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PubMed2003

Prenylated xanthones with NGF-potentiating activity from Garcinia xanthochymus.

Two prenylated xanthones, 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (1) and 1,2,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (2), were isolated from the wood of Garcinia xanthochymus along with a known xanthone, 12b-hydroxy-des-D-garcigerrin A (3). Their structures were elucidated by spectroscopic analysis. Compound 1 (10 muM), 2 (10-30 muM) and 3 (10 muM) showed a markedly enchancing activity of nerve growth factor (NGF)-mediated neurite outgrowth on PC12D cells.

Animals↗
PubMed2001

Inhibitory effects of xanthones on platelet activating factor receptor binding in vitro.

Nine naturally occurring xanthones were investigated for their platelet activating factor (PAF) receptor binding inhibitory effects using rabbit platelets. 2-(3-methylbut-2-enyl)-1,3,5-trihydoxyxanthone, macluraxanthone, 1,3,5-trihydroxy-6,6'-dimethylpyrano(2',3':6,7)-4-(1,1-dimethylprop-2-enyl)xanthone, 6-deoxyjacareubin and 2-(3-methylbut-2-enyl)-1,3,5,6-terahydroxyxanthone showed strong inhibition with IC50 values of 4.8, 11.0, 21.0, 29.0 and 44.0 microM, respectively. The prenyl group at C-2, the dimethylprop-2-enyl group at C-4 and the hydroxyl group at C-5 are all beneficial to the binding of xanthones to the PAF receptor. The results revealed that xanthones can represent a new class of natural PAF receptor antagonists.

Animals↗
PubMed2001

A new class of nonsteroidal aromatase inhibitors: design and synthesis of chromone and xanthone derivatives and inhibition of the P450 enzymes aromatase and 17 alpha-hydroxylase/C17,20-lyase.

Aromatase (P450arom) is a target of pharmacological interest for the treatment of breast cancer. In this paper, we report the design, synthesis, and in vitro biological evaluation of a series of new (di)benzopyranone-based inhibitors of this enzyme. The design of the new compounds was guided by a CoMFA model previously developed for a series of nonsteroidal aromatase inhibitors. Both the chromone and the xanthone nuclei were taken as molecular skeletons, and the functions supposed to be critical for binding to the aromatase active site - a heterocyclic ring (imidazole or 1,3,4-triazole) linked to the aromatic moiety by a methylene unit and an H-bond accepting function (CN, NO(2), Br) located on the aromatic ring at a suitable distance from the heterocyclic nitrogen carrying the lone pair--were attached to them. The chromone, xanthone, and flavone derivatives were prepared by conventional synthetic methods from the appropriate methyl analogues. Aromatase inhibitory activities were determined by the method of Thompson and Siiteri, using human placental microsomes and [1 beta,2 beta-(3)H]testosterone as the labeled substrate. All the compounds were also tested on 17 alpha-hydroxylase/C17,20-lyase (P450 17), an enzyme of therapeutic interest for the treatment of prostatic diseases. The goal to find new potent inhibitors of aromatase was reached with the xanthone derivatives 22d,e (IC(50) values 43 and 40 nM, respectively), which exceeded the potency of the known reference drug fadrozole and also showed high selectivity with respect to P450 17. Moreover, compounds 22g-i based on the same xanthonic nucleus showed fairly high potency as P450 17 inhibitors (IC(50) values 220, 130, and 42 nM, respectively). Thus, they might be new leads for the development of drug candidates for androgen-dependent diseases.

Aromatase Inhibitors↗
PubMed2005

Xanthone and sesquiterpene derivatives from the fruits of Garcinia scortechinii.

The fruits of Garcinia scortechinii afforded 10 new compounds: four caged-tetraprenylated xanthones (scortechinones Q-T, 1-4), four rearranged xanthones (scortechinones U-X, 5-8), and two sesquiterpene derivatives (scortechterpenes A, B, 9, 10), together with 14 known compounds: one sesquiterpene, two biflavonoids, and 11 caged-polyprenylated xanthones. Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously. All xanthone derivatives were evaluated for antibacterial activity against methicillin-resistant Staphylococcus aureus.

Anti-Bacterial Agents↗
PubMed2005

Antibacterial caged-tetraprenylated xanthones from the stem bark of Garcinia scortechinii.

