Studies on the antioxygenic activity of bitter gourd (Momordica charantia) and its fractions using various in vitro models

BACKGROUND: A study was undertaken to evaluate the antioxygenic activity of bitter gourd pulp and seed powders as well as their various solvent extracts using different methods and to minimise the oxidative deterioration of lipids by natural antioxidants. RESULTS: Bitter gourd pulp and seed powders at 20 g kg(-1) and their ethanol/water extracts exhibited stronger antioxygenic activity than other solvent extracts. Bitter gourd pulp and its extracts showed slightly higher antioxygenic activity than bitter gourd seed and its extracts. This may be attributed to the presence of higher amounts of phenolics and flavonoids, which have been reported as potential antioxidants. The seed portion of bitter gourd contained higher levels of total protein (188.3 g kg(-1)), total fat (238.9 g kg(-1)) and crude fibre (350.2 g kg(-1)) than the pulp portion. Fatty acid analysis of bitter gourd seed oil indicated the presence of a-eleostearic acid, an isomer of conjugated linolenic acid, as a major fatty acid, but this acid was absent in the pulp. CONCLUSION: The results of this study confirmed the presence of antioxygenic compounds in both bitter gourd pulp and seed. In particular, their ethanol/water extracts showed great potential as natural antioxidants to inhibit lipid peroxidation in foods. (C) 2010 Society of Chemical Industry