Xanthones and benzophenones from Garcinia griffithii and Garcinia mangostana

Chemical studies on antioxidant mechanism of garcinol: analysis of radical reaction products of garcinol with peroxyl radicals and their antitumor activities

Characterization of tyrosinase inhibitors in the twigs of Cudrania tricuspidata and their structure-activity relationship study.

Phloroglucinols, depsidones and xanthones from the twigs of Garcinia parvifolia

An acetone extract of the leaves of Garcinia oblongifolia showed antiviral activity against enterovirus 71 (EV71) using a cytopathic effect inhibition assay. Bioassay-guided fractionation yielded 12 new prenylated benzoylphloroglucinols, oblongifolins J-U (1-12), and five known compounds. The structures of 1-12 were elucidated by spectroscopic analysis including 1D- and 2D-NMR and mass spectrometry methods. The absolute configurations were determined by a combination of a Mosher ester procedure carried out in NMR tubes and ECD calculations. Compared to ribavirin (IC50 253.1 μM), compounds 1, 4, and 13 exhibited significant anti-EV71 activity in vitro, with IC50 values of 31.1, 16.1, and 12.2 μM, respectively. In addition, the selectivity indices of these compounds were 1.5, 2.4, and 3.0 in African green monkey kidney (Vero) cells, respectively.

Prenylated benzoylphloroglucinols and xanthones from the leaves of Garcinia oblongifolia with antienteroviral activity.

Constituents of three EtOH extracts of the stem bark of Garcinia assigu LANTB., Garcinia dulcis (ROXB.) KURZ., and Garcinia latissima MIQ., belonging to the Guttiferae, collected in Central Province of Papua New Guinea, were studied. A novel depsidone named garcinisidone-A (1), six new xanthones named assiguxanthone-A (3) and -B (9) and dulxanthone-A (4), -B (6), -C (7), and - D (11), and four new pyranoxanthones named latisxanthone-A (13), -B (14), -C (15), and -D (16) were isolated, as well as some known xanthone, benzophenone, chromone, and biflavanone derivatives, and their structures were elucidated by spectroscopic methods. Among these components, garcinisidone-A (1) is the first example of a depsidone derivative having a five-carbon unit (prenyl) as a substituent to be found in nature. Latisxanthone-B (14) was found to contain a hydroperoxy moiety in the molecule. This is the second example of a xanthone hydroperoxide to be found in nature.

Yuko Kawai

Papers

A Novel Depsidone and Some New Xanthones from Garcinia species