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.

Optimisation of retention of mangiferin in cyclopia subternata during preparation for drying and storage of green honeybush and development of nir spectroscopy calibration models for rapid quantification of mangiferin and xanthone contents

Abstract: Extraction efficiency of soluble solids (SS), total polyphenols (TP) and xanthones (AlCl3 assay) from dried, green Cyclopia subternata, as affected by mass-solvent ratio, extraction time and solvents, was investigated. In addition the effect of solvent composition on extraction of mangiferin and hesperidin was determined. Extraction of 5 g plant material as opposed to 0.5 and 1 g resulted in lower recoveries of SS, TP and xanthones (P contact time, where after it remained constant (P>0.05). Water, 33% acetonitrile, ethanol (50, 80 and 100%), methanol (50 and 100%) and 70% acetone were investigated as extraction solvents. Extraction for 30 min with 33% acetonitrile on a steam bath or 50% ethanol at 64°C proved to be the most effective for extraction of SS, TP and xanthones, while 33% acetonitrile was most effective in extracting hesperidin from C. subternata. Both solvents were less effective than 70% acetone in extracting mangiferin. The total antioxidant activity (TAA) of C. subternata, as determined for water extracts, correlated poorly (r = 0.54) with the mangiferin content determined by HPLC. A moderate correlation (r = 0.85) was, however, obtained for TAA and TP content. The potential of using the aluminium chloride (AlCl3) colorimetric method to determine the mangiferin content in green C. subternata was also undertaken. A moderate correlation (r = 0.87) was found for the xanthone content of the plant material determined using the AlCl3 colorimetric method and mangiferin content quantified by HPLC (y = 1.2x + 0.54) when extracted with hot water. When using 33% acetonitrile a weaker correlation (r = 0.74; y = 1.3x + 0.87) was found between the xanthone and mangiferin content. The xanthone content (determined by AlCl3) of the plant material as extracted by the two solvents, correlated well (r = 0.91). Good correlations were also obtained, when comparing extractions with water and 33% acetonitrile, for determination of the SS (0.94) and mangiferin contents (r = 0.97) of the plant material. Near infrared (NIR) spectroscopy was applied to develop calibration models to predict mangiferin and xanthone contents of dried, green C. subternata plant material. Samples included stems, leaves or stems+leaves to extend the variation range of the samples. The NIR spectroscopy calibration models

Xanthone glycosides from Tibetan herb Halenia elliptica.

Abstract: OBJECTIVE To isolate and identify the active xanthone glycosides in Halenia elliptica. METHOD The compounds were isolated by column chromatography, semi-preparative high performance liquid chromatography and related techniques. Their structures were elucidated through spectroscopic analysis (NMR and MS). RESULT Six xanthone glycosides were isolated and identified as: 2,3,5-trimethoxy-1-O-primeverosyloxyxanthone (1), 2, 3, 4, 5-tetramethoxy-1-O-primeverosyloxyxanthone (2), 2, 3, 5, 7-tetramethoxy-1-O-primeverosyloxyxanthone (3), 2, 3, 7-trimethoxy-1-O-primeverosyloxyxanthone (4), 2, 3, 4, 7-tetramethoxy-1-O-primeverosyloxyxanthone (5), and 2, 3, 4, 5, 7-pentamethoxy-1-O-primeverosyloxyxanthone (6). CONCLUSION Compounds 4-6 were isolated from this plant for the first time.

Xanthone analogue of geiparvarin.

Abstract: The synthesis and the pharmacological properties of the xanthone analogue of geiparvarin, a naturally occurring antitumor coumarin, are described. Xanthon-Analogon des Geiparvarins Die Synthese und die pharmakologischen Eigenschaften des Xanthon-Analogon, eines in der Natur vorkommenden antitumoralen Cumarins, Geiparvarin, werden beschrieben.

Cladoxanthones A and B, Xanthone-Derived Metabolites with a Spiro[cyclopentane-1,2'-[3,9a]ethanoxanthene]-2,4',9',11'-tetraone Skeleton from a Cladosporium sp.

Abstract: Cladoxanthones A (1) and B (2), two xanthone-derived metabolites featuring a new spiro[cyclopentane-1,2'-[3,9a]ethanoxanthene]-2,4',9',11'(4a'H)-tetraone skeleton, were isolated from cultures of the ascomycete fungus Cladosporium sp., together with the known mangrovamide J (3). Their structures were elucidated primarily by NMR experiments. The absolute configurations of 1 and 2 were assigned by X-ray crystallography using Cu Kα radiation. Compound 1 could be generated from the hypothetical precursors related to α-methylene ketone and dihydro-xanthone via a Diels-Alder reaction, while 2 could be an oxidative coupling product resulting from 1 and 3. Compounds 1 and 2 showed weakly cytotoxic effects.

Cytoprotective and Anti-genotoxic Effects of Xanthone Derivatives from Garcinia mangostana Against H2O2 Induced PBMC Cell and Blood Leukocytes Damage of Normal and Type 2 Diabetes Volunteers

Abstract: Hyperglycemia is well-known for inducing cellular oxidative damage in type II diabetes (T2D) patients. This research addressed the cytoprotective and anti-genotoxic effect of xanthone derivatives from Garcinia mangostana against hydrogen peroxide (H2O2)-induced human peripheral blood mononuclear cell (PBMC) and blood leukocytes damage of the normal and T2D volunteers. The cytoprotective effects of an aqueous extract of xanthone (100 and 200 µg/mL) was assessed on cell viability and free radical scavenging activity using the trypan blue exclusion method on PBMC cells. Malondialdehyde (MDA) levels and lactate dehydrogenase (LDH) activity were measured as cellular oxidative damage markers and estimated from culture medium of PBMCs of normal and T2D volunteers. The anti-genotoxicity was assessed as the protective effect of xanthone against H2O2-induce DNA damage of blood leukocytes of the normal volunteers following comet assay technique. Xanthone and Gallic acid (control) concentrations 100, 200 and 100 µg/mL significantly (P < 0.05) protected from H2O2 (20 mM)-induced oxidative damage of PBMCs. It was confirmed by increased cell viability and free radical scavenging activity coupled with the decreased MDA and LDH levels in cell culture medium compared to H2O2 (20 mM)-treated group. In H2O2 (40 mM)-induced blood leukocytes of normal volunteers, different concentration xanthone (50 - 500 µg/mL) significantly (P < 0.05) improved the anti-genotoxicity effect compared to negative/positive control group by lowering comet formation. Xanthone treatments on PBMCs and blood leukocytes of the normal and T2D volunteers could attenuate the H2O2-induced cellular oxidative damage and cell death via exhibiting antioxidant and free radical scavenging activities.