Five new caged-tetraprenylated xanthones, scortechinones L - P (1-5), together with six known scortechinones (A, B, D, F, I and J) and one known xanthone, 4 '',5 ''-dihydro-1,5-dihydroxy-6 ',6 '-dimethylpyrano(2 ',3 ':6,7)-4 '',4 '',5 ''-trimethylfurano(2 '',3 '':3,4)- xanthone, were isolated from the crude methanol extract of the stem bark of Garcinia scortechinii. The structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously. The antibacterial activity of all caged-polyprenylated xanthones, isolated from the latex and stem bark of G. scortechinii, was evaluated. Scortechinone B (6) exhibited significant antibacterial activity against a methicillin-resistant Staphylococcus aureus strain with an MIC value of 2 microg/mL. From the MIC values, some structure-antibacterial activity relationships were established.

Anti-Bacterial Agents↗
PubMed2006

Xanthones from Garcinia mangostana (Guttiferae).

Studies on the stem of Garcinia mangostana have led to the isolation of one new xanthone mangosharin (1) (2,6-dihydroxy-8-methoxy-5-(3-methylbut-2-enyl)-xanthone) and six other prenylated xanthones, alpha-mangostin (2), beta-mangostin (3), garcinone D (4), 1,6-dihydroxy-3,7-dimethoxy-2-(3-methylbut-2-enyl)-xanthone (5), mangostanol (6) and 5,9-dihydroxy-8- methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyrano-[3,2-b]-xanthene-6-one (7). The structures of these compounds were determined by spectroscopic methods such as 1H NMR, 13C NMR, mass spectrometry (MS) and by comparison with previous studies. All the crude extracts when screened for their larvicidal activities indicated very good toxicity against the larvae of Aedes aegypti. This article reports the isolation and identification of the above compounds as well as bioassay data for the crude extracts. These bioassay data have not been reported before.

Aedes↗
PubMed2003

Capillary electrophoretic behaviors of pharmacologically active xanthones from Securidaca inappendiculata with beta-cyclodextrin as a buffer additive.

The capillary electrophoretic (CE) behaviors of ten xanthones in the presence of beta-cyclodextrin (CD) are investigated, and apparent analyte-selector binding constants between beta-CD and the xanthones in the CE running buffer are calculated to elucidate the migration order. Also, the separation selectivity with beta-CD additive is compared with that of sulfated beta-CD additive. It is indicated that beta-CD can greatly change the separation selectivity of xanthones, and the electrophoretic behaviors of xanthones are rather different when using beta-CD from that when using sulfated beta-CD as an additive.

Buffers↗
PubMed2005

Xanthone derivatives: new insights in biological activities.

Xanthones or xanthen-9H-ones (dibenzo-gamma-pirone) comprise an important class of oxygenated heterocycles whose role is well-known in Medicinal Chemistry. The biological activities of this class of compounds are associated with their tricyclic scaffold but vary depending on the nature and/or position of the different substituents. In this review, an array of biological/pharmacological effects is presented for both natural and synthetic xanthone derivatives, with an emphasis on some significant studies on structure-activity relationships. The antitumor activity of some xanthones as well as the related targets, particularly PKC modulation studies, is also discussed in detail. Examples of the "hit" compounds involved in cancer therapy, namely DMXAA, psorospermin, mangiferin, norathyriol, mangostins, and AH6809, a prostanoid receptor antagonist, are also mentioned. Finally, a historical perspective of these xanthonic derivatives, their relevance as therapeutic agents and/or their uses as pharmacological tools and as extract components in folk medicine are also highlighted.

Xanthones↗
PubMed2000

Xanthones as antimalarial agents: stage specificity.

The erythrocytic development of Plasmodium falciparum is divided into the ring, trophozoite, and schizont stages based on morphologic assessment. Using highly synchronous ring and trophozoite cultures of P. falciparum, we observed considerable differences in their sensitivity to hydroxyxanthones: trophozoites were much more sensitive to the drugs than ring-stage parasites. Trophozoites treated with a prototypic xanthone, the 2,3,4,5,6-pentahydroxy derivative (X5), were arrested in their development and became degenerate in appearance within 24 hr of drug exposure. These morphologic changes appeared to reflect the cytotoxic nature of the action of the drug against the parasite, since daughter ring-stage forms were not observed following addition of the drug. That X5 was more active against parasites in the later stages of intraerythrocytic development is consistent with the proposed mode of action, inhibition of heme polymerization. Knowledge of the structure-activity relationships for xanthones as antimalarial agents has also been expanded. Xanthones with a hydroxyl group in the peri-position exhibited decreased antimalarial activity, possibly due to intramolecular hydrogen bonding with the carbonyl and consequent reduced affinity for heme. Paired hydroxyls attached to the lower half of the xanthone greatly enhanced drug potency.

