Isolation, Characterization and Biological Activity of Flavonoids from (Vitex doniana)

Abstract

Vitex doniana (subfamily Viticoideae) was chosen for this study because of its use in Sudanese folk medicine for the treatment of common disease as rheumatism, hypertension, cancer, anemia, stomach disorders, rickets, leprosy, sterility, diarrhea, dysentery, fevers, debility, pain-killers and kidney diseases. Vitex doniana leaves extract with 70% methanol was prepared at room temperature. Preliminary phytochemical screening, of air-dried powdered leaves, indicated high amounts of saponins and flavonoids, moderate amounts of carbohydrates or carbohydrates and glycosides, sterols or sterols and triterpenes, coumarins and alkaloids, while crystalline sublimate, anthraquinones and volatile matter were absent. Study of the aqueous methanol extract of the plant using chromatographic separation on polyamide, sephadex column and paper chromatography method, resulted in isolation of five compounds as flavone (I, II, III, IV, V) (three as glycosidic flavonoids and two as aglycones). The structures of the isolated phytochemicals were elucidated using UV, 1H-NMR, 13C-NMR and MS. All compounds were isolated for the first time from the leaves extract. Methanol extract of Vitex doniana exhibited high antibacterial activity against gram negative bacteria: Pseudomonas aeruginosa and moderated activity against gram negative bacteria: Salmonella typhimurium. Minor activity observed for gram positive bacteria: Bacillus aureus. In addition, the extract gave significant antifungal activity against Candida albicans reaching an inhibition zone: 15mm showed high antifungal activity. Percentage inhibition absorbance of (91.0 %) was observed for DPPH, indicating high antioxidant activity of the leaf extract.