CHROMATOGRAPHIC ISOLATION OF ALLIUM CEPA (SSP. RED ONION) AND ITS CYTOTOXIC ACTIVITY AGAINST HUMAN LIVER CARCINOMA CELL LINES (HEPG2)

Objective: The present study aimed to find out cytotoxic agent from Allium cepa L. (ssp. red onion) family Alliaceae as well as chromatographic isolation of its active constituents. Methods: The defatted methanol extract of Allium cepa (ssp. red onion) was fractionated with chloroform, ethyl acetate and n-butanol. Each of ethyl acetate and butanolic fraction was separately submitted to chromatographic isolation using different chromatographic techniques such as column chromatography (CC), thin layer chromatography (TLC) and paper chromatography (PC). The structures of the isolated compounds were elucidated through spectroscopic analysis. Results: Four compounds were isolated from ethyl acetate fraction and identified as kaempferol (1), quercetin (2) isorhamnetin (3) and isorhamentin-4`- O -β- D-glucopyranoside (4) whereas two compounds were isolated and identified from the butanolic fraction as α -D-glucopyranose (5), β-D-glucopyranosyl- α- D-glucopyranoside (6). The cytotoxic activity of defatted methanolic extract of A. cepa (ssp red onion), ethyl acetate and butanolic fractions against human liver carcinoma cell line (HepG2) was IC 50 = 10.9, 6.08 and 9.95 µg/ ml respectively. Also, compounds 4 isolated from ethyl acetate fraction and compound 6 isolated from butanolic fraction showed cytotoxic activity (IC 50 = 11.90 and 22.0 µg/ ml) respectively. Conclusion: It was appeared that the ethyl acetate fraction was the most active due to it contain high amount of phenolic compounds.