Antioxidant potentials and degrees of polymerization of six wild fruits

Abstract

Aqueous methanolic extracts of six wild fruits, Ximenia caffra (sour plum), Sclerocarya birrea (marula), Parinari curatellifolia (mobola plum), Vitex payos (chocolate berry),Bridelia molis (velvet sweet-berry) and Berchemia zeyheri (red ivory) were assayed for radical scavenging effect on DPPH radical, reducing power, superoxide anion radical scavenging effect and the inhibition of phospholipids peroxidation using colorimetric method. The peels and pulps of sour plum exhibited high activity compared to the peels and pulps of the other fruits. Sour plum showed high reducing capacities both in the peel and pulp compared to all the other fruits. At high concentrations of extract over 75% superoxide anion scavenging effect was observed for velvet sweet-berry whilst at concentrations of 40 and 60 mg sample equivalent/μl red ivory fruits showed a high anion scavenging capacity. Velvet sweet-berry, sour plum peel and pulp and chocolate berry peel showed high capacities to inhibit lipid peroxidation at high concentrations. The degrees of polymerization varied between 7 to 16 monomer units of catechin per polymer of phenolic compounds in the different portions of the six fruits. Key words: Phenolic acids, antioxidant, wild fruits, peroxidation and polymerisation.