Showing papers on "Xanthone published in 1999"
TL;DR: Six new sucrose esters, sibiricoses A(1)-A(6) (1-6), two new xanthone C-glycosides, sIBiricaxanthones A (7) and B (8), and a new acetophenone glycoside, s ibiricaphenone (9), were isolated from the roots of Polygala sibIRica together with six known glycosides.
Abstract: Six new sucrose esters, sibiricoses A(1)-A(6) (1-6), two new xanthone C-glycosides, sibiricaxanthones A (7) and B (8), and a new acetophenone glycoside, sibiricaphenone (9), were isolated from the roots of Polygala sibirica together with six known glycosides. The structures of new compounds were elucidated on the basis of chemical and spectroscopic evidence. The structure of the known xanthone glycoside, polygalaxanthone III (10), was revised.
63 citations
TL;DR: Two new compounds, the triterpenoid polypoda (13 E,17 E )-polypoda-7,13,17,21-tetraen-3β-ol and the xanthone E -7-geranyloxy-1,3,7-trihydroxyxanthone have been isolated from the bark of Vietnamese Cratoxylum cochinchinense.
50 citations
TL;DR: A general strategy for the preparation of substituted xanthones and embodied in the preparation (±)-O-methylsterigmatocystin (OMST) was described in this paper.
Abstract: A general strategy is described for the preparation of substituted xanthones and embodied in the preparation of (±)-O-methylsterigmatocystin (OMST), the most advanced, known intermediate in the bio...
39 citations
TL;DR: The structures of a new xanthone- O -glycoside, polycaudoside A, together with 2′-benzoylmangiferin, 1-methoxy-7-hydroxyxanthone, 1,2,8-trihydroxyXanthone and wubangziside are established on the basis of chemical studies and spectral evidence, including 2D NMR analyses.
25 citations
TL;DR: In this article, triptexanthosides A-E were isolated along with a known xanthone C-glucoside, mangiferin, from the aerial parts of Tripterospermum japonicum.
Abstract: From the aerial parts of Tripterospermum japonicum, five new xanthone glycosides, named triptexanthosides A-E, were isolated along with a known xanthone C-glucoside, mangiferin. Their structures were elucidated as 1, 2, 6, 8-tetrahydroxyxanthone (norswetianin) 1-O-β-D-glucopyranoside and 1-O-β-gentiobioside, and 1, 2, 8-trihydroxy-5, 6-dimethoxyxanthone 2-O-β-D-glucopyranoside, 2-O-β-primeveroside and 1-O-gentiobioside, respectively, from spectroscopic evidence and acid hydrolysis.
24 citations
TL;DR: Two new xanthone glycosides have been isolated from cell suspension cultures of Hypericum patulum and their structures were elucidated by spectral techniques.
Abstract: Two new xanthone glycosides, patuloside A (3-beta-D-glucopyranosyloxy-1,5,6-trihydroxy-9H-xanthene-9-one, 1) and patuloside B [3-(2-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl)oxy-1,5, 6-trihydroxy-9H-xanthene-9-one, 2], have been isolated from cell suspension cultures of Hypericum patulum. Their structures were elucidated by spectral techniques.
23 citations
TL;DR: In vitro results are consistent with the view that the active principles present in P.cyparissias antagonise, in a non competitive but, reversible manner the contractions induced by chemical inflammatory mediators in the guinea pig trachea in vitro, and might explain at least in part, the medicinal use of this plant in the management of inflammation, asthma and allergy.
