Radical scavenging, antioxidant and metal chelating activities of Annona cherimola Mill. (cherimoya) peel and pulp in relation to their total phenolic and total flavonoid contents

This study aimed to evaluate the total phenolic and flavonoid content, radical scavenging activity (by DPPH and ABTS tests) and antioxidant capacity (by beta-carotene bleaching test) of Annona cherimola (cherimoya) fruits cultivated in Italy for human consumption. The metal chelating activity and ferric reducing power were also determined. A. cherimola peel and pulp were characterized by a total phenolic content of 14.6 and 12.6 mg chlorogenic acid equivalents/100 g fresh weight, respectively. A similar trend was observed with flavonoid content. Both extracts exhibited high antioxidant activity through different mechanisms of action. In particular, peel extract demonstrated the strongest free radical scavenging activity with an IC50 value of 57.7 mu g/mL. The same extract was more effective in preventing beta-carotene oxidation (IC50 value of 63.5 mu g/mL after 60 min) and showed higher chelating ability (IC50 value of 79.6 mu g/mL) than pulp extract. This work demonstrated the high quality of cherimoya fruits cultivated in Italy, and recommends the peel of this fruit product that may be of interest from a functional point of view as a major source of natural antioxidants. (C) 2011 Elsevier Inc. All rights reserved.