PHYTOCHEMICAL SCREENING, BIOASSAY-GUIDED FRACTIONATION, ANTIMICROBIAL EVALUATION, AND IN SILICO MOLECULAR DOCKING STUDIES OF BIOACTIVE FRACTIONS FROM ANNONA SQUAMOSA LEAVES

Dr. Sonali G. Banpure, Dr. Pramod L. Ingale, Pooja S. Shinde*, Rahul D. Kalyankar, Karan S. Karpe

Annona squamosa L. is a popular medicinal plant with appreciable biological effects and a diverse phytochemical profile. The present study aimed to bridge the gap between computational in silico prediction and experimental in vitro confirmation by evaluating the bioassay-guided fractionation, purification, and antibacterial activity of bioactive fractions of A. squamosa leaves. Four phytochemicals, anonaine, catechin, kaempferol, and rutin, which are commonly reported in A. squamosa leaves, were selected for molecular docking experiments against the microbial target proteins (1KZN, 1C14, 3JSU, and 6XYU). Rutin showed the highest binding affinity with a significant score of –10.36 kcal/mol followed by anonaine at –7.79 kcal/mol. Bioactive fractions were obtained by Soxhlet extraction with ethanol and purified using column and thin-layer chromatography (TLC). Phytochemical screening of the purified fraction demonstrated high concentrations of alkaloids, flavonoids, tannins, and phenolic compounds. The purified fraction exhibited a zone of inhibition of 19 mm in the antimicrobial assay against Escherichia coli, which was significantly higher than that of the crude extract (13 mm) and comparable to that of the standard antibiotic ciprofloxacin (28 mm). These findings highlight the potential of A. squamosa as a sustainable source for developing natural antibacterial agents and provide a molecular basis for its traditional use in treating infectious disorders.