Two new flavones from Rubus biflorus Buch

This project is to study chemical constituents of Rubus biflorus Buch (Chinese name “Fenzhimei”), isolated by silica gel chromatography and structure determined by spectroscopic techniques. Two flavones were isolated from Rubus biflorus Buch and identified as 8-methyl-6-(3″-methylbut-2″-enyl)-5,7-dihydroxy-5′-methoxy-3′,4′-methylenedioxy flavone (A) and 8-methyl-5-methoxy-6,7-(2″,2″-dimethylpyran)-3′,4′-methylenedioxy-5′-(3-methylbut-2-enyl) flavone (B), named as fenzhimines A and B, respectively. Compounds A and B are two new flavonoids.