Introduction. Mangosteen (Garcinia mangostana) is a tropical fruit that isfamous for its edible pulp. This edible pulp makes up only 30% of the total fruit, whilethe remaining pericarp and seed are regarded as waste. Facing the increasing public demandfor naturally safe foods and products, our study aimed to elucidate the antioxidantcapacity and antibacterial activity of different parts of mangosteen, including thepericarp, pulp and seed. Materials and methods. The antioxidant capacities ofmangosteen’s pericarp, pulp and seed extracts were determined using the ferric reducingantioxidant power (FRAP) assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, whereasantibacterial activity was determined using the disc diffusion method.Results. The pericarp extract exhibited higher antioxidant capacities thanthose of pulp and seed extracts, with a Trolox equivalent antioxidant capacity (TEAC)value of 122.00 µM·g–1 and ferrous sulphate equivalent antioxidant capacity (FEAC) valueof 18.99 mM·g–1. All mangosteen extracts showed strong inhibition against Staphylococcus aureus ATCC11632, while only the pericarp extract was effectiveagainst Bacillus cereus ATCC10876. No inhibition againstEscherichia coli ATCC10536 was observed. Conclusion. Theoutcomes of our study could facilitate future application of mangosteen waste as abiopreservative in the food industry.