Showing papers on "Xanthone published in 2006"
171 citations
TL;DR: Changes in phenolic metabolism after elicitation with Colletotrichum gloeosporioides (CG) has been studied in Hypericum perforatum L. (HP) cell suspension cultures and the possible importance of xanthones as a component of defence mechanism of HP against biotic stress is discussed.
101 citations
TL;DR: In this article, a series of hydroxylxanthones and their derivatives were synthesized and evaluated as α-glucosidase inhibitors, aimed at clarifying the structure-activity correlation.
98 citations
TL;DR: A new prenylated xanthone, 5-O-methylcelebixanthone (1), together with six known compounds, were isolated from roots of Cratoxylum cochinchinense by spectroscopic methods and showed cytotoxic activity against the human lung cancer cell line and antimalarial activity against Plasmodium falciparum.
Abstract: A new prenylated xanthone, 5-O-methylcelebixanthone (1), together with six known compounds; celebixanthone (2), 1,3,7-trihydroxy-2,4-di(3-methylbut-2-enyl)xanthone (3), cochinchinone A (4), alpha-mangostin (5), beta-mangostin (6) and cochinchinone C (7) were isolated from roots of Cratoxylum cochinchinense. Their structures were elucidated by spectroscopic methods. Compounds 2 and 4-7 showed cytotoxic activity against the human lung cancer cell line (NCI-H187) with IC(50) values ranging from 0.65 to 5.2 microg/ml. Compounds 1, 2, 6 and 7 also showed antimalarial activity against Plasmodium falciparum with IC(50) values of 3.2, 4.9, 7.2 and 2.6 microg/ml, respectively.
76 citations
TL;DR: Mangostin, the major xanthone of Garcinia mangostana, and a series of synthetic derivatives were investigated for their in vitro antiplasmodial activity against Plasmodium falciparum; Mangostin itself showed moderate activity, but prenylated xanthones containing alkylamino functional groups exhibited quite potent antiplAsModial activity.
Abstract: Mangostin, the major xanthone of Garcinia mangostana, and a series of synthetic derivatives were investigated for their in vitro antiplasmodial activity against Plasmodium falciparum. Mangostin itself showed moderate activity, but prenylated xanthones containing alkylamino functional groups exhibited quite potent antiplasmodial activity. Some structure-activity relationships are proposed.
75 citations
TL;DR: The methanol extract and pure compounds were tested on two strains of Plasmodium falciparum, F32 ( chloroquine sensitive) and FcM29 (chloroquine resistant) and the IC50 values obtained ranged from 0.6 to 8.9 microg/ml.
Abstract: Further study of the methanol extract of the stem bark of Allanblackia monticola STANER L.C. resulted in the isolation of a new prenylated xanthenedione, designated allanxanthone C, together with the five known xanthones, garciniafuran, tovophyllin A, rubraxanthone, norcowanin and mangostin and one saponin, stigmasterol-3-O-beta-D-glucopyranoside. The structure of the new compound was established by detailed spectroscopic analysis to be 1,2-dihydro-3,6,8-trihydroxy-1,1,7-tri(3-methylbut-2-enyl)xanthen-2,9-dione (3-hydroxyapetalinone C). The methanol extract and pure compounds were tested on two strains of Plasmodium falciparum, F32 (chloroquine sensitive) and FcM29 (chloroquine resistant). The IC50 values obtained ranged from 0.6 to 8.9 microg/ml. Their cytotoxicity was estimated on human melanoma cells (A375) and the cytotoxicity/antiplasmodial ratio was found to be between 15.45 and 30.46. The antimicrobial activities against a range of microorganisms of the crude extract and some of these compounds are also reported.
75 citations
TL;DR: A xanthone derivative, named gaboxanthone (1), has been isolated from the seed shells of Symphonia globulifera and showed a potent free radical scavenging activity compared to the well-known antioxidant caffeic acid.
73 citations
TL;DR: All the crude extracts when screened for their larvicidal activities indicated very good toxicity against the larvae of Aedes aegypti.
73 citations
TL;DR: A phytochemical investigation of the constituents of the roots of Vismia laurentii has resulted in the isolation of two xanthone derivatives named laurentixanthone A and B, established by means of spectroscopic methods.
67 citations
TL;DR: The five components of S. chirata were structurally correlated and confirmed based on the fragmentation characteristics and information available in the literature, and an analytical assay was developed and validated to determine relative concentrations of mangiferin, amarogentin, isaroswerin, sweroside and swertiamarin.
