Effect of flavonoids from Exellodendron coriaceum (Chrysobalanaceae) on glucose-6-phosphatase

From the n-butanol ext. of the aerial parts of Exellodendron coriaceum (Benth.) Prance the flavonoids quercetin-3-O-β-D-galactopyranoside (1), quercetin-3-O-α-L-arabinopyranoside (2), quercetin-3-O-α-L-rhamnopyranosyl-(1→2)-α-L- rhamnopyranoside (3), and quercetin-3-O-α-L-rhamnopyranosyl-(1→6)-β-D- galactopyranoside (4) were isolated. Addnl. from this ext. 3 flavonoids were isolated and partially characterized as quercetin glycosides. All these compds. were tested for their hypoglycemic activity using the glucose-6-phosphatase microsomal hepatic system. The flavonoids inhibited the activity of the enzyme when intact microsomes were used, the highest percentage of inhibition being 65%. To the best of our knowledge, this is the 1st report of chem. and biol. activity of E. coriaceum.