Comparative Study of Antioxidant Properties and Total Phenolic Content of Selective Herbs

Abstract This comparative study investigates the antioxidant properties and total phenolic content (TPC) of five medicinally important herbs: Tridax procumbens , Catharanthus roseus , Datura inoxa , Asian pigeonwings ( Clitoriaternatea ), and Lantana camara . These herbs are extensively utilized in traditional medicine systems across Asia for their diverse therapeutic applications and potential health benefits. The antioxidant capacity was comprehensively evaluated using multiple standardized assays, including DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, FRAP (Ferric Reducing Antioxidant Power) assay, nitric oxide radical scavenging assay, and ferric thiocyanate (FTC) method. Total phenolic content was quantified using the Folin-Ciocalteu method, with results expressed as gallic acid equivalents (GAE). Results revealed significant inter-species variations in both antioxidant activities and phenolic content. Datura inoxa demonstrated the highest total phenolic content (133.77 mg/mL) and exhibited superior antioxidant activity across multiple assays, including DPPH scavenging (86.54%), nitric oxide scavenging (98.93%), and FTC inhibition (95.20%). Tridax procumbens showed consistently high antioxidant potential with 84.05% DPPH scavenging activity, while Catharanthus roseus , Asian pigeonwings, and Lantana camara displayed moderate to good antioxidant capacities. A strong positive correlation was observed between total phenolic content and antioxidant capacity, confirming the pivotal role of phenolic compounds in the antioxidant mechanisms of these herbs. This study provides valuable insights into the comparative antioxidant potential of these medicinal plants, supporting their traditional uses and highlighting their promise as natural sources of antioxidants for pharmaceutical and nutraceutical applications. Further investigations into the specific bioactive compounds and their mechanisms of action are warranted to fully exploit their therapeutic potential.