Seasonal variation in phytochemical composition, quantitative analysis, and antioxidant activity of bulb extract from Urginea indica (Roxb.) Kunth

Urginea indica (Roxb.) Kunth is an important medicinal geophyte that has been traditionally used to treat a wide range of ailments, particularly cardiac and respiratory disorders. Its therapeutic value is largely attributed to the rich diversity of bioactive secondary metabolites present in the plant. The aim of this study is to investigate the seasonal effect in the phytochemical constituents of the bulb of Urginea indica (Roxb.) Kunth, both qualitatively and quantitatively, as well as the antioxidant activity of the methanolic plant extract. In this study, bulb samples were collected across three distinct seasons (rainy, winter, and summer) and then extracted using aqueous, acetone, and methanol solvents through the Soxhlet apparatus. The antioxidant activity was analyzed by the DPPH assay. Quantitative analysis revealed that phenolic (3.799 mg GAE/g) and flavonoid (0.922 mg QE/g) contents were highest in winter, followed by summer (1.550 mg GAE/g and 0.800 mg QE/g, respectively), and their lowest concentrations in the rainy season (0.547 mg GAE/g and 0.405 mg QE/g). On the other hand, steroid (7.6 µg/g) and alkaloid (43.94 %) content were highest in the rainy season, reflecting their role in plant defense and growth. Antioxidant activity, determined by the DPPH assay, was concentration-dependent, scavenging activity with the methanolic extract having an IC 50 value of 584.172 µg/ml, although less potent than ascorbic acid (IC 50 = 36.961 µg/ml). The observed activity supports the potential medicinal relevance of U. indica as a natural source of bioactive compounds. This research highlights the seasonal and solvent-dependent variation in the distribution of bioactive compounds in U. indica bulbs, indicating their potent antioxidant activity and potential medicinal value.