Effect of Heat Processing Treatments and Extraction Solvents on the Phenolic Content and Antioxidant Activity of Momordica charantia Fruit

The effect of different cooking treatments and extracting solvents on the antioxidant activity of M. charantia was assessed by measuring total phenol content (TPC), total flavonoids, tannin content and carotenoid content and the antioxidant activity using different assays. A densitometric HPTLC analysis was performed for the analysis of phenolic acids and flavonoids. In general, the recovery of TPC and antioxidant activity was highest in methanolic extract. The most of cooking treatments exerted the decreasing effect on antioxidant activity. Correlation studies indicated that the phenols were mainly responsible for ferric reducing power (r=0.872, P<0.01). However, the flavonoids were responsible for radical scavenging activity (r=0.857, P<0.01). HPTLC analysis of the methanolic extracts revealed the prominent presence of caffeic acid, vanillic acid, quercetin, catechin, etc., in the native form and destruction, transformation and formation of new phenolics was observed after the cooking treatments.