Abstract: Objective: This study describes the in vitro action of the hydroalcoholic extract and the 1,7-dihydroxy-2,3-dimethoxy xanthone isolated from P. cyparissias on agonist and ovalbumin induced contractions in trachea, from normal and actively sensitised guinea pigs.¶Results: The hydroalcoholic extract of P. cyparissias (0.125 to 1mg/ml), incubated with the guinea-pig trachea for 20 min, had no effect on the resting tone of the preparations, but caused a concentration-dependent, reversible and non competitive inhibition of contractions induced by acetylcholine, histamine, compound 48/80, bradykinin, substance P, prostaglandin E2 and the stable analogue of thromboxane A2 mimetic U 46619. The calculated mean IC50 values for the hydroalcoholic extract were: 0.37, 0.51, 0.06, 0.32, 0.48, 0.3 and 0.17 mg/ml, respectively. Also, the extract of P. cyparissias (0.125 to 0.5 mg/ml) antagonised, in a graded manner (IC50 of 0.46mg/ml) ovalbumin-induced contractions in guinea-pig trachea obtained from animals which had been actively sensitised to this antigen. Pre-incubation of the preparations with the purifed xanthone isolated from P. cyparssias (2.5 to 80 μg/ml; 10.0 to 310.0 μM) caused significant and concentration-dependent, reversible and non-competitive inhibition of the contractile responses elicited by acetylcholine, histamine, bradykinin, substance P, U 46619 and prostaglandin E2. The calculated mean IC50 values for these effects were: 132.0, 73.0, 9.2, 32.0, 110.6 and 66.0 μM, respectively. At very high concentrations (155.0-620.0 μM) the xanthone also antagonised contraction induced by KCl in guinea-pig trachea (IC50 of 190.0 μM).¶Conclusions: Taken together these and our previous in vivo results are consistent with the view that the active principles present in P.cyparissias, including the 1,7-dihydroxy-2,3-dimethoxy xanthone, antagonise, in a non competitive but, reversible manner the contractions induced by chemical inflammatory mediators in the guinea pig trachea in vitro. Thus, these results might explain at least in part, the medicinal use of this plant in the management of inflammation, asthma and allergy.
22 citations
TL;DR: In this paper, a new xanthone glycoside was isolated together with mangiferin from Davallia solida and the structures were elucidated by chemical and spectral means.
15 citations
Journal Article•
TL;DR: The effects of twelve aminoalkanolic derivatives of xanthone on platelet aggregation have been evaluated and the most active compound was R-(+)-2-N-(7-chloro-2-xanthonemethyl)- 2-N-methylamino-1-butanol [IV], which nearly completely inhibited the aggregation concentration (TAC) of thrombin.
Abstract: The effects of twelve aminoalkanolic derivatives of xanthone on platelet aggregation have been evaluated. Five from them inhibited thrombin-induced platelet aggregation. The most active compound was R-(+)-2-N-(7-chloro-2-xanthonemethyl)-2-N-methylamino-1-butanol [IV] which, at a concentration of 40 micrograms/ml, nearly completely inhibited the aggregation concentration (TAC) of thrombin.
14 citations
13 citations
TL;DR: A new xanthone (1) was isolated together with nine known xanthones (2 - 10, 12) and a known benzofuran (11) from the stems of Garcinia kola Heckel (Guttiferae) collected in Nigeria and their structures were characterized on the basis of spectroscopic and chemical evidence.
Abstract: A new xanthone (1) was isolated together with nine known xanthones (2 - 10, 12) and a known benzofuran (11) from the stems of Garcinia kola Heckel (Guttiferae) collected in Nigeria and their structures were characterized on the basis of spectroscopic and chemical evidence.
TL;DR: In this paper, the authors studied the chemical composition of 12 species of Gentianaceae and extracted 17 xanthone glycosides, nine of them were new natural products and one was a new natural product.
Abstract: Most species of Gentianaceae in Qinghai-Tibet Plateau are traditional Tibetan medicines which were used for stabilizing liver functions and improving the gallbladder. They were used for curing hepatitis, cholecystitis and other diseases. We have studied the chemical composition of 12 species of Gentianaceae and extracted 17 xanthone glycosides. Nine of them are new natural products. Pharmacological studies showed that xanthone C-glycosides is beneficial to the gallbladder and that xanthone O-glycosides is the effective component in curing hepatitis.
TL;DR: One prenylated xanthone, ananixanthone as discussed by the authors, was isolated from the bark of Symphonia globulifera and determined by NMR spectroscopy including 2D techniques.
