The cytotoxic activity of α-mangostin in human cancer cells involves the upregulation of MOAP-1 tumor suppressor and activated BAX as well as the interaction of the upregulated MOAP-1 with act-BAX, leading to apoptosis signaling, including BAX oligomerization, downregulation of BCL-XL, the release of mitochondrial Cyt.C, and caspase activation. Here, MOAP1 is linked to cancer.