Isolation and Characterization of Chemical Constituents from Roots of Cyphostemma adenocaule and Investigation of its Antibacterial and Antioxidant Activities

Abstract

The Vitaceae, or grape family, contains around 900 species and 15 genera, including cyphostemma, mainly having the liana growth form. C. adenocaule is one of over 6500 flowering plants and ferns found in Ethiopia. Its different parts are culturally used for different purposes in East African countries including Ethiopia like as a source of food, medicine, insecticide and fibers. Locally people use this plant for treating rabies. But, no detailed scientific investigation is available on the chemical composition of this plant. So, this research was aimed to isolate and characterize the chemical constituents from roots of the plant and to investigate its antibacterial and antioxidant activities. To achieve this objective, the root of the plant was extracted by methanol and successively suspended by hexane, chloroform and ethyl acetate. Phytochemical screenig was carried out on methanol extract. The result indicated the presence of alkaloid, saponnin, condensed tannin and flavanoid. The hexane, chloroform and ethyl acetate soluble portion was mixed and subjected to column chromatography based on their TLC profile and two compounds were selected for characterization namely F(13-18)2 and F(13-18)5. The condensed tannin, F(S), was purified from ethyl acetate insoluble portion by using sephadex LH-20 and the structures of all obtained compounds were elucidated by using UV, IR and NMR. The effect of F(S) on activities of four selected bacteria using different concentrations, 0.01, 0.1, 1, 10 mg\ml, was tested. The highest inhibition zone for Escherichia coli (8 mm) and Staphylococcus aurous (11 mm) were seen with 10 mg/ml. But, the highest inhibition zone for the other two bacteria, Salmonella thyphomurium (25 mm) and Streptococcus buvis (14 mm), were observed with 0.1 mg/ml. The antioxidant activity of the F(S) was evaluated by DPPH free radical using concentrations, 62.5, 125, 250, and 500µg/ml. Their % DPPH inhibition was 96, 95, 93, and 88 %, respectively. The purified condensed tannin was observed as it shwed good antibacterial activities and strong antioxidant activities when compared with condensed tannins reported from other plants. But, the concentration of condensed tannin in different maturity of the plant should be studied in detail.