Showing papers on "Xanthone published in 2012"
TL;DR: In this article, the authors describe the xanthones as "privileged structures" and describe methods for the construction of the (polysubstituted) unsaturated xanthone core.
Abstract: Many fungi, lichens, and bacteria produce xanthones (derivatives of 9H-xanthen-9-one, “xanthone” from the Greek “xanthos”, for “yellow”) as secondary metabolites. Xanthones are typically polysubstituted and occur as either fully aromatized, dihydro-, tetrahydro-, or, more rarely, hexahydro-derivatives. This family of compounds appeals to medicinal chemists because of their pronounced biological activity within a notably broad spectrum of disease states, a result of their interaction with a correspondingly diverse range of target biomolecules. This has led to the description of xanthones as “privileged structures”.(1) Historically, the total synthesis of the natural products has mostly been limited to fully aromatized targets. Syntheses of the more challenging partially saturated xanthones have less frequently been reported, although the development in recent times of novel and reliable methods for the construction of the (polysubstituted) unsaturated xanthone core holds promise for future endeavors. In particular, the fascinating structural and biological properties of xanthone dimers and heterodimers may excite the synthetic or natural product chemist.
310 citations
Journal Article•
TL;DR: The fascinating structural and biological properties of xanthone dimers and heterodimers may excite the synthetic or natural product chemist.
Abstract: Many fungi, lichens, and bacteria produce xanthones (derivatives of 9H-xanthen-9-one, “xanthone” from the Greek “xanthos”, for “yellow”) as secondary metabolites. Xanthones are typically polysubstituted and occur as either fully aromatized, dihydro-, tetrahydro-, or, more rarely, hexahydro-derivatives. This family of compounds appeals to medicinal chemists because of their pronounced biological activity within a notably broad spectrum of disease states, a result of their interaction with a correspondingly diverse range of target biomolecules. This has led to the description of xanthones as “privileged structures”.(1) Historically, the total synthesis of the natural products has mostly been limited to fully aromatized targets. Syntheses of the more challenging partially saturated xanthones have less frequently been reported, although the development in recent times of novel and reliable methods for the construction of the (polysubstituted) unsaturated xanthone core holds promise for future endeavors. In particular, the fascinating structural and biological properties of xanthone dimers and heterodimers may excite the synthetic or natural product chemist.
236 citations
TL;DR: In this paper, α-mangostin (α-M), a polyphenolic xanthone derivative from mangosteen, concentration-dependently attenuated the neurotoxicity induced by Aβ-(1-40) or Aβ(1-42) oligomers (EC(50) = 3.89 nM, 4.14 nM respectively).
109 citations
TL;DR: A concise and straightforward strategy to construct a xanthone skeleton via an intramolecular cross-dehydrogenative coupling (CDC) of 2-aryloxybenzaldehydes has been developed and can tolerate various functional groups.
106 citations
TL;DR: Five xanthones, 1,4,5,6-tetrahydroxyxanthone (1) and bracteaxanthones III-VI (2-5) together with twenty-six known compounds, isolated from the ethanol extract of the stem bark of Garcinia bractEata, were elucidated via spectroscopic analyses and a preliminary structure-activity relationship is discussed.
72 citations
TL;DR: In this paper, the xanthone profile and content of mangosteen pericarp, aril segments and a functional beverage made from whole mangosteens were compared.
62 citations
TL;DR: Subsequent conversion by the short-chain dehydrogenase/reductase (SDR) MdpC into the corresponding 3-hydroxy-3,4-dihydroanthracen-1(2H)-one implies that deoxygenation is the first step in monodictyphenone biosynthesis.
Abstract: Reduction of emodin by sodium dithionite resulted in the formation of two tautomeric forms of emodin hydroquinone. Subsequent conversion by the short-chain dehydrogenase/reductase (SDR) MdpC into the corresponding 3-hydroxy-3,4-dihydroanthracen-1(2H)-one implies that deoxygenation is the first step in monodictyphenone biosynthesis. Implications for chrysophanol formation as well as reaction sequences in the related xanthone, ergochrome, and bianthraquinone biosyntheses are discussed.
55 citations
TL;DR: Known coniothranthraquinone 1 and emodin displayed strong antibacterial activity against methicillin-resistant Staphylococcus aureus with the MIC values of 8 and 4 μg/mL, respectively.
Abstract: Trichodermaquinone (1) and trichodermaxanthone (2) were isolated from the marine-derived fungus Trichoderma aureoviride PSU-F95 together with eleven known compounds. The structures were interpreted by spectroscopic methods. Known coniothranthraquinone 1 and emodin displayed strong antibacterial activity against methicillin-resistant Staphylococcus aureus with the MIC values of 8 and 4 μg/mL, respectively.
