Immunomodulatory and anticancer activities of phenolics from Garcinia mangostana fruit pericarp

The methanolic extract of Garcinia mangostana fruit pericarp was partitioned into butanol and water fractions in this work. Three major phenolics were purified and identified as P1 [1,3,6,7-tetrahydroxy-2,8-(3-methyl-2-butenyl) xanthone], P2 [1,3,6-trihydroxy-7-methoxy-2,8-(3-methyl-2-butenyl) xanthone] and P3 (epicatechin). Strong antioxidant activities were detected for P1–P3. In vitro cell proliferation trials indicated that P1 and P3 exhibited good immunomodulatory activities when 7.5 μg/ml was used. Furthermore, P1 and P3 showed good cytotoxicities against human breast cancer cells (MCF-7) and human colon cancer cells (LOVO). P1 exhibited the maximal cytotoxicity of 73.06% against MCF-7 cells and of 46.27% against LOVO cells when 62.5 μg/ml was used. The cytotoxicities of P1, P2, P3 and paclitaxel against normal embryonic lung fibroblast cells (HELF) were in a decreasing order: paclitaxel > P3 > P1 > P2. These results suggested that P1 and P3 could be used as a potential anticancer agent.