Phenolic compounds in different parts of young Annona muricata cultivated in Korea and their antioxidant activity

The antioxidant activities of 80% methanol and distilled water extracts of different parts (roots, twigs, and leaves) of young Annona muricata were estimated based on their total phenol and flavonoid content as well as in vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, nitrite scavenging activity, Fe 2+ -chelating activity, ferric reducing antioxidant power (FRAP), and phenolic compound assays. The 80% methanol extracts showed a higher antioxidant effect than that of the water extracts. The 80% methanol root and leaf extracts showed higher total phenol (839.69 mg CAE/g) and flavonoid (168.52 mg RE/g) contents than those shown by the other extracts. In addition, the 80% methanol root extracts showed high DPPH (EC 50 = 0.18 mg/mL) and ABTS (EC 50 = 0.55 mg/mL) radical as well as nitrite (EC 50 = 0.21 mg/mL) scavenging activities. The metal-chelating effect of the 80% methanol twig extract was the highest, but there were no significant differences among the 80% methanol extracts of the different parts. FRAP values of all extracts increased in a concentration-dependent manner, except for those of the distilled water leaf extract, while the 80% methanol root extracts showed the highest value. In addition, there was a strong positive correlation between the antioxidant activity and total phenol content ( P < 0.01). A. muricata extracts were rich in various phytochemicals including rutin, epicatechin, ferulic acid, and p -coumaric acid. These findings indicate that A. muricata is a potentially useful source of substances with antioxidant effects.