Hydrophilic flavonoid components of leaves and flower heads of polygonum senegalense and the larvicidal and antifeedant activities of its hydrophobic principles

Abstract

Polygonum senegalense is a highland weed in eastern region of the African continent. Two forms are known to exist: forma senegalense and forma albomentosum. Both these forms are found in Kenya and are known to contain flavonoids. P. senegalense has two sets of flavonoids; a large number, wholly aglycones, is found on the leaf surface and on flowerheads while a lesser number is found in the inner tissues; existing mostly as glycosides. The surface flavonoid aglycones were first removed by washing leaves and flower heads of P. senegalense in acetone. The leaves were dried, macerated and cold extracted using methanol in water. The aqueous extract was washed in dichloromethane to remove any remaining aglycones before acid hydrolysis. The aqueous hydrolysate was partitioned into dichloromethane and then ethyl acetate.