Antioxidant capacity and phenolics of Pouteria macrophylla, an under-utilized fruit from Brazilian Amazon

The potential of fruits occurring in the Amazon with regard to their antioxidant capacity is being addressed increasingly during the last years. In this paper, the antioxidant capacity of fruits from Pouteria macrophylla (cutite) and the compounds which are responsible for that functional property were studied. Diphenyl-picrylhydrazyl (DPPH) and total oxidant scavenging capacity (TOSC) assays were used for the evaluation of antioxidant capacity of fruit aqueous extracts. TOSC assay showed inhibitory effects against peroxyl (TOSC50% = 560 mg/L) and peroxynitrite (TOSC50% = 830 mg/L), two important reactive oxygen species, while DPPH showed that cutite (EC50 = 300 ± 3.9 g/g DPPH) has significant antioxidant capacity, greater than many other known Amazon fruits. It was also seen that the cutite fruits are a good alimentary source of polyphenols (867 ± 8 mg GAE/100 g), analyzed by Folin-Ciocalteu assay. Using HPLC-DAD-ESI-MSn and HPLC-DAD, gallic acid (4.72 mg/g fresh fruit pulp) and digalloyl glucose were found as the main phenolic compounds in the cutite fruits. TOSC assays with HPLC fractions of fruit aqueous extracts show that both compounds are predominantly responsible for the antioxidant capacity observed in the cutite.