Many compounds isolated from mangosteen fruit and pericarp have been evaluated in lab studies. Xanthones alpha- and beta-mangostins, and garcinone B exhibit strong inhibitory effects against Mycobacterium tuberculosis  ⁽³⁾, as well as aromatase-inhibitor activity ⁽¹⁴⁾. Alpha- and gamma-mangostins act as histamine and serotonin receptor blockers ⁽⁸⁾ and inhibit HIV-1 protease ⁽⁹⁾. In animal models, they reduced major features of allergic asthma including airway inflammatory cell recruitment and hyperresponsiveness, increased Th2 cytokine levels, and attenuated increases in phosphoinositide 3-kinase (PI3K) activity, phosphorylation of Akt, and NF-kappaB ⁽²⁶⁾. The ability of alpha-mangostin to inhibit fatty acid synthase may occur via stronger action on the ketoacyl synthase domain and weaker effects on the acetyl/malonyl transferase domain ⁽²²⁾. It also reduced prostaglandin synthesis by inhibiting COX-1 and -2 enzyme activities ⁽⁵⁾, and prevented oxidative damage of LDL by functioning as a free-radical scavenger ⁽⁷⁾. The compound isogarcinol isolated from mangosteen induces anti-inflammatory and immunosuppressant effects in animal models ^(30) (31). Mangosteen extract may have antiobesity effects by increasing AMP-activated protein kinase and Sirtuin 1 activities in the liver ⁽⁴²⁾.

Chemopreventive properties of mangosteen xanthones against specific human cancer cell lines have also been demonstrated, including: alpha-mangostin in leukemia ^{(1) (6) (32)}, breast ^(33) (34), gastric ⁽³⁵⁾, and pancreatic cancer cells ^(36) (37); gartanin in urinary bladder cancer ⁽³⁸⁾; and gamma-mangostin ⁽³⁹⁾ and garcinone E ⁽¹⁰⁾ in liver cancer cells. Extracts from the pericarp of mangosteen also exhibit antioxidant ⁽¹³⁾, antiproliferative, and apoptotic effects ⁽¹¹⁾.

The preventive effect of alpha-mangostin on cisplatin-induced apoptotic death is associated with the inhibition of p53 expression and generation of reactive oxygen species ⁽²³⁾. Alpha-mangostin inhibited growth of leukemia HL60 cells by inducing caspase-3-dependent apoptosis ^(1) (6). It reduced matrix metalloproteinase MMP-2 and -9 expression, increased E-cadherin expression, and suppressed the ERK signaling pathway in pancreatic cancer cell lines ⁽³⁶⁾. In chronic myeloid leukemia cells, it induced autophagy via increased expression of the autophagosome marker LC-3II and accumulation of autophagic vacuoles, in addition to antiproliferative and apoptotic effects ⁽³²⁾. Another study also attributes the antitumor activity of alpha-mangostin to autophagy and not endoplasmic reticulum stress induction ⁽²⁴⁾.

Beta-mangostin decreased the proliferation of human cervical cancer HeLa cell by inhibiting cellular polymerases ⁽⁴³⁾. Gamma-Mangostin demonstrated free radical scavenging activity in human liver cancer cells ⁽³⁹⁾. In bladder cancer cell lines, activities of gartanin suggest mTOR pathway inhibition, downregulation of Bcl-2 expression, and p53 pathway activation leading to apoptotic induction ⁽³⁸⁾.