51 citations
TL;DR: Four new diphenyl ethers, pestalotethers A–D, three new chromones, pest alochromones A–C, and one new butenolide, pestAlolide (9), together with 11 known compounds were isolated from the mangrove-derived fungus Pestalotiopsis sp.
48 citations
TL;DR: A new pathway is presented that provides a full rationale for the results of the gene deletion studies and reconciles them with previous biosynthetic results, and is in accord with established chemical and biosynthetics mechanisms.
Abstract: Biosynthetic genes for the prenylated xanthone shamixanthone have been identified in the Aspergillus nidulans genome; based on assignment of putative functions from sequence analyses and selected gene deletions, a pathway was proposed leading from the anthraquinone emodin via the benzophenone carboxylic acid monodictyphenone and the xanthone emericellin to shamixanthone. Several aspects of this proposed pathway are inconsistent with previously identified biosynthetic intermediates: the anthraquinone chrysophanol and the benzophenone aldehyde derivatives arugosins F and A/B, isotopic labelling studies and chemical precedents. A new pathway is presented that provides a full rationale for the results of the gene deletion studies and reconciles them with previous biosynthetic results, and is in accord with established chemical and biosynthetic mechanisms. The importance of interpreting genetic information in terms of established biosynthetic events is discussed.
45 citations
TL;DR: Results show that gaudichaudione H has the strongest apoptosis-inducing effect and cell growth inhibition effect among these xanthones and it may have the potential to be developed into a new anticancer agent.
TL;DR: One new xanthone, caroxanthone together with six known xanthones, 4-prenyl-2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone (2), smeathxanthones A ( 3 ), gartanin ( 4 ), euxanthone( 5 ), 8-hydroxycudraxanthone G ( 6 ) and morusignin I ( 7 ) were isolated from the stem bark of Garcinia nob
TL;DR: The cDNA of a benzophenone synthase (BPS) was cloned and the recombinant protein expressed from the fruit pericarps of Garcinia mangostana L., which contains mainly prenylated xanthones, showed an amino acid sequence identity with other plant BPSs belonging to the same family (Clusiaceae).
TL;DR: In this paper, the authors used response surface methodology (RSM) to determine the optimal conditions for the total xanthone yield and the influence of parameters were determined by Box-Behnken design.
Abstract: Mangosteen fruit pericarp is one of the important sources of bioactive compound xanthone. Supercritical carbon dioxide (SC-CO2) extraction was employed to extract xanthones from mangosteen fruit pericarp at three different levels of pressure (200–300 bar), temperature (40–60 °C) and solvent to material ratio (100–300 kg/kg). The optimal conditions for the total xanthone yield and the influence of parameters were determined by response surface methodology (RSM) using Box–Behnken design. In our study, the increase in total xanthone yield in SC-CO2 fluid extraction depends more on the solute’s vapor effect. From response surface plots, pressure, temperature and solvent to material ratio exhibited independent and interactive effects on the extraction of xanthones. A regression equation for predicting the total xanthone yield was derived by statistical analysis, and a model with predictive ability of 0.99 was obtained. Maximum xanthone yield of 8.01% was predicted by RSM at 60 °C, 300 bar and a solvent to material ratio of 300 kg/kg while experimentally a yield of 7.56% was achieved. HPLC analysis was carried out for the optimum conditions for the identification and quantification of the xanthones. The antioxidant activities of the extracts were investigated by ferric reducing antioxidant power (FRAP) and the results showed that the extracts were enriched with antioxidant compound.
TL;DR: Nine known compounds were investigated for their ability to inhibit low-density lipoprotein (LDL) oxidation and platelet aggregation in human whole blood in vitro and most of the compounds showed strong antioxidant activity with compound 8 showing the highest inhibition with an IC₅₀ value of 0.5 μM.
TL;DR: The mechanism, by which the three chiral xanthone derivatives cause conduction blockade in the rat sciatic nerve and their ability to prevent hypotonic haemolysis, given that erythrocytes are non-excitable cells devoid of voltage-gated Na(+) channels, are described.
TL;DR: Two new xanthone–anthraquinone heterodimers have been isolated from an extract of an unidentified fungus by bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi.
Abstract: Two new xanthone-anthraquinone heterodimers, acremoxanthone C (5) and acremoxanthone D (2), have been isolated from an extract of an unidentified fungus of the order Hypocreales (MSX 17022) by bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Two known related compounds, acremonidin A (4) and acremonidin C (3) were also isolated, as was a known benzophenone, moniliphenone (1). The structures of these isolates were determined via extensive use of spectroscopic and spectrometric tools in conjunction with comparisons to the literature. All compounds (1-5) were evaluated against a suite of biological assays, including those for cytotoxicity, inhibition of the 20S proteasome, mitochondrial transmembrane potential and nuclear factor-κB.
