Isolation, structural elucidation and in-silico screening of bioactive phytocompounds from Averrhoa carambola L. (Star Fruit) leaves as potential anti-inflammatory prophylaxis

Averrhoa carambola (Oxalidaceae) also known as star fruit is a tropical plant rich in bioactive secondary metabolites, particularly polyphenols and flavonoids. In this study, a 95% ethanolic leaf extract was subjected to column chromatography for isolation of phytoconstituents, followed by structural elucidation using FTIR, 1H NMR, 1³C NMR, and mass spectroscopy. Four compounds β-sitosterol, 8-methyl-N-vanillyl-6-nonenamide, protocatechuic acid, and sinapic acid were identified. Molecular docking (AutoDock Vina) against key inflammatory targets (1PXX,1KVO and 1Q41) revealed that β-sitosterol exhibited the highest binding affinity towards cyclooxygenase-II (COX-2; PDB ID: 1PXX) with a score of -9.3 kcal/mol, exceeding diclofenac (-8.4 kcal/mol) under identical conditions. Moderate interactions were observed with phospholipase A2 (-6.2 kcal/mol), while other compounds showed lower affinities (-5.7 to -6.8 kcal/mol). Molecular dynamics simulation of the COX-2-β-sitosterol complex indicated stable binding throughout the simulation. These findings highlight β-sitosterol as a promising anti-inflammatory lead, providing a computational basis for further experimental validation.