Bioautography-Guided Thin Layer Chromatography and Fractionation of Garcinia mangostana Pericarp Extract for Antibacterial and Toxicity Evaluation

This study aims to explore the antibacterial activities of Garcinia mangostana pericarp (GMP) crude extract and partially purified extract. The antibacterial activity of both crude and partially purified extracts was assessed using Thin-Layer Chromatography (TLC) bioautography, Minimum Inhibitory Concentration (MIC), and toxicity assays. The GMP extract was separated via TLC using various eluents, including 5% ethyl acetate in petroleum ether, 1:3, 1:1, and 3:1 hexane:ethyl acetate, 1:1 hexane:diethyl ether, diethyl ether, 1:1 diethyl ether: methanol, Milli-Q water, and 0.1% formic acid in acetonitrile. A fractionation approach was used to evaluate the antibacterial activity of compounds present in the solvent fractions of the GMP extract. The antibacterial efficacy of the crude and partially purified GMP extracts was evaluated using MIC assays against B. cereus, C. perfringens, E. coli, L. monocytogenes, S. aureus, S. pneumoniae, and V. vulnificus. The GMP crude extract demonstrated the strongest antibacterial activity and the highest LC50 value (2.75 ± 0.15 mg/mL), indicating lower toxicity than partially purified GMP extracts. The L. monocytogenes was identified as the most susceptible microorganism to the GMP crude extract (MIC = 0.35 mg/mL), while B. cereus showed the least sensitivity (MIC = 11.25 mg/mL). These results support the potential use of GMP as a source of natural antibacterial agents, with possible applications in food preservation and safety.