Abstract: Swertia chirata is a bitter plant, used in the Indian system of medicine (Ayurveda) for various human ailments. The bioactive constituents include the xanthone and secoiridoid glycosides consisting of mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin. Methanolic extracts of S. chirata possess constituents with antidiabetic activities, which was investigated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Preliminary HPLC analyses were performed on a reversed-phase C18 column using gradient elution. In the LC/ESI-MS spectra, predominant [M+H]+ and [M+Na]+ ions were observed in positive ion mode and provided molecular mass information. The five components of S. chirata were structurally correlated and confirmed based on the fragmentation characteristics and information available in the literature. The fragmentation behavior of [M+H]+/[M+Na]+ ions of these components were deduced from the collision-induced dissociation (CID) spectra obtained from the selective on-column information-dependant acquisition (IDA) approach. Xanthone-C-glycoside showed characteristic fragment ions due to fragmentation in the C-glycosidic unit while iridoid-O-glycosides showed characteristic fragment ions due to cleavage in the glycoside linkage and retro-Diels-Alder (RDA) cleavage within an iridoid aglycone. Furthermore, on the basis of this information, an analytical assay was developed and validated to determine relative concentrations of mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin. The detection was carried out using multiple reaction monitoring (MRM) in positive ionization mode with a total analysis time of 3.5 min. The method was successfully applied to standardize four different batches of herbal preparation on the basis of relative concentration of five bioactive components.
66 citations
TL;DR: Seven known compounds and two xanthones, named cochinchinones A-D, respectively, and a synthetically known caged-prenylated xanthone, together with seven known compounds were isolated from the roots of Cratoxylum coachinchinense (Lour.) Blume.
TL;DR: DulCisxanthones C-F and dulcinone together with 22 known compounds were isolated from the flowers of Garcinia dulcis and the abilities of some of these compounds to act as radical scavengers and antibacterial agents were investigated.
TL;DR: Five benzophenones and a xanthone, isolated from Hypericum annulatum Moris, were investigated for their protective effect against carbon tetrachloride toxicity in isolated rat hepatocytes and in combination showed statistically significant protection against the toxic agent.
Abstract: Five benzophenones and a xanthone, isolated from Hypericum annulatum Moris, were investigated for their protective effect against carbon tetrachloride toxicity in isolated rat hepatocytes. The benzophenones and the xanthone gentisein were administered alone (100 microM) and in combination with CCl4 (86 microM). CCl4 undergoes dehalogenation in the liver endoplasmic reticulum. This process leads to trichlormethyl radical (*CCl3) formation, initiation of lipid peroxidation, and measurable toxic effects on the hepatocytes. The levels of thiobarbituric acid reactive substances (TBARS) were assayed as an index of lipid peroxidation (LPO). Lactate dehydrogenase (LDH) leakage, cell viability and reduced glutathione (GSH) depletion were used as signs of cytotoxicity. CCl4 significantly decreased hepatocyte viability, GSH level and increased TBARS level and LDH leakage as compared to the control. Our data indicate that 2,3',5',6-tetrahydroxy-4-methoxybenzophenone, 2-O-alpha-L-arabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone and 2-O-alpha-L-3'-acetylarabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone showed weaker toxic effects compared to CCl4 and in combination showed statistically significant protection against the toxic agent.
TL;DR: The results suggest that the reactive xanthone acetic acids are promising precursors for carbanion-mediated photocages and singlet state reactivity, which is unusual for aromatic ketones.
TL;DR: Investigation of the chemical constituents of the root bark of Artocarpus rigidus BLUME subsp.
Abstract: Investigation of the chemical constituents of the root bark of Artocarpus rigidus BLUME subsp. rigidus has led to the isolation of six, structurally diverse phenolic compounds. These included two new compounds with modified skeletons, the flavonoid 7-demethylartonol E (1) and the chromone artorigidusin (2), together with four known phenolic compounds, the xanthone artonol B (3), the flavonoid artonin F (4), the flavonoid cycloartobiloxanthone (5), and the xanthone artoindonesianin C (6). Compounds 1, 4, and 5 exhibited antiplasmodial activity against Plasmodium falciparum. All compounds showed antimycobacterial activity against Mycobacterium tuberculosis, with 4 being the most active compound (MIC 6.25 microg/ml). Compounds 5 and 6 were active against KB cells, whereas 2, 5, and 6 showed varying toxicity to BC cells. Compounds 1-3, 5, and 6 were active in the NCI-H187 cytotoxicity assay, with 3 being the most active compound (IC(50) 1.26 microg/ml).