Animals↗
PubMed2004

[Determination of xanthones in Swertia mussotii and Swertia franchetiana by high performance liquid chromatography].

A simple and rapid method for simultaneous separation and determination of xanthones in Swertia mussotii and Swertia franchetiana by high performance liquid chromatography has been established. The analysis was performed on a Kromasil C18 column (250 mm x 4.60 mm i.d., 5 microm) (at 20 degrees C) eluted with methanol and 0.1% aqueous phosphoric acid (73: 27 in volume ratio) as mobile phase at a flow rate of 1.0 mL/min and with UV detection at 260 nm. Results showed that xanthones were separated successfully from each other and from other interfering components. There was a good linear relationship between the content of component and its peak area for each xanthone, with the correlation coefficients of 0.999 2 - 0.999 9. The convenient method can be used for quantitative analysis of xanthones.

Chromatography, High Pressure Liquid↗
PubMed1977

Phytochemical investigation of xanthones of Eustoma grandiflorum (Raf.) Shinners.

Six polyoxygenated xanthones were isolated from the roots of Eustoma grandiflorum (Raf.) Shinners collected in Texas. Structural elucidation of five of these xanthones (1-hydroxy-3,7-dimethoxyxanthone, 1-hydroxy-3,5-dimethoxyxanthone, 1-hydroxy-3,5,6,7-tetramethoxyxanthone, 1-hydroxy-3,5,6,7,8-pentamethoxyxanthone, and 1-hydroxy-3,7,8-trimethoxyxanthone) was accomplished via UV, IR, NMR, and mass spectrometry; traditional physical-chemical methods; or direct comparison with a prepared derivative. The sixth xanthone derivative was characterized incompletely. The pentamethoxyxanthone is a new compound and has been designated generically as eustomin. The probable occurrence of these six xanthone compounds in the plant as glycosides is reported.

Chemical Phenomena↗
PubMed2003

Chemical constituents of Garcinia fusca: structure elucidation of eight new xanthones and their cancer chemopreventive activity.

We describe the isolation and spectrometric structure elucidation of eight new xanthones, fuscaxanthone A (1), B (2), C (3), D (4), E (5), F (6), G (7), and H (8), together with eight known xanthones from the stem bark of Garcinia fusca collected in Thailand. All the new xanthones were shown to have a terpenoid (prenyl and/or geranyl) side chain(s) in their molecules. We also present the results of a primary screening of the inhibitory effects of eight xanthones (9-16) isolated as major components of this plant on 12-O-tetradecanoylphorbol-13-acetate induced Epstein-Barr virus early antigen activation in Raji cells.

Antigens, Viral↗
PubMed2003

Antibacterial xanthones from Kielmeyera variabilis mart. (Clusiaceae).

The bioassay-guided fractionation of stems from Kielmeyera variabilis, traditionally used in Brazilian folk medicine, yielded assiguxanthone-B (1), kielcorin (4), 2,5-dihydroxybenzoic acid (3), and a mixture of xanthones containing assiguxanthone-B (1) and 1,3,5,6-tetrahydroxy-2-prenylxanthone (2) (1:1 w/w). The xanthone mixture inhibited Staphylococcus aureus and Bacillus subtilis at a concentration of 6.25 g/ml. When tested alone, the minimal inhibitory concentration of assiguxanthone-B was 25 g/ml against B. subtilis. Kielcorin and 2,5-dihydroxybenzoic acid were inactive against both strains. None of the fractions was active against Escherichia coli or Pseudomonas aeruginosa. Viable cells of S. aureus were reduced by a 1-3 log CFU/ml within 12 h after exposure of one to eight times the MIC of the xanthone mixture. It is not known whether the tetrahydroxy-2-prenylxanthone or other components of the xanthone mixture are responsible for the main antibacterial activity or whether additive or synergistic action is involved

Anti-Bacterial Agents↗
PubMed1975

Chemical constituents of gentianaceae XIV: tetraoxygenated and pentaoxygenated xanthones of Swertia purpurascens Wall.

