Synergistic antioxidant interactions between green tea and Ocimum gratissimum

ABSTRACT

Objective: To evaluate the antioxidant interactions between aqueous infusions of green tea and Ocimum gratissimum at different ratios. Methods: Antioxidant activities of aqueous infusion of green tea and Ocimum gratissimum (leaves) alone or in combination at various proportions (31, 21, 11, 12, 13) were determined by DPPH, ABTS, NO and ex-vivo assays including lipid peroxidation and haemolysis. Total phenolic content and flavonoid content was calculated by Folin-Ciocalteu reagent and aluminum chloride colorimetry method, respectively. A correlation study was also conducted between the antioxidant activity and total phenolic/flavonoid content of various infusions. The interactions were analyzed by combination index applying CompuSyn software. Results: Green tea exhibited high radical scavenging ability as compared to Ocimum gratissimum infusion. Combination of green tea and Ocimum gratissimum exhibited moderate antagonism to strong synergistic interaction at various ratios. A strong correlation was found between total phenolic content/total flavonoid content and antioxidant activities of individual infusions (green tea and Ocimum gratissimum). For binary mixture at different ratios, a weak to strong correlation was observed between total phenolic content and antioxidant activity and almost no correlation between total flavonoid content and antioxidant potential. Conclusions: Overall, green tea and Ocimum gratissimum combination (11) displayed the highest antioxidant potential and maximum synergism.