TL;DR: The structures of GS-4, EQ-7, and -8 have been determined to be (4R,4aS, 9aR)-1,9a-dihydronidulalin A, and 9-hydroxymicroperfuranone, respectively, and the six other metabolites have been identified.
Abstract: Five metabolites tentatively called GS-1 (1)-5 (5) from Gelasinospora santi-florii, and four tentatively called EQ-4 (6), EQ-6 (7)-8 (9) together with 1-4 from Emericella quadrilineata have been isolated in a screening study on immunomodulatory fungal constituents. Among these nine metabolites, EQ-7 and 8 have been unknown. This time, the structures of GS-4 which has previously been isolated, EQ-7, and -8 have been determined to be (4R,4aS,9aR)-1,9a-dihydronidulalin A (4), (4S,4aR,9aR)-4a-carbomethoxy-1,4,4a,9a-tetrahydro-4,8-dihydroxy-6-methylxanthone (8), and 9-hydroxymicroperfuranone (9), respectively, and the six other metabolites have been identified. On bioassay, a dihydroxanthone, nidulalin A (1), a hexaketide, sordarial (5), and a xanthone, pinselin (7) have displayed significant immunosuppressive activities. The structure-activity relationships of these constituents have also been discussed.
Patent•
TL;DR: In this article, a compound comprising a xanthone or thiaxanthone sensitising moiety, capable of coordinating to a lanthanide ion by the nitrogen atom of an integral pyridyl group or a related group is described.
Abstract: The invention provides a compound comprising a xanthone or thiaxanthone sensitising moiety, capable of coordinating to a lanthanide ion by the nitrogen atom of an integral pyridyl group or a related group able to bind a lanthanide ion.
TL;DR: Two new xanthones, 1,5,6-trihydroxy-3-methoxy-4-(3-hydroxyl- 3-methylbutyl)xanthone (1) and 1,3,5-triHydroxy-6',6'-dimethyl-2H-pyrano(2',3':6,7)-2-enyl (2), have been isolated from the stems of Garcinia cowa.
Abstract: Two new xanthones, 1,5,6-trihydroxy-3-methoxy-4-(3-hydroxyl-3-methylbutyl)xanthone (1) and 1,5-dihydroxy-3-methoxy-6′,6′-dimethyl-2H-pyrano(2′,3′:6,7)-4-(3-methylbut-2-enyl)xanthone (2), have been isolated together with six known xanthones: 1,3,5-trihydroxy-6′,6′-dimethyl-2H-pyrano(2′,3′:6,7)xanthone (3), dulxanthone A (4), 1,5,6-trihydroxy-3,7-dimethoxyxanthone (5), 1,7-dihydroxyxanthone (6), 1,3,5-trihydroxy-6-methoxyxanthone (7), 1,3,6,7-tetrahydroxyxanthone (8), from the stems of Garcinia cowa (Guttiferae).
TL;DR: Two new polyprenylated xanthone epimers were isolated from gamboges of Garcinia hanburyi and exhibited significant cytotoxicities against the human leukemia K562/S and the corresponding doxorubicin‐resistant K562 /R cell lines.
Abstract: Two new polyprenylated xanthone epimers were isolated from gamboges of Garcillia hanburyi, and identified by detailed spectroscopic analysis as 30-hydroxygambogic acid (2a) and its (2S)-epimer 30-hydroxyepigambogic acid (2b). Both compounds exhibited significant cytotoxicities against the human leukemia K562/S and the corresponding doxorubicin-resistant K562/R cell lines (Table 2).
TL;DR: A new xanthone, isolated from Cratoxylum cochinchinense stems, showed free radical scavenging against DPPH and lipid peroxidation inhibition and the structure was characterized by 1D and 2D NMR techniques.
TL;DR: In this paper, an efficient and generally applicable synthesis of various [5,6]pyrano[2,3-c]pyrazol-4(1H)-ones by the reaction of either 1-substituted or 1,3disubstitized 2-pyrazolin-5-ones with different o-halopyridine carbonyl chlorides or with 3-chloroquinoline-2-carbonyl chloride, using calcium hydroxide in 1,4-dioxane, is described.
