Cytotoxic effect of xanthones from pericarp of the tropical fruit mangosteen (Garcinia mangostana Linn.) on human melanoma cells

Mangosteen (Garcinia mangostana Linn.) is a tropical tree from South East Asia and its fruit pericarp is a well-known traditional medicine. In this study, the cytotoxic effect of three xanthone compounds (α-mangostin, γ-mangostin, and 8-deoxygartanin) from mangosteen pericarp was investigated using the human melanoma SK-MEL-28 cell line. Significant dose-dependent reduction in % cell viability was induced. γ-Mangostin and 8-deoxygartanine at 5μg/ml increased the cell cycle arrest in G ₁ phase (90% and 92%) compared with untreated cells (78%). All compounds induced apoptosis, of the highest being α-mangostin at 7.5μg/ml that induced 59.6% early apoptosis, compared to 1.7% in untreated cells. The apoptotic effect of α-mangostin was via caspase activation and disruption of mitochondrial membrane pathways as evidenced by 25-fold increased caspase-3 activity and 9-fold decreased mitochondrial membrane potential when compared to untreated cells. In conclusion, these xanthones, especially α-mangostin, are potential candidates as anti-melanoma agents.