Comparative Analysis of Antioxidant Properties in Green and Reddish-Brown Leaves of Terminalia catappa Using DPPH and Nitric Oxide Assays

This study evaluated and compared the antioxidant properties of the reddish-brown and green leaves of Terminalia catappa. The reddish-brown and green leaves of T. catappa were collected from Agwan-kadara Television, Chikun LGA of Kaduna State in Nigeria. These were collected and processed separately; 270g of each of the ground samples was used to prepare the methanol and aqueous extracts, respectively. Phytochemical analysis was conducted to determine the quantities of polyphenols, flavonoids, tannins, saponins, and alkaloids in the leaf samples. The antioxidative potential of the plant was determined by analyzing the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and nitric oxide reducing activity. Methanol and aqueous extracts of the reddish-brown leaves of T. catappa yielded 31.6 g and 52.2 g of extract, respectively. The phytochemical constituents found in the methanol and aqueous extracts of reddish-brown leaves of Terminalia catappa showed a significant difference in flavonoids and polyphenols, but there was no significant difference in alkaloids (13.9±0.02mg/g), tannins (90.4±0.07 mg/g), and saponins (152.2±0.85 mg/g). The methanol and aqueous extracts of the green leaves of Terminalia catappa showed no significant difference in flavonoids (96.9±7.02mg/g), polyphenols (110.0±14.1mg/g), and alkaloids, but there was a significant difference in tannins (123.2±0.38mg/g) and saponins (143.6±1.03mg/g). The high presence of phytochemicals and antioxidant potential of Terminalia catappa justifies its use in traditional medicine because of its beneficial medicinal activity. This study also suggests both the reddish-brown and green leaves of T. catappa as effective antioxidants.