Solvent‑Dependent Phytochemical Profiling and Total Reducing Capacity of Pongamia pinnata (L.) Pierre

Abstract

Oxidative stress is implicated in numerous chronic diseases, driving the search for natural reducing agents from medicinal plants. Pongamia pinnata (L.) Pierre is a traditional medicinal tree; however, comparative data on the influence of solvent polarity and plant tissue on its phytochemical composition and reducing capacity remain limited. This study compared the phytochemical profiles and total reducing capacity of leaf, stem and seed extracts obtained using methanol (organic) and water (aqueous), with the aim of identifying the optimal plant part–solvent combination. Shade-dried plant materials were macerated in methanol or water (1:10 w/v, 48 h). Qualitative assays (Wagner’s test for alkaloids; lead acetate test for flavonoid-reactive compounds) and quantitative analyses, including total protein (Lowry), soluble carbohydrates (phenol–sulfuric acid), reducing sugars (DNS), total phenolic content (Folin–Ciocalteu) and total reducing capacity (phosphomolybdenum), were performed. All measurements were conducted in triplicate (n = 3). Data were analyzed using one-way ANOVA followed by Tukey’s HSD test (p < 0.05). Alkaloids and flavonoid-reactive compounds were detected in all extracts. The aqueous seed extract exhibited the highest mean total phenolic content (2.193 mg GAE/mL) and reducing capacity (1.337 mg TE/mL). However, standard deviations exceeding the corresponding means indicate substantial variability and limited statistical robustness. Both assays are non-specific and reflect total reducing capacity rather than direct radical scavenging activity. These findings provide preliminary evidence that aqueous seed extracts are enriched in polar reducing compounds, supporting traditional usage. Further validation using radical-specific assays (e.g., DPPH, ABTS), increased replication (n ≥ 6) and bioactivity-guided fractionation is required before potential nutraceutical application.