TL;DR: Xanthone has potent anticancer activity not only on sensitive but also on doxorubicin resistant cancer cell lines and mPEG-b-p(HPMAm-Lac(2)) micelles are therefore attractive delivery systems of xanthone for the treatment of cancer.
TL;DR: The results suggest that alpha-mangostin is able to modulate GPx activity as a potential antioxidant strategy, thereby transiently consuming GSH levels.
Abstract: BackgroundIn a previous report, we have characterized the antiperoxidative properties of alpha-mangostin in different toxic models tested in nerve tissue preparations.ObjectivesHere, the modulatory effects of this xanthone on the glutathione system (reduced glutathione (GSH) levels, glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities) were tested in synaptosomal P2 fractions isolated from rat brains in order to provide further information on key mechanisms exerted by this antioxidant in the nervous system.MethodsSynaptosomes were exposed to increasing concentrations of the xanthone, and also challenged to the toxic actions of a free radical generator, ferrous sulfate (FeSO4). For comparative purposes, the mitochondrial toxin 3-nitropropionic acid (3-NP) was also explored.ResultsAlpha-mangostin significantly decreased the levels of GSH, and increased GPx activity.DiscussionThis finding was interpreted as a modulatory action of the GSH system in preparation to exert antioxid...
TL;DR: The purification of the acetone extract from the inflorescences of Garcinia cowa led to the isolation of a new benzophenone derivative, cowanone, together with seven known xanthones, including α-mangostin, which were evaluated for their antibacterial activities against Staphylococcus aureus and methicillin-resistant S. aUREus.
Abstract: The purification of the acetone extract from the inflorescences of Garcinia cowa led to the isolation of a new benzophenone derivative, cowanone (1), together with seven known xanthones, α-mangostin (2), β-mangostin (3), cowanin (4), fuscaxanthone A (5), 9-hydroxycalabaxanthone (6), garcinianone A (7) and cowanol (8). The structures of the isolated compounds were elucidated by analysis of their spectroscopic data including 1D and 2D NMR data. All isolated compounds were evaluated for their antibacterial activities against Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA).
TL;DR: A new polyprenylated xanthone (9H-xanthen-9-one) and a new poly prenyl-ated benzophenone (6) were isolated from the bark of Garcinia oblongifolia, together with five known compounds including the four xanthones 3-5 and 7 and a benzphenone 6.
Abstract: A new polyprenylated xanthone (=9H-xanthen-9-one) and a new polyprenylated benzophenone, namely oblongifolixanthone A (1) and garciniagifolone A (2), were isolated from the bark of Garcinia oblongifolia, together with five known compounds including the four xanthones 3–5 and 7 and a benzophenone 6. The structures of 1 and 2 were established by detailed analysis of their spectroscopic data, especially 1D- and 2D-NMR spectra and HR-ESI-MS data. All these compounds were assayed for their cytotoxic activities against three human tumor cell lines (HeLa, SGC7901, and HepG2). The 1,3,6,7-tetrahydroxy-9H-xanthen-9-one (3) was inactive, and the other compounds showed weak to moderate activity.
TL;DR: In this paper, two highly oxygenated xanthones, named muchimangins E ( 1 ) and F ( 2 ), have been isolated from the root of Securidaca longepedunculata (Polygalaceae), and their structures were elucidated by analyses of spectral data to be a novel xanthone with a diphenylmethyl substituent at C-2.
TL;DR: The selectivity index calculated from the affinity to the double-stranded and loop regions suggested that the N,N-dimethyl derivative of X2S would be suitable for the screening of small molecules binding to RRE, and Titration experiments suggested that thioxanthone derivatives showed a more prominent tendency of multiple binding to RNA than xanth one derivatives.
