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PubMed1994

Xanthone and antifungal constituents from Monnina obtusifolia.

Three biphenyls and four xanthones have been isolated from the aerial parts of Monnina obtusifolia. The structures were established on the basis of their spectral data and that of some derivatives. The biphenyls have been isolated previously from the same genus. 1,3,6-Trihydroxy-2,5-dimethoxyxanthone is a new natural product, whereas the other xanthones have been described in other species. The antifungal activity of the isolated compounds has been determined.

Antifungal Agents↗
PubMed2002

Xanthone O-glycosides from Polygala tenuifolia.

Four xanthone O-glycosides, polygalaxanthones IV-VII were isolated from the roots of Polygala tenuifolia Willd., together with eight known compounds. The structures of the four xanthone O-glycosides were established as 6-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-1-hydroxy-3,7-dimethoxyxanthone (polygalaxanthone IV), 6-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-1,3-dihydroxy-7-methoxyxanthone (polygalaxanthone V), 6-O-(beta-D-glucopyranosyl)-1,2,3,7-tetramethoxyxanthone (polygalaxanthone VI), and 3-O-[alpha-D-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-1,6-dihydroxy-2,7-dimethoxyxanthone (polygalaxanthone VII), respectively, on the basis of analysis of spectroscopic evidence.

Glycosides↗
PubMed1998

Xanthones from the twigs of Mammea siamensis.

1,2-Dimethoxy-5-hydroxyxanthone, a new xanthone, was isolated from the twigs of Mammea siamensis, in addition to six known xanthones (5-hydroxy-1-methoxy-, 1,3-dimethoxy-5-hydroxy-, 2,5-dihydroxy-1-methoxy-, 1,7-dihydroxy-, 1,3,7-trihydroxy- and 3,5-dihydroxy-1-methoxyxanthone). Structures for these compounds were deduced from their spectral data.

Antineoplastic Agents, Phytogenic↗
PubMed2003

Identification of flavonol and xanthone glycosides from mango (Mangifera indica L. Cv. "Tommy Atkins") peels by high-performance liquid chromatography-electrospray ionization mass spectrometry.

Flavonol O- and xanthone C-glycosides were extracted from mango (Mangifera indica L. cv. "Tommy Atkins") peels and characterized by high-performance liquid chromatography-electrospray ionization mass spectrometry. Among the fourteen compounds analyzed, seven quercetin O-glycosides, one kaempferol O-glycoside, and four xanthone C-glycosides were found. On the basis of their fragmentation pattern, the latter were identified as mangiferin and isomangiferin and their respective galloyl derivatives. A flavonol hexoside with m/z 477 was tentatively identified as a rhamnetin glycoside, which to the best of our knowledge, has not yet been reported in mango peels. The results obtained in the present study confirm that peels originating from mango fruit processing are a promising source of phenolic compounds that might be recovered and used as natural antioxidants or functional food ingredients.

Chromatography, High Pressure Liquid↗
PubMed2006

Antioxidant xanthones from the pericarp of Garcinia mangostana (Mangosteen).

As part of ongoing research on cancer chemopreventive agents from botanical dietary supplements, Garcinia mangostana L. (commonly known as mangosteen) was selected for detailed study. Repeated chromatography of a CH2Cl2-soluble extract of the pericarp led to the isolation of two new highly oxygenated prenylated xanthones, 8-hydroxycudraxanthone G (1) and mangostingone [7-methoxy-2-(3-methyl-2-butenyl)-8-(3-methyl-2-oxo-3-butenyl)-1,3,6-trihydroxyxanthone, 2], together with 12 known xanthones, cudraxanthone G (3), 8-deoxygartanin (4), garcimangosone B (5), garcinone D (6), garcinone E (7), gartanin (8), 1-isomangostin (9), alpha-mangostin (10), gamma-mangostin (11), mangostinone (12), smeathxanthone A (13), and tovophyllin A (14). The structures of compounds 1 and 2 were elucidated by spectroscopic data analysis. Except for compound 2, which was isolated as a minor component, the antioxidant activities of all isolates were determined using authentic and morpholinosydnonimine-derived peroxynitrite methods, and compounds 1, 8, 10, 11, and 13 were the most active. Alpha-mangostin (10) inhibited 7,12-dimethylbenz[alpha]anthracene-induced preneoplastic lesions in a mouse mammary organ culture assay with an IC50 of 1.0 microg/mL (2.44 microM).

