New benzophenones and a dihydroflavanonol from Garcinia mangostana pericarps and their antioxidant and cytotoxic activities

Two new benzophenone derivatives [2,4,6,3',4',6'-hexahydroxybenzophenone (5) and 6-O-beta-D-glucopyranosyl2,4,6,3',4',6'-hexahydroxybenzophenone (8)], one new dihydroflavanonol derivative [2R,3R-5,7-dihydroxy-8C-beta-D-glucopyranosyl-4'-methoxy-2,3-dihydroflavon-3-ol (9)], and six known metabolites [beta-mangostin (1), garcinone E (2), alpha-mangostin (3), mangostanaxanthone IV (4), epicatechin (6), and garcimangosone D (7)] were separated from the EtOAc fraction of Garcinia mangostana (Clusiaceae) pericarps. Their characterization was accomplished by various spectroscopic techniques and by comparison with the literature data. Compounds 5, 8, and 9 were assessed for their antioxidant potential using DPPH assay. They exhibited significant antioxidant activity with IC(50)s 21.6, 43.5, and 36.4 mu g/mL, respectively in comparison to butylated hydroxyanisole (BHA) (IC50 26.3 mu g/mL). In addition, the cytotoxic activities of 5, 8, and 9 were assessed towards lung carcinoma (A549), colorectal adenocarcinoma (HCT-116), and breast adenocarcinoma (MCF-7) cell lines. Compound 5 possessed cytotoxic potential towards A549 (IC50 1.4) and HCT-116 (IC50 1.8 mu M) in comparison to that of doxorubicin (IC(50)s 0.6 and 0.2 mu M, respectively). While 8 exhibited activity with IC50 1.9 mu M towards HCT-116. These findings could provide evidence to support the traditional use of G. mangostana for the treatment of chronic or degenerative illnesses.