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At least 217 records · Page 12Linked to original sources
PubMed2002

Globulixanthones A and B, two new cytotoxic xanthones with isoprenoid groups from the root bark of Symphonia globulifera.

Bioassay-guided fractionation of a root bark extract of Symphonia globulifera has yielded, in addition to stigmasterol, two new xanthones with isoprenoid units, named globulixanthones A (1) and B (2). The structures of these compounds have been elucidated by spectroscopic means. They possess significant cytotoxicity in vitro against the KB cell line.

Antineoplastic Agents, Phytogenic↗
PubMed2003

Xanthones and benzophenones from the stems of Garcinia multiflora.

Two new xanthone derivatives, garcinianones A (1) and B (2), two new benzophenone derivatives, 4,6,4'-trihydroxy-2,3'-dimethoxy-3-prenylbenzophenone (3) and 4,6,3',4'-tetrahydroxy-2-methoxybenzophenone (4), and a new inseparable mixture of (1E,22Z)-1,22-diferuloyloxydocosane and (1E,24Z)-1,24-diferuloyloxyteracosane (5), together with the previously known 3,8-dihydroxy-2,4,6-trimethoxyxanthone, 6,3'-dihydroxy-2,4-dimethoxybenzophenone, maclurin (6), 2,4,6,3'-tetrahydroxybenzophenone (7), and naringenin, were isolated from the stems of Garcinia multiflora. The structures of 1-5 were elucidated by extensive analysis of their spectral data. Compounds were evaluated in the brine shrimp lethality test and in the DPPH antioxidant assay.

Animals↗
PubMed2004

Antioxidant xanthones from Garcinia vieillardii.

Two new xanthones, 6-O-methyl-2-deprenylrheediaxanthone B (1) and vieillardixanthone (2), were isolated from the stem bark of Garcinia vieillardii, as were four known compounds (4-7). The structures of 1 and 2 were determined by means of spectroscopic analysis and chemical derivatization. Each isolate was tested for its antioxidant properties based on a scavenging activity study using the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical.

Antioxidants↗
PubMed2004

Prenylated benzophenones and xanthones from Hypericum scabrum.

Two new polyprenylated benzophenones, a new polyprenylated phloroglucinol, and six new xanthone derivatives were isolated from the aerial parts of the Uzbekistan medicinal plant Hypericum scabrum. Their structures were elucidated on the basis of spectroscopic evidence. The isolated compounds showed moderate cytotoxicity for human tumor cells.

Antineoplastic Agents, Phytogenic↗
PubMed2006

Microbial O-demethylation, hydroxylation, sulfation, and ribosylation of a xanthone derivative from Halenia elliptica.

1-Hydroxy-2,3,5-trimethoxyxanthone (1), one of the major xanthone derivatives isolated from Halenia elliptica, was biotransformed by two fungi, Trichothecium roseum and Paecilomyces marquandii. Transformation of 1 by T. roseumgave 1,5-dihydroxy-2,3-dimethoxyxanthone (2), 5-O-sulfate-1-hydroxy-2,3-dimethoxyxanthone (3), 5-O-sulfate-1-hydroxy-2,3,7-trimethoxyxanthone (4), 5-O-beta-ribofuranosyl-1-hydroxy-2,3-dimethoxyxanthone (5), and 1,5,6-trihydroxy-2,3-dimethoxyxanthone (6). Compound 2 was also formed by P. marquandii. The structures of the isolated compounds were elucidated by spectroscopic analyses. Among the five microbial-converted compounds, 3, 4, 5, and 6 are new compounds.

Ascomycota↗
PubMedDate not supplied

Psorospermin, a new antileukemic xanthone from Psorospermum febrifugum.

An ethanolic extract of Psorospermum febrifugum was fractionated with antileukemic activity in vivo in the P388 lymphocytic leukemia in mice and in vitro in the KB cell culture system used as a guide. The new antileukemic xanthone psorospermin 1 was isolated, and its structure was elucidated. The chlorohydrin of O-methylpsorospermin 2 was also isolated after treatment of the fraction containing psorospermin chlorohydrin 6 with diazomethane. Psorospermin 1 was demonstrated to have significant antitumor activity in the P388 in vivo system as well as cytotoxicity against the KB in vitro system.