Antioxidants↗
PubMed1993

Design, synthesis, and pharmacological evaluation of potent xanthone dicarboxylic acid leukotriene B4 receptor antagonists.

In an effort to develop increasingly potent and specific leukotriene B4 (LTB4) receptor antagonists, several xanthone dicarboxylic acids were synthesized and evaluated. Two separate synthetic routes were used to construct a xanthone nucleus containing a regiospecific orientation of each carboxylic acid pharmacophore. These compounds represent the major conformationally-restricted analogues of benzophenone dicarboxylic acids previously shown to antagonize the activation of human neutrophils by LTB4. The most potent agent was compound 32, which inhibited the specific binding of [3H]LTB4 to receptors on intact human neutrophils (IC50, 6.2 +/- 0.1 nM), LTB4-induced luminol-dependent chemiluminescence (IC50, 55 +/- 11 nM), aggregation (IC50, 133 +/- 42 nM), and chemotaxis (IC50, 899 +/- 176 nM). The compound was a poor antagonist of N-formyl-L-methionyl-L-leucyl-L-phenylalanine-induced chemiluminescence (IC50, 1599 +/- 317 nM) and aggregation (IC50, 2166 +/- 432 nM), indicating specificity in the inhibition of LTB4-stimulated events. Compound 32 (LY210073), which was completely devoid of agonist activity, appears to be one of the strongest inhibitors of LTB4 receptor binding reported so far.

Benzophenones↗
PubMed2000

Tetrasaccharide multi-esters and xanthone glycosides from the roots of Polygala wattersii.

Ten new tetrasaccharide multi-esters, watteroses A-J (1-10), and two new xanthone glycosides, wattersiixanthones A (11) and B (12), were isolated from the roots of Polygala wattersii, together with 11 known compounds (10 oligosaccharide multi-esters and a xanthone glycoside). The structures of new compounds were elucidated on the basis of chemical and spectroscopic evidence.

China↗
PubMed2001

Xanthones from Garcinia parvifolia.

Nine new xanthones, parvixanthones A-I (1-9), isolated from the dried bark of Garcinia parvifolia, were found to have a common 1,3,6,7-oxygenated pattern for their xanthone nucleus, but various oxygenated isoprenyl or geranyl substituent groups. The structures were determined by spectroscopic methods.

Chromatography, Thin Layer↗
PubMed2003

Two new xanthone derivatives from the algicolous marine fungus Wardomyces anomalus.

A marine fungal isolate, identified as Wardomyces anomalus, was cultivated and found to produce two new xanthone derivatives, 2,3,6,8-tetrahydroxy-1-methylxanthone (1) and 2,3,4,6,8-pentahydroxy-1-methylxanthone (2), in addition to the known xanthone derivative 3,6,8-trihydroxy-1-methylxanthone (3) and the known fungal metabolite 5-(hydroxymethyl)-2-furanocarboxylic acid (4). The structures of all compounds were determined on the basis of extensive spectroscopic measurements (1D and 2D NMR, MS, UV, and IR). Compounds 1 and 4 showed significant antioxidant activities. The total extract and 1, 3, and 4 were shown to be inhibitors of p56(lck)tyrosine kinase.

Antioxidants↗
PubMed2004

Xanthones from Drimiopsis maculata.

Six new xanthones, drimiopsins A-F (1-6), have been isolated from the South African Drimiopsis maculata. The structures of these compounds were difficult to elucidate due to the lack of correlating protons seen in the NMR spectra, and INADEQUATE spectra were used to confirm the structures. Xanthones have not previously been reported from the Hyacinthaceae.

Liliaceae↗
PubMed2005

Xanthone glycosides from Polygala tenuifolia and their conformational analyses.

