Antioxidant properties of solvent extracts from Terminalia catappa leaves

Solvent extracts were prepared from green, yellow fallen and red fallen leaves of Terminalia catappa L. and their antioxidant activities were evaluated. Other antioxidant properties of methanolic extracts, including reducing power, scavenging and chelating effects, were also determined. The yields were consistently in the order of yellow fallen (6.34-10.50%)>red fallen (5.12-9.98%)>green leaf extracts (2.36-6.08%) for four solvents used. Higher yields were obtained from extraction with ethyl acetate or methanol than with dichloromethane or pentane. For three different leaves, the antioxidant activities were in the order methanol>ethyl acetate>dichloromethane>pentane extracts and all showed a parabolic-like curve with the maximum at 0.1-0.5 mg ml(-1) of solvent extract. Reducing powers of three methanolic extracts and their scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radicals were excellent at 0.5 and 0.1 mg ml(-1), respectively. At 30 mg ml(-1), chelating effects of methanolic extracts from green, yellow fallen and red fallen leaves on ferrous ions were 77.3, 48.6 and 48.3%, respectively. (C) 2002 Elsevier Science Ltd. All rights reserved.