Bioactivity Guided Isolation of Quercetin as Anxiolytic Compound from Elaeocarpus ganitrus Beads

Context: In folk medicine the dried fruits of Elaeocarpus ganitrus Roxb. (Elaeocarpaceae), have been used in the treatment of melancholia, manic conditions and other psychological disorders. Objective: To isolate the anxiolytic constituent of E. ganitrus using bioactivity guided fractionation. Materials and methods: Crude extracts of E. ganitrus fruits were prepared using petroleum ether, chloroform and ethanol in a Soxhlet apparatus and finally the marc was boiled with water. Dried extracts were evaluated (50, 100, 200, 400 or 800 mg/kg, p.o) for antianxiety activity in mice using elevated plus maze apparatus (EPM). The most active ethanol extract (1000, 2000, 3000, 5000 mg/kg) was given to animals to observe acute toxicity, and observed for 14 days. Further the bioactive ethanol extract was subjected to column chromatography to isolate the bioactive constituent. The isolated constituent was further evaluated for antianxiety activity using EPM assay, light/dark chamber and double mirrored chamber model of anxiety. The structure of isolated compound was elucidated by IR, 1H NMR, and 13C NMR spectral data. Results: Results showed that no mortality was reported even after 14 days. This indicated that ethanol extract was safe up to a single dose of 5000 mg/kg p.o. Antianxiety activity guided fractionation of ethanol extract led to the isolation of 3,3',4',5,7-pentahydroxyflavone. The above isolated bioactive compound (25 mg/kg, p.o) exhibited significant anxiolytic activity in mice using EPM assay, light/dark chamber and double mirrored chamber model of anxiety. Conclusion: It is concluded that 3,3',4',5,7-pentahydroxyflavone is responsible for antianxiety activity of traditionally used E. ganitrus.