Phenolic Composition and Evaluation of Methanol and Aqueous Extracts of Bitter Gourd (Momordica charantia L) Leaves on Angiotensin-I-Converting Enzyme and Some Pro-oxidant-Induced Lipid Peroxidation In Vitro

This study sought to assess the effects of bitter gourd leaf extracts (methanol and aqueous) on enzyme linked with hypertension (angiotensin-I-converting enzyme and some pro-oxidants (iron sulfate, sodium nitroprusside, and cisplatin]–induced lipid peroxidation in rat kidney homogenates. Chromatographic analysis of the extract was done using high-performance liquid chromatography–diode array detection. The results revealed that methanol extract (IC50 = 109.63 µg/mL) had significantly ( P < .05) higher angiotensin-I converting enzyme inhibitory activity than aqueous extract (IC50 = 182.95 µg/mL). Similarly, methanol extract had significantly ( P < .05) higher inhibitory effect on Fe2+- and cisplatin-induced lipid peroxidation than aqueous extract. However, there was no significant ( P > .05) difference in the inhibition of sodium nitroprusside–induced lipid peroxidation of both extracts. High-performance liquid chromatography–diode array detection analysis revealed the presence of quercetin, caffeic, gallic, and chlorogenic acids in the leaf. Thus, inhibition of angiotensin-I converting enzyme activity and the antioxidant properties of the extracts could be linked to the presence of phenolic phytochemicals.