Effect of pectin on the interactions among phenolic compounds determined by antioxidant capacity

Abstract

Antioxidant capacity of the phenolic compounds depends on their chemical structures and interactions between them. Twenty binary combinations between four phenolic acids (gallic acid, coumaric acid, chlorogenic acid, caffeic acid) and four flavonoids (catechin, quercetin, epicatechin, and rutin) were analyzed to evaluate the effect of their combinations by DPPH and FRAP methods. Isobolograph analysis and combination index (CI) were used for DPPH, and the percentage of differentiation for FRAP method to evaluate the effect of the PC binary combinations (synergism, additive or antagonism). Chlorogenic acid presented the highest inhibition of DPPH, while coumaric acid did not present any DPPH inhibition. Gallic acid and catechin showed better ferric reducing capacit. The antioxidant capacity increased when pectin is mixed with individual PC. The isobologram method shows that the PC binary combinations presented additive or antagonistic effects in the DPPH method. A synergistic effect on DPPH radical inhibition and FRAP method was presented in most of the combination of phenolic compounds with pectin. The antioxidant capacity depends on the type and the location of hydroxyl, and the type of phenolic compounds.