ISOLATION AND CHARACTERIZATION OF QUERCETIN AND KAEMPFEROL FROM Ginkgo biloba LEAVES GROWN IN EGYPT

Abstract

In the present study, Ginkgo biloba leaves were extracted with methanol 80% and fractionated by sequential extraction with petroleum ether (Fr-l), ethyl ether (Fr-II) and ethyl acetate (Fr-III) separately. Fraction III was co-chromatographed after hydrolyzed with 7% sulphuric acid with 3 solvent systems. Paper chromatography on Whatman cellulose chromatography papers 3 CHR with benzene, acetic acid and water (125: 72: 3) as mobile phase enabled good separation of quercetin at 0.6 RF and kaempferol at 0.78 RF. In the present study, quercetin and kaempferol were isolated from Ginkgo biloba leaves grown in Egypt and characterized by various spectral studies. The ethanolic extract of Ginkgo biloba leaves was subjected to high-performance liquid chromatography analysis for the identification of major phenolics and flavonoids. Eleven components were detected. Most flavonoids in Ginkgo biloba leaves are the derivatives of quercetin, and kaempferol. The results were obtained from UV and FTIR indicated for the molecular structure of quercetin and kaempferol. The mass spectrum of kaempferol and quercetin was observed at m/z 286.8 and 302.9, respectively. The results of the present study established the presence of biologically active phytochemicals in the Ginkgo biloba leaves. The results also suggested that the Ginkgo biloba leaves extract contain significant amounts of quercetin and kaempferol. Thus, it may be concluded that the Ginkgo biloba leaves have great potential for producing healthy and highly nutritive products.