Animals↗
PubMedDate not supplied

New xanthones from Psorospermum febrifugum.

The isolation and structural determination of two new xanthone derivatives, 1,2,4-trimethoxy-3,8-dihydroxyxanthone, 1,2,4-trimethoxy-3-hydroxyxanthone and a known 2-methoxy-3-hydroxyxanthone from Psorospermum febrifugum var. ferrugineum are reported. The structures were elucidated by extensive analysis of 1H and 13C nmr, ms, and chemical correlations.

Hexanes↗
PubMed2006

Isolation and insecticidal/anthelmintic activity of xanthonol, a novel bis-xanthone, from a non-sporulating fungal species.

Xanthonol, a novel dimeric xanthone, was isolated from a fermentation broth of a non-sporulating fungal species using Sephadex LH20 followed by HPLC and the structure elucidated by spectral analysis. Xanthonol exhibited insecticidal and anthelmintic activities against larvae of Lucilia sericata, Aedes aegypti, and Haemonchus contortus with LD90 of 33, 8, and 50 microg/ml, respectively.

Anthelmintics↗
PubMed2002

Antiplatelet and anti-inflammatory constituents and new oxygenated xanthones from Hypericum geminiflorum.

Two new pentaoxygenated xanthones, 2,3-dihydroxy-1,6,7-trimethoxyxanthone (1) and 3,6-dihydroxy-1,5,7-trimethoxyxanthone (2) were isolated from the leaf of Hypericum geminiflorum. The antiplatelet activities of the constituents, 2,6-dimethoxy-p-benzoquinone (3), gemichalcone A (4), gemichalcone B (5), and cycloartocarpin (6), of this plant, were assessed in vitro by determining their inhibitory effects on the aggregation of washed rabbit platelets induced by various inducers. The anti-inflammatory effects of 4 and 5 were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells and neutrophils. Of the compounds tested, 4 exhibited the most potent inhibition of platelet aggregation induced by arachidonic acid (AA) and 4 and 5 strongly inhibited the release of beta-glucuronidase and lysozyme in formyl-Met-Leu-Phe (fMLP)-stimulated rat neutrophils.

Animals↗
PubMed2002

Inhibition of HIV-1 reverse transcriptase and HIV-1 replication by Calophyllum coumarins and xanthones.

As part of our continuing study on the Calophyllum species, a number of coumarins, xanthones and chromene acids from different Calophyllum species of Sri Lanka were tested for inhibitory activity against the HIV-1 and its virally-encoded reverse transcriptase (RT). These compounds were found to be inactive in both the HIV-1 RT and whole virus systems. In contrast, cordatolide A and B demonstrated IC(50) values of 19.3 and 11.7 microM, respectively, against HIV-1 replication in a novel green fluorescent protein (GFP)-based reporter cell assay (HOG.R5).

Anti-HIV Agents↗
PubMed2002

Mitochondrial destabilisation and caspase-3 activation are involved in the apoptosis of Jurkat cells induced by gaudichaudione A, a cytotoxic xanthone.

Gaudichaudione A, a cytotoxic xanthone obtained from Garcinia gaudichaudii, displayed strong growth inhibitory effects against Jurkat human leukemic cells, parental murine leukemic P388 and P388/DOX-resistant cell lines, and exhibited similar cytotoxicity against P388/DOX as well as P388, but was less toxic toward normal human Chang liver cells. A variety of apoptotic events induced by gaudichaudione A at the mitochondrial and nuclear levels has been characterized. It appears that gaudichaudione A induced a collapse of the mitochondrial transmembrane potential. Caspase-3 was activated and induced internucleosomal DNA fragmentation and externalization of PS residues. The apoptotic features were also observed in ultrastructural studies.

Animals↗
PubMed2003

The xanthones gentiacaulein and gentiakochianin are responsible for the vasodilator action of the roots of Gentiana kochiana.

