The exocarp of Garcinea mangostana was dissolved in various organic solvents namely Methanol, Ethanol and Butanol was tested for antimicrobial, antiproliferative and/or cytotoxic activity. Significant antimicrobial activity was found with Garcinea mangostana against Pseudomonas aeroginosa and Staphylococcus aureus. The extracts were also found to possess antifungal activity against Candida albicans. Out of different extracts tested, methanolic extract was found to be the most active against Pseudomonas aeruginosa followed by S. aureus and P.mirablis. Total Polyphenolic content ranged from 102.4to 138.6mg GAE/g of extract. Among the three solvent extracts, methanol extract showed maximum Polyphenol content at 6 hr extraction time followed by ethanol and butanol respectively. The extractive yield of sample was higher in methanol, compared to ethanol and butanol. The yield obtained decreased with decrease in polarity. The LD50 values of the plant extract against HEp2 cells was determined by MTT assay. The LD50 value of Garcinea mangostana was ≥ 120µg,92 µg and 85 µg for, methanol, ethanol, and butanol extracts respectively and the study revealed that the exocarp possessed free radical scavenging activity. Methanolic extract, Ethanolic extract, Butanolic extract were found to reduce the GSH level than the control. TBARS of stress induced HEp2 cells was reduced in the presence of Ethanolic extract and Butanolic extract. All extracts were found to reduce GPx activity.