Chem. Pharm. Bull. 54(3) 301—305 (2006)

of the tropical tree Garcinia mangostana L. (Clusiaceae), regarded as “the queen of fruit,” have demonstrated interesting biological activities. Studies have been conducted to examine the anticancer properties of the extracts or xanthones obtained from the fruit hulls of this plant species against colon preneoplastic lesions, DNA topoisomerases I and II, human leukemia (HL60, K562, NB4, U937, P3HR1, and Raji), hepatoma (HCC36, TONG, HA22T, Hep 3B, HEpG2, and SK-HEp-1), lung (NCI-Hut 125, CH27-LC-1, H2981, and Calu-1), and gastric carcinomas (AZ521, NUGC-3, KATO-III, and AGS), and human breast cancer SKBR3 cells. Our interest has been focused on the isolation of structurally interesting prenylated xanthones and the biological activities of intermediates at various stages of fruit maturity. In our previous study, the isolation of 17 xanthones including three new xanthones, mangostenol and mangostenones A and B, from the green fruit (14-week maturity stage) of this plant and their antituberculosis activity were already described. In a continuation of this work, the EtOAc-soluble extract obtained from the young fruit (7-week maturity stage) of G. mangostana was subjected to a chemical investigation leading to the isolation and structural elucidation of three new prenylated xanthones, mangostenones C (1), D (2), and E (3), in addition to 16 previously reported xanthones, thwaitesixanthone (4), demethylcalabaxanthone (5), garcinone B (6), compound 7, b-mangostin (8), 8-desoxygartanin (9), gartanin (10), garcinone E (11), the major metabolite a-mangostin (12), mangostinone (13), the second major metabolite g-mangostin (14), mangostanol (15), mangostanin (16), garcinone D (17), garcinone C (18), and the third major metabolite 11-hydroxy-1-isomangostin (19). We here report on the structural elucidation of the three new compounds and the in vitro cytotoxic activities of xanthones 1—19 against three human cancer cell lines, epidermoid carcinoma of the mouth (KB), breast cancer (BC-1), and small cell lung cancer (NCIH187).