Xanthone

About: Xanthone is a research topic. Over the lifetime, 1639 publications have been published within this topic receiving 25870 citations. The topic is also known as: 9-oxo-xanthene & Diphenyline ketone oxide.

Xanthones from leaves of Calophyllum inophyllum Linn

Abstract: To study the xanthones from the leaves of Calophyllum inophyllum Linn., several chromatography methods were employed to isolate the constituents. Investigation on the CHCl3 extract led to the isolation of a new xanthone named inophyxanthone A (1) and four known compounds, which were pancixanthone A (2), gerontoxanthone B (3), jacareubin (4) and pyranojacareubin (5). Among them, compound 2 was obtained from this plant firstly, and compound 3 was obtained for the first time from this genus. The structure of inophyxanthone A (1) was identified as 1, 3, 5-trihydroxy-2-(1, 1-dimethylallyl)xanthone by spectral analysis.

Induction of calcium release from sarcoplasmic reticulum of skeletal muscle by xanthone and norathyriol

Abstract: 1. Effects of xanthone and its derivative, 1,3,6,7-tetrahydroxyxanthone (norathyriol), on Ca2+ release and ryanodine binding were studied in isolated sarcoplasmic reticulum (SR) vesicles from rabbit skeletal muscle. 2. Both xanthone and norathyriol dose-dependently induced Ca2+ release from the actively loaded SR vesicles which was blocked by ruthenium red, a specific Ca2+ release inhibitor, and Mg2+. 3. Xanthone and norathyriol also dose-dependently increased apparent [3H]-ryanodine binding. Norathyriol, but not xanthone, produced a synergistic effect on binding activation when added concurrently with caffeine. 4. In the presence of Mg2+, which inhibits ryanodine binding, both caffeine and norathyriol, but not xanthone, could restore the binding to the level observed in the absence of Mg2+. 5. Xanthone activated the Ca(2+)-ATPase activity of isolated SR vesicles dose-dependently reaching 70% activation at 300 microM. 6. When tested in mouse diaphragm, norathyriol potentiated the muscle contraction followed by twitch depression and contracture in either a Ca(2+) -free bathing solution or one containing 2.5 mM Ca2+. These norathyriol-induced effects on muscle were inhibited by pretreatment with ruthenium red or ryanodine. 7. These data suggest that xanthone and norathyriol can induce Ca2+ release from the SR of skeletal muscle through a direct interaction with the Ca2+ release channel, also known as the ryanodine receptor.