Structure-activity studies of flavonoids as inhibitors of hyaluronidase.

The order of decreasing potency for five most potent flavonoids as inhibitors of hyaluronidase was found to be: condensed tannin less than luteolin less than apigenin less than kaempferol less than silybin. Kinetic studies of these inhibitors showed that their mode of inhibition was competitive. Aglycones were stronger inhibitors than their corresponding glycosides. The following flavonoid structure conferred potent inhibitory effect: a double bond between carbons 2 and 3; unsubstituted hydroxyl groups at positions 5, 7 and 4' and a ketone group at position 4.