eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2026-09-14 23 3 59786 article Antu Mariya Jose 2 Jinu John 3 Rogimon Plammoottil Thomas 1 Department of Botany, CMS College Kottayam (Autonomous), Kerala, India Department of Botany, B. C. M. College Kottayam (Autonomous), Kerala, India Department of Biotechnology, CMS College Kottayam (Autonomous), Kerala, India Comparative phytochemical screening and antioxidant evaluation were performed on leaf extracts of Rotheca serrata (L.) Steane & Mabb. and Rotheca microphylla (Blume) Callm. & Phillipson (Lamiaceae). Standard qualitative assays indicated the presence of alkaloids, tannins, flavonoids, glycosides, sugars, anthraquinones, steroids, terpenoids and amino acids in both species. Antioxidant activity was assessed using DPPH radical scavenging, nitric oxide scavenging, phosphomolybdenum reducing power and ferric-reducing antioxidant power (FRAP) assays. In the DPPH assay, IC₅₀ values were 66.1 µg·mL^-1 for R. serrata and 74.6 µg·mL^-1 for R. microphylla; in the nitric oxide assay, IC₅₀ values were 41.7 µg·mL⁻¹ and 57.6 µg·mL⁻¹, respectively, demonstrating greater radical-scavenging potency for R. serrata. In reducing-power assays, R. microphylla exhibited higher phosphomolybdenum reducing capacity, whereas R. serrata showed stronger FRAP activity. Total phenolic content measured by the Folin–Ciocalteu method was higher in R. serrata (746.26 ± 8.42 µg GAE·g⁻¹ extract) than in R. microphylla (661.58 ± 13.08 µg GAE·g⁻¹ extract), which correlates with the marginally greater overall antioxidant activity observed for R. serrata. These findings identify both Rotheca species as promising sources of natural antioxidants. The study's novelty lies in providing the first comparative antioxidant and phytochemical profiling of R. serrata and R. microphylla, establishing a quantitative link between phenolic content and antioxidant efficacy and generating baseline data that support isolation and structural elucidation of bioactive constituents and subsequent in vivo and mechanistic investigations. The results have potential implications for the development of plant-derived antioxidant agents and for ethnopharmacological validation of Rotheca species. https://www.biotech-asia.org/vol23no3/comparative-phytochemical-profiling-and-antioxidant-activity-of-selected-plants-of-the-genus-rotheca-raf-lamiaceae/ Antioxidants; Clerodendrum serratum; Phytochemistry; Rotheca microphylla; Rotheca serrata; Total phenolic content