A highly pure sub-fraction of shallot extract with potent in vitro anti-angiogenic activity

Our previous studies showed that various extracts of Persian shallot (Allium hirtifolium) have anti-angiogenic effects. This study has been undertaken to isolate and identify the major effective anti-angiogeneic sub-fraction of shallot. After preparation of the 50% hydroalcoholic extract of shallot bulbs, the extract was successively fractionated into n-hexane, ethyl acetate, n-butanol and aqueous fractions. Anti-angiogenesis activity of fractions was examined by in vitro angiogenesis assay. The ethyl acetate fraction which had the most anti-angiogenesis activity was further fractionated to four sub-fractions by thin layer chromatography (TLC), silica gel column chromatography and then analyzed by High Performance TLC (HPTLC) with ethyl acetate-methanol-water as the solvent system. Our results showed that one of the four sub-fractions, as the major band in HPTLC, had the most anti-angiogenic activity. Purification and characterization of the major anti-angiogenic compound/compounds of shallot''s extract may constitute one means by which diets rich in shallot confer protection against cancer and finally introduce new agents with pharmacological activities in shallot as a potential candidate in cancer therapy.