Antioxidant activity of combined aqueous extracts of Curcuma longa Linn. rhizome and Tamarindus indica Linn. fruit pulp

Turmeric-tamarind herbal drink (jamu kunyit asam) is a well-known traditional herbal drink in Indonesia. The two main ingredients of the drink are aqueous extracts of turmeric rhizome and tamarind fruit pulp. This study aimed to investigate the antioxidant activities effect of combined aqueous extracts of turmeric rhizome and tamarind fruit pulp because it has not been investigated. The aqueous extracts were mixed in various combinations. The mixtures' pH, total phenolics content, and antioxidant activity (DPPH) were measured. The mixture's pH was determined mainly by the tamarind extract dose. Nevertheless, the ratio of the extracts did not influence the total phenolic compounds. At the lower dose of tamarind extract, the antioxidative interaction of both sections was synergistic, but at the higher amount, it was additive. All mixtures' antioxidant potential (DPPH-IC50) was lower than BHT (the standard control). The antioxidative interaction is synergistic if the extracts ratio is unequal.