BSA Protein Denaturation Inhibition by Averrhoa bilimbi L. Fruit Ethanol Extract: In Vitro Study

Abstract

Inflammation is a protective physiological response; however, excessive or persistent inflammation may contribute to tissue dysfunction and disease. Plant-derived secondary metabolites have been widely explored as potential anti-inflammatory agents with fewer long-term adverse effects than conventional drugs. This study investigated the phytochemical profile and in vitro anti-inflammatory activity of the 96% ethanol extract of Averrhoa bilimbi L. fruit using the bovine serum albumin (BSA) protein denaturation inhibition assay. The extract was obtained by maceration, followed by qualitative tube-based phytochemical screening. Anti-inflammatory activity was evaluated at final assay concentrations of 20, 40, 60, 80, and 100 ppm, with sodium diclofenac as a positive control (10–40 ppm). The mixture containing BSA was incubated at 25 °C for 30 min, heated at ~72 °C for 5 min, and absorbance was measured at 660 nm. Phytochemical screening indicated the presence of flavonoids, alkaloids, and tannins. The extract inhibited protein denaturation in a concentration-dependent manner with inhibition percentages of 20.67%, 45.33%, 50.13%, 55.14%, and 60.22% (20–100 ppm), yielding an IC₅₀ of 60.94 µg/mL (≈ppm). Sodium diclofenac showed stronger inhibition with an IC₅₀ of 8.20 µg/mL. These findings support the phytochemical potential of A. bilimbi fruit extract as a preliminary in vitro anti-inflammatory candidate, warranting further fractionation and mechanistic studies to identify active constituents and confirm activity beyond this screening model.