Antibacterial activity, phytochemical profiling, and toxicity evaluation of green extracts from Garcinia Mangostana pericarp for food antibacterial applications

This study investigated the antibacterial activity, phytochemical composition, and safety of Garcinia mangostana pericarp (GMP) extracts obtained using aqueous or ethanolic solvents via maceration–filtration or maceration–centrifugation–filtration. Extracts were tested against a panel of 13 bacterial strains, foodborne pathogens, spoilage bacteria, and food-contamination-associated microorganisms and analysed for phenolic and flavonoid content, gas chromatography–mass spectrometry (GC/MS) profiles, and toxicity to Artemia salina. Ethanolic GMP extract from maceration–filtration (GMPEF) inhibited all bacteria except K. pneumoniae and S. sonnei, showing the lowest MIC values (0.70–2.81 mg/mL), the highest extraction yield of 0.129 ± 0.002 g/100 g DW (w/w), and total phenolic content (238.44 ± 0.79 mg GAE/g DW). The upper fraction of ethanolic extract from maceration–centrifugation–filtration (GMPECA) had the highest flavonoid content (4.98 ± 0.001 mg QE/g DW). The GC/MS identified 33 putative compounds (≥ 90% match to the NIST 14 library), including β-sugars, phenolics, and stigmasterol, linked to antibacterial potency. All extracts were non-toxic to A. salina (LC50 > 1 mg/mL); aqueous extracts generally showed higher LC50 values, suggesting a greater safety margin. Principal Component Analysis (PCA) revealed correlations between specific phytochemicals and antibacterial performance, providing a possible chemical basis for selecting extracts. The GMPEF is well-suited in contexts where higher antibacterial activity is desired, and solvent removal is manageable, whereas GMPWCB offers a safer alternative when prioritising a conservative safety profile. While these findings indicate the potential of GMP extracts as sustainable, low-cost antibacterial agents from fruit by-products, further validation in mammalian systems and real food matrices is needed before considering practical applications.