Costus pictus D. Don. ex. Lindl., a member of the Costaceae family, and Dodonaea viscosa (L.) Jacq., belongs to the family, Sapindaceae which is primarily found in tropical regions. Their medicinal properties are attributed to their chemical compounds, including alkaloids, flavonoids, phenols, tannins, and antioxidants, which are essential for health benefits. This study sought to assess the phytochemical and antioxidant activity of C. pictus and D. viscosa leaves that were extracted using various solvents, and the interrelation between the phytochemical and its antioxidant potential was measured. The antioxidant capacity was determined using approaches such as radical scavenging, metal chelating, and reducing power assays, since a comparative analysis employing various antioxidant evaluation methods suggests that not all adopted methods are substantially linked. Out of the seven approaches that were examined, 2,2-diphenyl-1-picrylhydrazyl (DPPH) was found to have the highest sensitivity in this study. Methanol extracts of C. pictus and D. viscosa showed the highest antioxidant activity with lower IC50 concentrations of 50.79 and 84.59 mu g/ml, respectively. Moreover, similar settings were observed in other approaches that exhibit the potential of antioxidant activity. The higher association of antioxidant activity with phytochemicals such as phenols (r = - 0.46, - 0.45), alkaloids (r = - 0.79, - 0.58), tannins (r = - 4.22, - 0.55), and less with flavonoids (r = 0.25, - 0.01), respectively, in C. pictus and D. viscosa extracts was observed. However, the soxhlet extraction method produces a higher extractive yield than other methods. The results of this study suggest that C. pictus and D. viscosa could be considered capable sources of natural antioxidants and support the use of these medicinal plants to treat a variety of diseases.
