to the isolation and characterization of paeoniflorigenone (1), benzoylpaeoniflorin (2), betulinic acid (3), oleanolic acid (4), beta-sitosterol (5), and caffeic acid octadecyl ester (6). The enzymatic activities of compounds 1-6 were evaluated by in vitro inhibition assay of alpha-glucosidase and alpha-amylase. Compounds 1-6 with IC50 values ranging from 30 to 180 mu M inhibited alpha-glucosidase more efficiently than the standard compound acarbose (IC50 = 1463.0 +/- 29.5 mu M). Conversely, these compounds (with IC50 values ranging from 40 to 200 mu M) were less potent against alpha-amylase compared to acarbose (IC50 = 16.6 +/- 0.9 mu M). Kinetic analysis showed that compound 1 was a mixed-type inhibitor, compounds 3 and 4 were noncompetitive inhibitors, while compound 6 was an uncompetitive inhibitor of glucosidase.