The study investigates the phytochemical composition, free radical scavenging activities and antioxidative potential of various extracts of M. macrophylla. Phytochemicals such as alkaloids, cardiac glycosides, saponins, steroids, tannins, and terpenoids were found to be present in various extracts of M. macrophylla. Aqueous extract of M. macrophylla have the highest total phenolic (387.61 ± 14.10 mg GAE/g) and flavonoid (5761.65 ± 38.5 mg quercetin equivalent/g) contents. The antioxidative potential of M. macrophylla extracts was measured by their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anions (O2-) and 2, 2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) in a cell free system. The aqueous extract of M. macrophylla possessed the highest scavenging activities for DPPH, O2- and ABTS with IC50 of 25.92 ± 0.33 μg/ml, 4.12 ± 0.94 μg/ml and 17.20 ± 0.50 μg/ml, respectively. Furthermore, the scavenging activities of the aqueous extract of M. macrophylla against ABTS and O2- were found to be more effective than ascorbic acid which was used as standard. The total reducing power of M. macrophylla extracts was also determined by measuring the transformation of Fe3+ into Fe2+ and the methanolic extract was found to exhibit the highest reducing power. The aqueous extract of M. macrophylla showed the highest inhibitory activities against mice erythrocyte hemolysis and lipid peroxidation in liver homogenate with an inhibition rate of 80.53 % and 65.33 % respectively.
Key words: Mussaenda macrophylla, ABTS, antioxidants, anti-haemolytic, lipid peroxidation.
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