Objectives: Male infertility has been associated with oxidative stress-induced and/or microbial induced in some men. The use of medicinal plants to overcome oxidative stress-induced infertility cannot be over emphasized. Hence, the aim of this research was to isolate the antilipid peroxidation (an index of usage for treating oxidative stress-induced male infertility) bioactive principle from Momordica charantia using bioactivity-guided isolation.
Materials and methods: n-Hexane fraction from the crude ethanol extract obtained by Soxhlet extraction of aerial parts (without fruit) of bitter melon, M. charantia, was assessed for in vitro lipid peroxidation, followed by bioactivity-guided isolation of bioactive principles using in vitro lipid peroxidation as an index of aphrodisiac and male fertility enhancer.
Results: Fractionation of the active n-hexane fraction using vacuum liquid chromatography (VLC) gave five pooled fractions on the basis of their thin layer chromatography (TLC) characteristics (n-hexane: EtOAc, 2:3, sulphuric acid spray). In vitro activity of the most active VLC fraction C was less than that of the positive control, vitamin E. Further fractionation of VLC-C by open column chromatography on silica gel led to the isolation of a compound which was purified by preparative-TLC. The purified compound, 10 mg/mL (Rf 0.54, TLC silica gel, n-hexane: ethyl acetate; 2:3) was equipotent with vitamin E (25 mg/mL) in reducing peroxidation of polyunsaturated fatty acids in vitro. Structural elucidation by NMR (1H, 13C) and mean mass spectroscopy confirmed the identity of the new bioactive compound as 13, 14-epoxyoleanan-3-ol-acetate.
Conclusion: This study scientifically validates the traditional claim of M. charantia as an aphrodisiac or male fertility enhancer and suggests that 13, 14-epoxyoleanan-3-ol-acetate might be responsible for the observed activity.
Keywords: 13, 14-epoxyoleanan-3-ol-acetate; Momordica charantia; VLC; in vitro lipid peroxidation assay; n-hexane fraction; vitamin E.