Benzopyran, biphenyl, and tetraoxygenated xanthone derivatives from the twigs of Garcinia nigrolineata

One new benzopyran, nigrolineabenzopyran A (1), two new biphenyls, nigrolineabiphenyls A and B (2, 3), and four new tetraoxygenated xanthones, nigrolineaxanthones T-W (4-7), were isolated from the crude methanol extract of the twigs of Garcinia nigrolineata along with 11 known xanthones. The xanthones isolated from the twigs as well as those from the stem bark were evaluated for antibacterial activity against methicillin-resistant Staphylococcus aureus. Nigrolineaxanthone F, latisxanthone D, and brasilixanthone showed significant activity, with an equal MIC value of 2 microg/mL.     

Chemical constituents of Garcinia fusca: structure elucidation of eight new xanthones and their cancer chemopreventive activity

We describe the isolation and spectrometric structure elucidation of eight new xanthones, fuscaxanthone A (1), B (2), C (3), D (4), E (5), F (6), G (7), and H (8), together with eight known xanthones from the stem bark of Garcinia fusca collected in Thailand. All the new xanthones were shown to have a terpenoid (prenyl and/or geranyl) side chain(s) in their molecules. We also present the results of a primary screening of the inhibitory effects of eight xanthones (9-16) isolated as major components of this plant on 12-O-tetradecanoylphorbol-13-acetate induced Epstein-Barr virus early antigen activation in Raji cells.     

Chemical constituents of Calophyllum brasiliensis: structure elucidation of seven new xanthones and their cancer chemopreventive activity

The first study of chemical constituents of the stem bark of Calophyllum brasilienses collected in Brazil has led to the isolation and identification of seven new xanthones named brasixanthones A (1), B (4), C (5), D (6), E (2), F (3), and G (10), together with 10 known xanthones. Among the xanthones isolated in this study, 4, 5, 6, and 11 were found to exhibit significant inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate induced Epstein-Barr virus early antigen activation in Raji cells.     

Xanthone and sesquiterpene derivatives from the fruits of Garcinia scortechinii

The fruits of Garcinia scortechinii afforded 10 new compounds: four caged-tetraprenylated xanthones (scortechinones Q-T, 1-4), four rearranged xanthones (scortechinones U-X, 5-8), and two sesquiterpene derivatives (scortechterpenes A, B, 9, 10), together with 14 known compounds: one sesquiterpene, two biflavonoids, and 11 caged-polyprenylated xanthones. Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously. All xanthone derivatives were evaluated for antibacterial activity against methicillin-resistant Staphylococcus aureus.     

Caged-triprenylated and -tetraprenylated xanthones from the latex of Garcinia scortechinii

The latex of Garcinia scortechinii has yielded eight new caged-polyprenylated xanthones: two triprenylated (1 and 2) and five tetraprenylated xanthones (3-7) and one degraded caged-tetraprenylated xanthone (8), together with the known scortechinones A (9) and B (10). Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously.     

Prenylated xanthones from the root bark of Cudrania tricuspidata

Four new prenylated xanthones, cudratricusxanthones J-M (1-4), were isolated from the CH2Cl2-soluble extract of the root bark of Cudrania tricuspidata, along with four known prenylated xanthones, isocudraxanthone K (5), cudraxanthone C (6), cudratricusxanthone A (7), and cudraxanthone L (8), and three known prenylated flavonoids, cudraflavone A (9), cudraflavanone A (10), and cudraflavone B (11). The structures of compounds 1-4 were elucidated using spectroscopic methods. Cudratricusxanthone A (7), cudraflavanone A (10), and cudraflavone B (11) showed moderate inhibitory effects on mouse brain monoamine oxidase (MAO) with IC50 values of 88.3, 89.7, and 80.0 microM, respectively.     

Antibacterial xanthones from the leaves of Garcinia nigrolineata

Ten new 1,3,5-trioxygenated xanthones, nigrolineaxanthones J-S (1-10), one new quinone derivative, nigrolineaquinone A (11), and one new isoflavone-like compound, nigrolineaisoflavone A (12), were isolated from the leaves of Garcinia nigrolineata along with four known xanthones and friedelin. Among the xanthones, only nigrolineaxanthone N (5) showed significant antibacterial activity against methicillin-resistant Staphylococcus aureus.     

New phenolics from Polygala fallax

Two new phenolic compounds, polygalolide A (1) and polygalolide B (2), together with three known xanthones were isolated from the roots and stems of Polygala fallax. The structures of 1 and 2 were elucidated on the basis of spectroscopic evidence.     

Three xanthones and a benzophenone from Garcinia mangostana

Investigation of the constituents of Garcinia mangostana has led to the isolation of four new compounds: three minor xanthones, garcimangosone A (1), garcimangosone B (2), and garcimangosone C (3), and a benzophenone glucoside, garcimangosone D (4). The structures of these four compounds were established by spectral (NMR and MS) and chemical methods.     

Cytotoxic prenylated xanthones and the unusual compounds anthraquinobenzophenones from Cratoxylum sumatranum

Six new xanthones, cratoxyarborenones A-F (1-6), were isolated from the leaves, twigs, and/or stem bark of Cratoxylum sumatranum along with the known compound, vismione B (9), as active constituents by bioassay-directed fractionation using the KB human cancer cell line cytotoxicity assay. In addition, two novel anthraquinobenzophenones, cratoxyarborequinones A (7) and B (8), and two known compounds, 2,4,6-trihydroxybenzophenone 4-O-geranyl ether and delta-tocotrienol, were obtained as inactive constituents.