Garcinia mangostana L. is widely recognized for its traditional medicinal uses and growing relevance in the nutraceutical sector. This research endeavor is designed to scrutinize the phytochemical composition and cytotoxic effects of an alcoholic extract derived from the pericarps of G. mangostana (ME) on leukemic cell lines.Garcinia mangostana L. pericarps were subjected to ethanol extraction, and subsequent compound identification was conducted via Capillary Liquid Chromatography-Electrospray Ionization-Quadrupole Time-of-Flight Tandem Mass Spectrometry (CapLC-ESI-QTOF-MS/MS). In parallel, the extract was fractionated through High-Performance Liquid Chromatography (HPLC). Furthermore, transformed U937 and Jurkat, and normal HUVEC human cell lines were exposed to varying concentrations of the extract to assess cell proliferation, viability, cytotoxicity, and apoptotic DNA damage.Investigations confirmed the presence of various xanthones, including β-mangostin, α-mangostin, and garcinone E. Significantly, ME displayed pronounced cytotoxic effects specifically on leukemic cells, distinguishing its impact on malignant cells as opposed to non-malignant ones, and facilitated apoptotic DNA fragmentation. Moreover, the whole extract consistently displayed greater cytotoxicity compared to individual fractions.According to the results obtained ME selective cytotoxicity against cancer cell lines and greater biological activity than the single compounds in the extract. These findings underscore ME's potential in cancer prevention, complementing dietary strategies ahead of pharmaceutical interventions.