Phenolic extracts from leaves of bitter melon (Momordica charantia) with antioxidant properties.

Phenolic extraction from bitter melon (Momordica charantia) (BM) leaves was optimized to yield maximal phenolics with antioxidant potential using ethanol (EtOH) and water as solvents, and the phenolic extracts characterized for their individual phenolic acids. Assessment of total phenolics showed that 25% EtOH, an extraction at 40 °C for 30 min served as optimal extraction conditions from BM (30.7 mg CAE/g). BM-EtOH extract (1%) showed the highest free- radical scavenging abilities (89% at 180 min) versus BM-water extract (62.77% at 180 min). The antioxidant capacity of BM- EtOH extract (1%) was almost comparable to that of butylated hydroxytoluene (0.2%) at 180 min. The antioxidant stability of BM-EtOH and water extracts improved with incorporation of gums. Predominant phenolic compounds isolated from the extracts were o-coumaric, sinapic and ferulic acids. Bitter melon phenolic extracts contain potential free radical scavengers that could serve as natural and stable antioxidants along with gums in suitable food products.