Abstract: Pterocarpus marsupium Roxb. is an important medicinal tree of the Fabaceae family that has been traditionally used in Indian systems of medicine and is recognized for its diverse pharmacological properties. The plant contains a wide range of biologically active phytoconstituents, particularly phenolic compounds, flavonoids, stilbenes and other secondary metabolites that may contribute to its antioxidant potential. The present study was undertaken to determine the free radical scavenging activity of different plant parts and in vitro-derived tissues of P. marsupium as part of a broader investigation on mass multiplication and pharmacological profiling of the species. Plant materials were collected from three sites of Barnawapara, Chhattisgarh, India, during June 2022 to May 2024. Leaves, stems, roots, flowers, bark, seeds, pods, in vitro plants and in vitro seedlings were evaluated for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The DPPH assay was based on the ability of antioxidant constituents to donate hydrogen or electrons to the stable DPPH radical, resulting in a decrease in absorbance at 517 nm. The antioxidant activity showed considerable variation among plant tissues. The highest DPPH inhibition was recorded in in vitro seedlings (83.8%), followed by in vitro plants (81.9%) and bark (80.3%). Roots and leaves exhibited 72.1% and 68.4% inhibition, respectively, whereas pods, stems, flowers and seeds showed comparatively lower activities of 52.7%, 45.2%, 39.6% and 25.4%, respectively. The strong radical scavenging capacity of bark and in vitro-derived tissues corresponded with their relatively higher phenolic and flavonoid contents. In vitro seedlings also showed the highest total phenolic content (23.4 mg/g) and flavonoid content (26.34 mg/g), supporting the association between secondary metabolite accumulation and antioxidant activity. The findings demonstrate substantial antioxidant potential in P. marsupium, particularly in bark and in vitro-derived tissues, and indicate that tissue culture may provide an alternative source of antioxidant-rich plant material.

Keywords: Pterocarpus marsupium, antioxidant activity, DPPH, free radical scavenging, phenolic compounds, flavonoids, in vitro culture, medicinal plant.