Phytochemical Profiling, In Vitro α-Amylase Inhibitory and Antioxidant Activities of Madhuca longifolia Leaf and Bark Extracts with Molecular Docking Analysis

Plant-derived phytochemicals are increasingly investigated for their antioxidant and enzyme-inhibitory activities as potential sources of bioactive compounds. The present study evaluated the phytochemical composition, antioxidant activity, and in vitro α-amylase inhibitory activity of Madhuca longifolia leaf and bark extracts, followed by GC-MS profiling and exploratory computational analyses of the methanolic leaf fraction. Moreover, we elucidated the ADME properties of GC-MS-putatively identified compounds and their computational molecular interactions with α-amylase. The leaves and barks were sequentially extracted using n-hexane, DCM, EtOAc, MeOH, and water. The qualitative phytochemical analysis and antioxidant activity were determined via DPPH, ABTS, and FRAP assays. Furthermore, the MeOH fraction of M. longifolia leaves was subjected to GC-MS analysis to identify the secondary metabolites. The putatively identified compounds were further subjected to ADME analysis and computational molecular interaction studies with α-amylase. Phytochemical screening indicated the presence of several tested phytochemical classes in the MeOH and aqueous fractions of the leaf and bark extracts. The MeOH and aqueous fractions of the leaf extract showed IC50 values of 8.67 and 10.51 µg/mL, respectively, against DPPH, whereas the corresponding bark fractions showed IC50 values of 8.21 and 8.15 µg/mL, respectively. A similar trend was observed in the ABTS assay, where the MeOH and aqueous fractions of the leaf extract exhibited IC50 values of 4.32 and 4.68 µg/mL, respectively, while the corresponding bark fractions showed IC50 values of 4.44 and 5.40 µg/mL, respectively. The maximum α-amylase inhibitory potential was observed in the MeOH fraction of the leaf extract, and global nonlinear enzyme kinetic analysis showed a pattern consistent with competitive inhibition. The in silico molecular docking analysis predicted that 6-methylheptanoic acid from the MeOH fraction of the leaf extract may interact with the catalytic site of human α-amylase, with a Glide score of −6.132. In conclusion, the findings provide preliminary evidence of antioxidant and in vitro α-amylase inhibitory activities of the MeOH fraction of M. longifolia leaf extract and support its consideration as a preliminary lead for further investigation. Further studies involving quantitative chemical characterization, isolation and validation of individual constituents, cellular and pharmacodynamic evaluation, experimental toxicity assessment, and in vivo efficacy studies are required to establish their relevance to glucose metabolism and diabetes-related outcomes.