Seven xanthone glycosides were isolated from the cortexes of Polygala tenuifolia, and their structures were identified as polygalaxanthones VIII-XI (1-4), sibiricoxanthone B (5), 7-O-methylmangiferin (6), and lancerin (7), on the basis of spectroscopic analyses. Compounds 1-4 are new xanthone glycosides, and compounds 4 and 5 exist as rotamers. To explain this phenomenon, conformational analyses were performed on compounds 4 and 5 and other compounds with similar skeletons that were isolated from P. tenuifolia.

Glycosides↗
PubMed2006

Antiparasitic activity of some xanthones and biflavonoids from the root bark of Garcinia livingstonei.

A new biflavanoid, ent-naringeninyl-(I-3alpha,II-8)-4'-O-methylnaringenin (6), along with five known xanthones and two known biflavonoids, was isolated from the root bark of Garcinia livingstonei collected in Tanzania. The absolute configuration of 6 was established by CD spectroscopy. This compound showed moderate activity against P. falciparum (IC(50) 6.7 microM). Antitrypanosomal activity (IC(50) 0.87 microM) was observed for 1,4,5-trihydroxy-3-(3-methylbut-2-enyl)-9H-xanthen-9-one (3). The dimeric xanthone garcilivin A (4) showed a higher and nonselective antiparasitic activity and cytotoxicity (IC(50) 2.0 microM against MRC-5 cells) than its diastereoisomer garcilivin C (5) (IC(50) 52.3 microM).

Animals↗
PubMed1994

Swertifrancheside, an HIV-reverse transcriptase inhibitor and the first flavone-xanthone dimer, from Swertia franchetiana.

The first flavone-xanthone C-glucoside, swertifrancheside, was isolated from Swertia franchetiana, and its structure was elucidated on the basis of spectroscopic analysis as 1,5,8-trihydroxy-3-methoxy-7-(5',7',3'',4''- tetrahydroxy-6'-C-beta-D-glucopyranosyl-4'-oxy-8'-flavyl)-xanthone . This compound was a moderately potent inhibitor of HIV reverse transcriptase.

Antimalarials↗
PubMed1999

A new chalcone, xanthones, and a xanthonolignoid from Hypericum geminiflorum.

A new prenyl chalcone, gemichalcone C (1), was isolated from the heartwood and root of Hypericum geminiflorum. Three new xanthones-6, 7-dihyroxy-1,3-dimethoxyxanthone (2), 4-hydroxy-1, 2-dimethoxyxanthone (3), and gemixanthone A (4)-and four known xanthones were isolated from the leaves and stems of the same plant.

Carbohydrate Sequence↗
PubMed2003

A new regiospecific preparation of xanthones.

[reaction: see text] Condensation of a benzopyranonphthalide with Michael acceptors provides an efficient, general method for regiospecific preparation of xanthones as well as linear and angular polycyclic aromatic systems containing a xanthone fragment.

Benzofurans↗
PubMed2006

On the unusual fluorescence properties of xanthone in water.

Photo-excited xanthone is known to undergo ultrafast intersystem crossing (ISC) in the 1 ps time domain. Correspondingly, its fluorescence quantum yield in most solvents is very small ( approximately 10(-4)). Surprisingly, the quantum yield in water is 100 times larger, while ISC is still rapid ( approximately 1 ps), as seen by ultrafast pump probe absorption spectroscopy. Temperature dependent steady state and time resolved fluorescence experiments point to a delayed fluorescence mechanism, where the triplet (3)npi* state primarily accessed by ISC is nearly isoenergetic with the photo-excited (1)pipi* state. The delayed fluorescence of xanthone in water decays with a time constant of 700 ps, apparently by internal conversion between the (3)npi* state and the lowest lying triplet state (3)pipi*.

Luminescence↗
PubMed2000

Xanthones in cell cultures of Hypericum androsaemum.

Cell cultures of Hypericum androsaemum contain an array of prenylated xanthone aglycones and their glucosides, when grown in modified B5 medium in the dark. Derivatives of 1,3,6,7-tetrahydroxyxanthone prevail over compounds with the 1,3,5,6-oxygenation pattern. 1,7-Dihydroxyxanthone was also isolated. Xanthone accumulation parallels cell growth, is repressed by light and strongly influenced by the culture medium used.

Cells, Cultured↗