Background: The study investigates the antioxidant properties of Catharanthus roseus, focusing on identifying its antioxidant compounds and chemical constituents. We compare antioxidant activities across its root, stem, flower, and leaf and examine the inhibition of reactive oxygen species (ROS)–generating enzymes by the plant’s phytocompounds.Methods: We conducted a comprehensive analysis that included proximate analysis, mineral content assessment, and in vitro antioxidant characterization of various plant parts—root, stem, flower, and leaf. The levels of bioactive phytochemicals in both ethanol and mixed‐solvent extracts of Catharanthus roseus were quantified using high‐performance liquid chromatography with a diode array detector (HPLC‐DAD). Additionally, we performed molecular docking studies to explore the interactions of quantified phytocompounds.Results: HPLC‐DAD analysis quantified catechin hydrate, catechol, (−) epicatechin, rutin hydrate, trans‐cinnamic acid, quercetin, vanillic acid, kaempferol, and trans‐ferulic acid in Catharanthus roseus. Despite the ethanol extract having higher total antioxidant properties and flavonoid content, the mixed‐solvent extract exhibited higher EC50 for reducing power and lower IC50 for ABTS, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), and metal chelating activities. Molecular docking studies indicated that compounds such as catechin, rutin, epicatechin, quercetin, and kaempferol significantly inhibit the ROS‐generating enzyme microsomal prostaglandin E synthase 1 (mPGES‐1).Conclusions: The mixed‐solvent extract had higher levels of catechin hydrate, rutin hydrate, trans‐ferulic acid, and vanillic acid, whereas the ethanol extract contained more (−) epicatechin, catechol, kaempferol, quercetin, and trans‐cinnamic acid. While the extracts displayed antioxidant activity, the phytoconstituents also inhibited ROS‐generating mPGES‐1. These results identify key compounds with potential for developing new chemotherapeutic agents against ROS.
