Tabriz Valiasr International Hospital Publication International Journal of Drug Research in Clinics 2980-9835 4 1 2026 01 01 Evaluation of the Antioxidant Activity of Ethanol Extracts of Amaranthus spinosus and Hedyotis corymbosa Using the 2,2-Diphenyl-1-Picrylhydrazine Radical Scavenging Assay e9113 e9113 10.34172/ijdrc.9113 EN Tatang Irianti https://orcid.org/0000-0003-2771-6677 Sandricka Eleanor Dionisius Setyo Wibowo Putri Kusmawati Airin Khairunnisa Prima Rejeki Winda Rakhmadani Journal Article 10.34172/ijdrc.9113 2026 01 15 2026 04 15 Introduction: Free radicals are highly reactive molecules, so they can react with molecules around them. The use of antioxidants is one of the methods to reduce the effect of free radicals. Amaranthus spinosus and Hedyotis corymbosa (L.) are traditional medicinal plants with potential antioxidant properties. This study aimed to identify bioactive compounds and evaluate the antioxidant activity of ethanol extracts from these two medicinal plants using the DPPH method. Methods: Extraction was performed via maceration using 70% ethanol. In addition, total phenolic content (TPC) and total flavonoid content (TFC) were measured using the Folin-Ciocalteu and aluminum chloride methods, respectively. Finally, antioxidant activity was analyzed colorimetrically using a UV-Vis spectrophotometer. Results: The ethanol extract of A. spinosus demonstrated a TPC of 42.76 mg GAE/g and a TFC of 2.12 mg QE/g, with moderate antioxidant activity (the half-maximal inhibitory concentration [IC₅₀]=207.84 µg/mL). Moreover, the ethanol extract of H. corymbosa contained 36.11±0.48 mg GAE/g of phenolics and 11.26 mg QE/g of flavonoids, exhibiting moderate antioxidant activity with an IC₅₀ value of 137.86 µg/mL. Conclusion: These findings indicated that both plants hold promise as natural antioxidant sources for further development.