Isolation and characterization of some flavonoids from the leaf of Tapinanthus globiferus growing on Vitex doniana

Tapinanthus globiferus (A. Rich) Tiegh (Loranthacae) is a semi-parasitic plant growing on several plant species such as Vitex doniana. it is used in ethno-medicine for the treatment of fungal infection, itching, hypertension, ulcers, epilepsy, diabetes and cancer. The aim of this study was to isolate bioactive compound(s) from the leaf of T. globiferus. The powdered plant material was extracted with 90% methanol using maceration method and the resulting crude methanol leaf extract was partitioned into n-hexane, chloroform, ethylacetate and n-butanol fractions. The ethylacetate fraction was chromatographed on a silica gel and sephadex LH-20 column which led to the isolation of two flavonoids, and the identity of the compounds was determined on the basis of chemical test and NMR analysis. Based on the 1D and 2D NMR data, the compounds were 2-(3’4’-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromane-4-one (quercetin) and 2-(2,4-dihydroxyphenyl)-5,7-dihydroxy-3-(3-methylhexyl)-4H-chromen-4-one. This is the first report of isolation of these compounds from T. globiferus growing on Vitex doniana.