Gentiana kochiana Perr. et Song. (Gentianaceae), a plant used in the traditional medicine of Tuscany (Italy) as antihypertensive remedy, exerts a vasodilator action on in vitro aortic rings that is probably linked to the blocking of the ryanodine-sensitive Ca++ channels. In the present study, three known xanthones were isolated from the crude methanolic extract of the roots: gentiacaulein, gentiakochianin, and swertiaperennin. The first two showed a vasorelaxing activity in rat aortic preparations, pre-contracted by 3 microM norepinephrine (pIC50 = 5.00 +/- 0.032 for gentiacaulein, pIC50 = 4.95 +/- 0.068 for gentiakochianin), 20 mM KCl (pIC50 = 4.90 +/- 0.15 for gentiacaulein; 4.59 +/- 0.069 for gentiakochianin), or 5 mM caffeine; on the contrary, in the same conditions, swertiaperennin did not show any vasodilator effect. In conclusion, gentiacaulein and gentiakochianin seem to be the compounds responsible for the vasorelaxing properties of the crude extract of Gentiana kochiana roots.

Animals↗
PubMed2004

Investigation of the antifungal activity of caledonixanthone E and other xanthones against Aspergillus fumigatus.

Among the different xanthones previously isolated from the stem bark of Calophyllum caledonicum, caledonixanthone E presented the strongest activity (MIC (80) = 8 microg/mL) in acidic conditions (pH 3) against the human pathogenic fungus Aspergillus fumigatus. Phase-contrast microscopy studies suggested the assembly or synthesis of cell wall components as the target of the drug. Moreover, the use of fluorescent lectins further supported an impact of caledonixanthone E on the synthesis of chitin, the major structural polysaccharide of the fungal wall. These results suggest that caledonixanthone E may be an interesting model for the design of new antifungal drugs.

Antifungal Agents↗
PubMed2004

Xanthones from Gentiana campestris as new acetylcholinesterase inhibitors.

In order to discover new acetylcholinesterase (AChE) inhibitors, different plant extracts were screened by a previously established TLC bioautographic method. The methanol extract of Gentiana campestris leaves exhibited significant inhibition of AChE activity. A bioactivity-guided fractionation approach was undertaken to isolate the active components. Four xanthones, bellidin, bellidifolin, bellidin 8-O-beta-glucopyranoside (norswertianolin), and bellidifolin 8-O-beta-glucopyranoside (swertianolin), were found to be responsible for the anti-AChE activity effects. Bellidifolin showed similar activity to galanthamine in this enzyme assay.

Acetylcholinesterase↗
PubMed2005

Xanthones from the roots of Polygala caudata and their antioxidation and vasodilatation activities in vitro.

Three new xanthones, 2-hydroxy-1,6,7-trimethoxyxanthone (1), 1,4-dimethoxy-2,3-methylenedioxyxanthone (2), and 7-hydroxy-1,2-dimethoxyxanthone (3), together with five known compounds, 2,7-dihydroxy-1-methoxyxanthone (4), 1-methoxy-2,3-methylenedioxyxanthone (5), 7-hydroxy-1-methoxyxanthone (6), euxanthone (1,7-dihydroxyxanthone) (7), and gentitein (1,3,7-trihydroxyxanthone) (8), were isolated from the roots of Polygala caudata. Their structures were established on the basis of spectral evidence. In the antioxidation activity screening in vitro with luminol chemiluminescence methods, compounds 1 - 5 and 7 and 8 showed H2O2 scavenger activity, with a scavenging effect of 58.4 - 94.5% at 10 microg/mL, and 26.0 - 84.7% at 2 microg/mL. Compounds 4 and 8 also exhibited scavenging effects on the reactive oxygen free radicals produced by macrophage respiratory bursts, with a scavenging effect of 71.7% and 63.4% at 10 microg/mL, 41.2% and 47.8% at 2 microg/mL, respectively. In the vasodilatation assay, compounds 4 - 7 exhibited relaxing activity on the contractions evoked by KCl in Wistar rat thoracic aorta rings in a dose-dependent manner.

Animals↗