Antioxidant and xanthine oxidase inhibitory activity of euphorbia hirta leaves crude extract

Today, exposure to free radicals and gout cases have been a concern, showing several health effects from synthetic medications and clinical drugs for antioxidant effect and xanthine oxidase inhibition effect, respectively; all of which lead to the discovery of natural inhibitors from medicinal plants. In this study, a green solvent known as the deep eutectic solvent is synthesised to replace conventional solvents for the extraction of free radical inhibitors and xanthine oxidase inhibitors from a medicinal plant that has shown many health benefits and is widely used in traditional medicine, the Euphorbia hirta. The leaves extract from Euphorbia hirta showed the highest inhibition (87.95 ± 0.0061%) on free radical assays. The IC50 for free radical inhibition of the leaves extract is 10.56 ± 0.58 µg/mL. The IC50 value for xanthine oxidase inhibition of allopurinol was the lowest, which was at 6.94 ± 0.32 µg/mL; while the leaves extract of Euphorbia hirta exhibited value at 9.40 ± 0.13 µg/mL. The correlation value between the antioxidant effect and the xanthine oxidase inhibition of the leaves extract was 0.960, which indicated that there is a strong relationship between the two said parameters. From the Lineweaver-Burk plot and solver function analysis, the mode of enzyme inhibition was a non-competitive inhibition.