Abstract: One new prenylated xanthone, ananixanthone, was isolated from the bark of Symphonia globulifera The structure was determined by NMR spectroscopy including 2D techniques.
TL;DR: A novel antifungal agent, Sch 56036 (1 ), was isolated from the fermentation culture broth of an Actinoplanes sp Structure elucidation of 1 was accomplished by the analysis of spectroscopic data Compound 1 was identified as a new polycyclic xanthone as mentioned in this paper.
Abstract: A novel antifungal agent, Sch 56036 ( 1 ), was isolated from the fermentation culture broth of an Actinoplanes sp Structure elucidation of 1 was accomplished by the analysis of spectroscopic data Compound 1 was identified as a new polycyclic xanthone Biological evaluation of 1 indicated that the compound possesses broad spectrum antifungal activity against various yeasts and dermatophytes with geometric mean MIC values ranging from 0017∼0031 μg/mL, respectively
01 Sep 1999
TL;DR: In this paper, a new xanthone glycoside was isolated as described in Experimental Section, mp 270 °C. It analysed for C2sH360'6 and on hydrolysis with 7% H2S04 gave galactose and glucose (PC) as sugar moieties and an aglycone which was shown to be a Xanthone by its colour reactions and UV spectral data.
Abstract: The rhizome of Acarus calamus Linn. (Fam. Araceae), commonly known as "Butch" is a useful medicinal plant found throughout India, Ceylon and Sikkim. In India it is mostly found in marshy tracts of Kashmir and Sirmon in Manipur, and Nagahills t. Its rhizome has medicinal properties against bed bugs, moths, lice, emetic stomach in dyspep etc? The new xanthone glycoside was isolated as described in Experimental Section, mp 270 °C. It analysed for C2sH360'6 and on hydrolysis with 7% H2S04 gave galactose and glucose (PC) as sugar moieties and an aglycone which was shown to be a xanthone by its colour reactions and UV spectral data.
TL;DR: Alkanolamines derivatives of xanthone, synthesized by of the reaction of an appropriate aminoalcohol with corresponding 2-bromomethylxanthones, displayed anti MES activity with a protective index in the range 2.21-5.84 corresponding with that for phenytoin, carbamazepine and valproate.
Abstract: Synthesis and physicochemical properties of alkanolamine derivatives of xanthone are described. Alkanolamines were synthesized by of the reaction of an appropriate aminoalcohol with corresponding 2-bromomethylxanthones. The obtained compounds 1-13 were evaluated for anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole seizure threshold (scMet) assays and for neurotoxicity (TOX). Several alkanolamines were found to be active in both the anticonvulsant tests. Most interesting were the 2-amino-1-propanol-, 1-amino-2-propanol- or 1-amino-2-butanol derivatives of 6-methoxy- or 6-chloroxanthone, which displayed anti MES activity with a protective index (TD50/ED50) in the range 2.21-5.84 corresponding with that for phenytoin, carbamazepine and valproate.
TL;DR: A general strategy for the preparation of substituted xanthones and embodied in the preparation (±)-O-methylsterigmatocystin (OMST) was described in this article.
Abstract: A general strategy is described for the preparation of substituted xanthones and embodied in the preparation of (±)-O-methylsterigmatocystin (OMST), the most advanced, known intermediate in the bio...
TL;DR: In this article, a new xanthone was identified from the chloroform and ethyl acetate fractions of Halenia corniculata (Gentianaceae).
Abstract: A new xanthone, a new xanthone glycoside and a known xanthone have been isolated from the chloroform and ethyl acetate fractions of Halenia corniculata (Gentianaceae). They were identified as 1,3-dihydroxy-2,4,5,7-tetramethoxyxanthone, 1-hydroxy-2,7-dimethoxy-3-O-β-D-glucopyranosylxanthone and 1,2,3-trihydroxy-5-methoxyxanthone. 1,3-Dihydroxy-2,4,5,7-tetramethoxyxanthon is a revised structure from 1,6-dihydroxy-2,3,4,8-tetramethoxyxanthone reported by our previous paper.