Phenolic compounds are highly correlated to the antioxidant capacity of genotypes of Oenocarpus distichus Mart. fruits

This research aimed to evaluate 32 genotypes of Oenocarpus distichus fruits regarding the contents of total phenolic compounds, flavonoids, flavanols, monomeric anthocyanins, antioxidant capacity (ABTS and DPPH assays), and the phenolic compound profiles of the five genotypes that presented the highest yields of bioactive compounds. The genotypes were harvested in three different locations in Para State, Northern Brazil, (Belem, Sao Joao do Araguaia and Mamba). Among the 32 genotypes, the highest bioactive compound contents and antioxidant capacity were found for three genotypes harvested in Belem (B-3, B-7 and B-8) and two harvested in Sao Joao do Araguaia (SJ-1 and SJ-4), and the total phenolic compounds varied from 131.97 to 363.01 mg gallic acid equivalent/100 g, total flavonoids from 24.23 to 38.19 mg quercetin equivalent/100 g, total flavanols from 72.29 to 259.18 mg catechin equivalent/100 g, and monomeric anthocyanins from 21.31 to 67.76 mg cyanidin 3-rutinoside/100 g. The main phenolic compounds tentatively identified in the five selected genotypes were cyanidin 3-0-rutinoside (48.47 to 196.51 mu g/g), which could be identified and quantified as the major phenolic compound in Oenocarpus distichus fruits, for the first time, followed by chlorogenic acid (0.71 to 64.56 mu/g) and rutin (13.98 to 56.76 mu/g).