eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2025-06-25 22 2 557 568 10.13005/bbra/3383 55400 article Bijayananda Sahoo 1 Shubham Pradhan 1 Satyabrata Dash 1 Biswajit Rath 1 Department of Biotechnology, Maharaja Sriram Chandra Bhanja Deo University, Baripada, Odisha, India The present investigation was carried out to understand the phytochemical composition, catalase activity, and H₂O₂ radical scavenging efficiency in Parmotrema tinctorum across zones of Similipal Biosphere Reserve (transition, buffer, and core). Phytochemicals include phenolic, flavonoid, tannin, and terpenoid contents varied across zones, with the transition zone showing the highest phenolic content (319.95 ± 9.2 µg/g GAE). Catalase activity was highest in the core zone (10.44 ± 0.41 U/g), decreasing progressively towards the buffer zone. H₂O₂ radical scavenging assays established an increase in extraction efficiency with higher methanol concentrations, with the transition zone displaying the highest efficiency, peaking at 76.84 ± 1.48% at 500 µL. The transition zone also showed the significant IC₅₀ (245.52 µg/mL), indicating superior antioxidant potential compared to the buffer and core zones. These findings suggest that environmental factors influence secondary metabolite distribution and catalase activity, with distinct metabolic adaptations in each zone. The concentration-dependent scavenging activity in the transition zone highlights it as the most active region, contributing valuable insights into the ecological and adaptive physiology of P. tinctorum. These differences suggest adaptive metabolic responses across zones, influenced by environmental factors, enhancing the lichen resilience and ecological function. https://www.biotech-asia.org/vol22no2/a-comparative-study-of-antioxidative-properties-of-the-lichen-parmotrema-tinctorum-distributed-in-different-regions-of-similipal-biosphere-reserve-odisha-india/ Catalase activity; Ecological zone; FTIR; GCMS; Lichen metabolites; Variation