Euphorbia hirta Methanolic Extract Displays Potential Antioxidant Activity for the Development of Local Natural Products

Background: The level of free radicals, which counteract the capability of the antioxidant system in plant products, is often measured in advance for further promising antidisease effect. Objective: In this study, we sought to evaluate the antioxidant activity of local medicinal plants (Angelica keiskei, Annona muricata, Chromolaena odorata, Clinacanthus nutans, Euphorbia hirta, and Leea indica) for their potential of use as distinctive local natural nutraceutical products. Materials and Methods: To recover active compounds, including yield and composition of the plants, the solvent extraction method, the Folin–Ciocalteu method, the aluminum chloride approach, and the 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) radical scavenging assay were first performed to evaluate the antioxidant level and capacity of the plant extracts. Results: The aqueous extracts presented the highest yield for all plants, with the highest yield observed in C. nutans. However, the highest total phenolic and flavonoid contents were observed in the methanolic extract of E. hirta rather than in the aqueous extract. The methanolic extract of E. hirta also exhibited the most promising antioxidant activity, with the 50% inhibition concentration (IC50) value of DPPH inhibition at 0.013 mg/mL. Conclusion: High total phenolic and flavonoid contents, as well as low IC50 value, suggested that E. hirta methanolic extract is a potential antioxidant agent for the development of local natural products for disease treatment.