The whole plant of Swertia purpurascens Wall. (Gentianaceae) has been shown to contain five tetraoxygenated and three pentaoxygenated zanthones. These are identified as 1,5,8-trihydroxy-3-methoxyxanthone, 1,3,8-trihydroxy-5-methoxyzanthone, 1-hydroxy-3,7,8-trimethoxyxanthone, 1,3,7,8-tetrahydroxyxanthone, 1,3,5,8-tetrahydroxyxanthone, and 1-hydroxy-3,4,7,8-tetramethoxyxanthone by chemical and spectral evidence. Additionally, the crude mixture of natural xanthones has been shown to include two partially emthylated pentaoxygenated xanthones as minor entities, which yield 1-hydroxy-3,4,7,8-tetramethoxyxanthone and 1-hydroxy-3,4,5,8-tetramethoxyxanthone on methylation. This is the first time that pentaoxygenated xanthones have been found in a member of the genus Swertia. 1-Hydroxy-3,4,7,8-tetramethoxyxanthone was previously known only as a synthetic compound. The total xanthones of S. purpurascens produce significant CNS stimulant actions, consistent with some therapeutic uses of the plant extract in the Indian system of medicine. The chemotaxonomic significance of the cooccurrence of various biogenetically related chemical characters in a single plant species is appraised.

Amphetamine↗
PubMedDate not supplied

[Comparative choleretic properties of natural xanthone compounds from Gentianopsis barbata].

Comparative data are presented for the choleretic activity of xanthones isolated from Gentianopsis barbata (Froel.) Ma. (Gentianaceae family): a sum of xanthone glycosides (I) and aglycons (II); xanthone aglycons, including decussatin [1-(OH)-3,7,8-(OCH3)3] (III) and gentiacaulein [1,7-(OH)-3,8-(OCH3)2] (IV); and xanthone glycoside gentiabavaroside [1-O-primverosyl-7-(OH)-3,8-(OCH3)2] (V). It was established that (II) is superior to (I) with respect to cholagogic effect and is inferior to (III) and (IV) with respect to cholatostimulant action.

Animals↗
PubMed2005

Synthesis, and cytotoxic and antiplatelet activities of oxime- and methyloxime-containing flavone, isoflavone, and xanthone derivatives.

A series of oxime- and methyloxime-containing flavone, isoflavone, and xanthone derivatives (1-12) were synthesized (Scheme) and evaluated for their cytotoxic (Table 1) and antiplatelet activities (Table 2). The in vitro anticancer assay indicated that the cytotoxicity of structurally related compounds decreases in the order isoflavones (7a-7c) > flavones (8a-8c) > xanthones (9a-9c), electron-releasing substituents (R) on the Ph ring being favorable (mean GI50 values of 2.84, 12.3, and 20.9 microM for 7c, 8c, and 9c, resp.). The inhibition of platelet aggregation induced by arachidonic acid (AA) similarly decreased from the isoflavone 1 (IC50 = 2.97 microM) to the flavone 2 (7.70 microM) to the xanthone 3 (inactive). Thereby, compound 1 seems to be a promising lead, since it was not only the most-potent aggregation inhibitor (IC50 = 2.97 microM), but was also found to be noncytotoxic at a concentration of 100 microM.

Antineoplastic Agents↗
PubMed2005

Syntheses, structures, photoluminescence and theoretical studies of xanthone in crystalline resorcinarene-based inclusion complexes.

Two new crystalline resorcinarene-based xanthone inclusion complexes, CECRxanthoneMeOH (1), and HECR2 xanthone6 MeOH (2) (CECR = C-ethylcalix[4]resorcinarene, HECR = hexaethylresorcin[6]arene) have been prepared to study the relation between photophysical properties and solid-state structure. Compared with the neat crystals, the xanthone phosphorescence is severely quenched in both solids, but the lifetime is an order of magnitude larger in 2, in which xanthone occurs as a dimer, than in 1, in which it occurs as a monomer. The electronic transitions involved in the photoluminescent process, and the relation between the energy levels of host and guest and emission quenching of the guest in the supramolecular solid have been investigated by means of time-dependent density functional theory (TDDFT) calculations.

Calixarenes↗
PubMed2006

Synthesis of new xanthone analogues and their biological activity test--cytotoxicity, topoisomerase II inhibition, and DNA cross-linking study.

In this report, we prepared some 3-(2',3'-epoxypropoxy)xanthones and their epoxide ring opened halohydrin analogues, and evaluated their cytotoxicity and topoisomerase II inhibition activity using doxorubicin and etoposide as references, respectively. Another xanthone compound 9, 1,3-di(2',3'-epoxypropoxy)xanthone, was also synthesized and its DNA cross-linking property including other two biological activities investigated. The biological test results showed compound 9 possessed excellent cytotoxic and topoisomerase II inhibitory activity than other compounds tested. It also exhibited significant DNA cross-linking activities.

Antineoplastic Agents↗