Antioxidant capacity interactions and a chemical/structural model of phenolic compounds found in strawberries.

The interactive antioxidant capacity of phenolic compounds from specific foods has not been well explored. The antioxidant capacity of a whole fruit exceeds the sum of the antioxidant capacities of individual antioxidants within that fruit, suggesting synergism among compounds. The interactions of seven phenolic compounds (p-coumaric acid, cyanidin, catechin, quercetin-3-glucoside, kaempferol, pelargonidin and ellagic acid) at relative concentrations found in strawberries were tested using the oxygen radical absorbance capacity assay. Statistically significant synergism was found for three combinations of two phenolic compounds, and among five combinations of three phenolic compounds. Statistically significant antagonism was observed among two combinations of two phenolic compounds and among one combination of three compounds. A chemical/structural model that best explained the results included reduction potentials, relative concentration, and the presence or absence of catechol (o-dihydroxy benzene) groups. This work demonstrates unique interactions that occur in a complex environment within the framework of strawberries. The synergism discovered at food-based antioxidant ratios could be applied to food preservation.