Abstract: A series of xanthone and thioxanthone derivatives with aminoalkoxy substituents were synthesized as fluorescent indicators for a displacement assay in the study of small-molecule-RNA interactions. The RNA-binding properties of these molecules were investigated in terms of the improved binding selectivity to the loop region in the RNA secondary structure relative to 2,7-bis(2-aminoethoxy)xanthone (X2S) by fluorimetric titration and displacement assay. An 11-mer double-stranded RNA and a hairpin RNA mimicking the stem loop IIB of Rev response element (RRE) RNA of HIV-1 mRNA were used. The X2S derivatives with longer aminoalkyl substituents showed a higher affinity to the double-stranded RNA than the parent molecule. Introduction of a methyl group on the aminoethoxy moiety of X2S effectively modulated the selectivity to the RNA secondary structure. Methyl group substitution at the C1' position suppressed the binding to the loop regions. Substitution with two methyl groups on the amino nitrogen atom resulted in reducing the affinity to the double-stranded region by a factor of 40%. The effect of methyl substitution on the amino nitrogen atom was also observed for a thioxanthone derivative. Titration experiments, however, suggested that thioxanthone derivatives showed a more prominent tendency of multiple binding to RNA than xanthone derivatives. The selectivity index calculated from the affinity to the double-stranded and loop regions suggested that the N,N-dimethyl derivative of X2S would be suitable for the screening of small molecules binding to RRE.
TL;DR: Three new xanthones and six known compounds isolated from the resin of Garcinia hanburyi showed high inhibitory effects on the cell lines and were tested for their cytotoxicities against A549, HCT116, SK-BR-3 and HepG2.
TL;DR: In this paper, two new polyisoprenylated acylphloroglucinols, thoreliones A and B, and a new tetracyclic xanthone, oxy-thorelione A, together with twelve known compounds, were isolated from the bark of Calophyllum thorelsii using spectroscopic methods and chemical modification.
TL;DR: A novel and unexpected yeast-catalyzed oxidation that has selectively given a new oxy-guttiferone A and norathyriol is found.
TL;DR: Investigations of the constituents of the stem barks of Garcinia xanthochymus have yielded two new compounds, garcinenones X and Y, along with five known xanthones, and the cell growth inhibitory activity of the isolated compounds against the PC-3 cell line was measured.
Abstract: Investigations of the constituents of the stem barks of Garcinia xanthochymus have yielded two new compounds, garcinenones X (1) and Y (2), along with five known xanthones, 1,4,5,6-tetrahydroxy-7-(3-methylbut-2-enyl)xanthone (3), 1,4,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (4), 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (5), 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methylbut-2-enyl)xanthone (6), and 1,5,6-trihydroxy-7,8-di(3-methylbut-2-enyl)-6',6'dimethylpyrano(2',3':3,4)xanthone (7). The structures of the compounds were determined by spectroscopic methods. The cell growth inhibitory activity of the isolated compounds against the PC-3 cell line was measured. Among them, compounds 2, 3, 5, and 6 exhibited significant inhibitory effects with IG50 values of 14.3, 15.5, 11.1, and 6.8 microM, respectively.
Journal Article•
TL;DR: A benzophenone, 2,2',5,6'-tetrahydroxybenzophenone (1), and one xanthone, 5-hydroxy-3methoxyxanthone (2), were newly described as natural products from the leaves and the stem barks of Hypericum lanceolatum.
Abstract: A benzophenone, 2,2’,5,6’-tetrahydroxybenzophenone (1), and one xanthone, 5-hydroxy-3methoxyxanthone (2), were newly described as natural products from the leaves and the stem barks of Hypericum lanceolatum, along with the known compounds friedelin (3), betulinic acid (4), allanxanthone A (5), 1,3,6-trihydroxyxanthone (6), isogarcinol (7), sitosterol 3-O-β-D-glucopyranoside (8), 1-hydroxy-6methoxyxanthone (9), 6,7-dihydroxy-1,3-dimethoxyxanthone (10), 3-hydroxy-5-methoxyxanthone (11), 1,7dihydroxy-3,6-dimethoxyxanthone (12) and calophyllumin A (13). Their structures were elucidated by spectroscopic means and comparison with published data.
TL;DR: A positive correlation between xanthone accumulation and antifungal activity has been shown and Xanthone production increased 2.7 times following the three-step method.
TL;DR: The continuing studies on secondary metabolites from the stem bark of Calophyllum soulattri has led to the isolation of another new diprenylated xanthone, phylattrin (1), in addition to five other xanthones and two common sterols.
Abstract: Our continuing studies on secondary metabolites from the stem bark of Calophyllum soulattri has led to the isolation of another new diprenylated xanthone, phylattrin (1), in addition to five other xanthones and two common sterols. The xanthones are soulattrin (2), caloxanthone C (3), macluraxanthone (4), brasixanthone B (5) and trapezifolixanthone (6) while the sterols are stigmasterol (7) and β-sitosterol (8). The structures of these compounds were determined on the basis of spectroscopic analyses such as 1D and 2D-NMR, HRESIMS, IR and UV. Compounds 1-7 exhibited moderate cytotoxic activities against SNU-1, HeLa, Hep G2, NCI-H23, K562, Raji, LS174T, IMR-32 and SK-MEL-28 cells.