Abstract: An efficient and generally applicable synthesis of various [5,6]pyrano[2,3-c]pyrazol-4(1H)-ones by the reaction of either 1-substituted or 1,3-disubstituted 2-pyrazolin-5-ones with different o-halopyridinecarbonyl chlorides or with 3-chloroquinoline-2-carbonyl chloride, using calcium hydroxide in 1,4-dioxane, is described. In the course of the preparation of pyrazolo[4',3':5,6]pyrano[2,3-c]pyridin-4(1H)-ones, the intermediate 4-(3-chloroisonicotinoyl)-1H-pyrazol-5-ols did not cyclize spontaneously and thus were transformed into the corresponding tricycles by treatment with NaH in DMF. The N 1-unsubstituted title compounds were obtained upon treatment of the corresponding 1-(4-methoxybenzyl) protected congeners with trifluoroacetic acid.
TL;DR: Three new flavonol glycosides and a new xanthone were isolated from Polygala japonica HOUTT with eight known compounds and showed cytotoxic activity against all the five cell lines.
TL;DR: From the root bark of Securidaca longepedunculata, a heptaoxygenated xanthone has been isolated and the structure of 1 has been elucidated from 1H and 13C-NMR spectral data.
TL;DR: From aerial parts of Swertia longifolia Boiss.
TL;DR: A new tetraoxygenated xanthone, daphnifolin (1,3,5-trihydroxy-4-methoxyxanthone), along with three other xanthones, were isolated from the stem bark extracts of Mesua daphNifolia and characterized on the basis of 1D and 2D NMR spectral data.
TL;DR: Reinvestigation of the plant, Swertia decussata resulted in the isolation of four antioxidant xanthones, which were characterized as 1-hydroxy-3,7,8-trimethoxy, 1-8-dihydroxy, 3,7-dimethoxy and 1-7, 8-trihydroxy -3-methoxyxanthones.
TL;DR: Five microbial-converted compounds are new compounds that were isolated from Halenia elliptica and formed by biotransformed fungi and elucidated by spectroscopic analyses.
Abstract: 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. roseum gave 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-β-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.
Journal Article•
TL;DR: In this article, two new xanthone identified as 1,5-diliydroxy-3,6,7-triniethoxy-8-allyloxyxanthone and 1,hydroxy 3,6-diinethoxy-2-β-D-glucopyranoxanthone have been isolated from the metbanolic extract of the bark of Pinus roxburghii and the structure were established on the basis of spectroscopic data and chemical evidences.
TL;DR: Two new xanthones, 1,5,6-trihydroxy-3methoxy-4-(3-hydroxyl-3-methylbutyl)xanthone (1) and 1, 5, 6-dimethyl-2H-pyrano(2′, 3′:6,7)-4-(1, 3,methylbut-2-enyl)Xanthone(2) have been isolated from the stems of Garcinia cowa (Guttiferae) as mentioned in this paper.
Abstract: Two new xanthones, 1,5,6-trihydroxy-3-methoxy-4-(3-hydroxyl-3-methylbutyl)xanthone (1) and 1,5-dihydroxy-3-methoxy-6′,6′-dimethyl-2H-pyrano(2′,3′:6,7)-4-(3-methylbut-2-enyl)xanthone (2), have been isolated together with six known xanthones: 1,3,5-trihydroxy-6′,6′-dimethyl-2H-pyrano(2′,3′:6,7)xanthone (3), dulxanthone A (4), 1,5,6-trihydroxy-3,7-dimethoxyxanthone (5), 1,7-dihydroxyxanthone (6), 1,3,5-trihydroxy-6-methoxyxanthone (7), 1,3,6,7-tetrahydroxyxanthone (8), from the stems of Garcinia cowa (Guttiferae).
TL;DR: A new geranylated xanthone (1) was isolated from the root bark extract of Garcinia smeathmannii along with known guttiferone I, isoxanthochymol, smeathsanthones A and B, and triacontanyl caffeate as mentioned in this paper.
Abstract: A new geranylated xanthone ( 1 ) was isolated from the root bark extract of Garcinia smeathmannii Oliver along with known guttiferone I, isoxanthochymol, smeathxanthones A and B, and triacontanyl caffeate. The structures of these compounds were elucidated by spectral analysis and by comparison with the reported data. These compounds showed significant antioxidant DPPH radical scavenging activities. KEY WORDS: Garcinia smeathmanii , Xanthone, Antioxidant Bull. Chem. Soc. Ethiop. 2006 , 20(2), 247-252.