Interaction between natural antioxidants derived from cinnamon and cocoa in binary and complex mixtures

•Potential antioxidant activity of cinnamon and cocoa extract.•Various in vitro tests were applied to interaction determination.•Interaction determination of the combination of cinnamon and cocoa extracts.•Interaction determination of the paired major constituents in cinnamon and cocoa.

Cinnamon and cocoa are known to be valuable sources of bioactive phytochemicals, mainly the polyphenols. This paper investigates the potential antioxidant activity of cinnamon and cocoa extract and the interaction of their mixtures by various in vitro tests. Moreover, the combination effect of their constituents in a binary mixture was studied. Two representative active compounds of chocolate (epicatechin, catechin) were combined with seven of cinnamon (gallic acid, tannic acid, quercetin, sinapic acid, cinnamic acid, eugenol and cinnamaldehyde) in multilevel ratios. The results indicate that the addition of the cinnamon extract significantly increased the antioxidant activity of the cocoa extract. The interaction ranged from synergetic to antagonistic. The interaction was less synergetic when cinnamon extract was added in higher proportion. The interaction of their constituents substantially influenced the antioxidant activity of the mixture and was dependent on the ratio. The kinetics' study could elucidate how the polyphenols work in a mixture.