The Glucosides from Swertia mussotii Franch

Swertia mussotii Franch. is a herb used for treatment of liver disease in Qinghai-Tibcran Plateau folk. Further investigation on chemical constituents in aqueous extract of Swertia mussotii Franch. has been reported here. Seven compounds (Ⅰ, Ⅲ–Ⅷ) were achieved except mangiferin (Ⅱ) isolated previously by a chromatograph. They belong in secoiridoids, flavonoids and xanthonoids, respectively. The structures of known compounds were identified as amarogentin(Ⅲ), swertisin(Ⅷ), 8-O-β-D-glucopyranosyl-1, 3, 5-trihydroxyxanthone(Ⅶ) and 8-O-β-D-glucopyranosyl-(1-6)-β-D-glucopyranosyl)-I, 7-dihydroxy-3-methoxyxanthone (Ⅵ). The structures of other three new compounds have been elucidated as 7-O-β-D-xylopy-ranosyl-1, 8-dihydroxy-3-methoxyxanthone (Ⅳ), 7-O-[α-L-rhamnopyranosyl- (1-2)-β-D-xylopyranosyl]-l,8-dihydroxy-3-methoxyxanthone(Ⅰ)and 3-O-β-D-glucopyranosy 1,8-dihydroxy-5-methoxyxanthone (Ⅴ), by means of the chemical and spectral methods. Mangiferin, amarogentin and 7-0- [α-L-rhamnopyranosyl-(1-2)-β-D-xylopyranosyl]-l,8-dihydroxy-3-methoxyxanthone are the principal glucosides in this plant.     

The Chemical Constituents of Swertia przewalskii Pissjauk.

Seven xanthonenoid compounds and a triterpenic acid have been isolated from Swertia przewalskii Pissjauk. Their structures were identified as 1,8-dihydroxy-3,7-dimethoxyxarthone(Ⅰ), 1,7-dihydroxy-3,8-dimethoxyxanthone (Ⅱ), oleanolic acid (Ⅲ), l-hydroxy-3,7,8-trimethoxyxanthone (Ⅳ), 1,7,8-trihydroxy-3-methoxyxanthone (Ⅴ), 8-0-[β-D-xylopyranosyl-(l--6)-β-D-glucopyranosyl]- 1,7-dihydr0xy- 3-methoxyxanthone (Ⅵ), 1-O- [β-D-xylopyranosyl-(1-6)-β-D-glucopyranosyl]-7,8-dihydroxy- 3-methoxyxanthone (Ⅶ) and 1-O- [β-D-xylopyranosyl-(1-6)-β-D-glucopyranosyl]-8-hydroxy-3,7-dimethoxyanthone (Ⅷ) respectively, by means of chemical and spectral methods or comparing with the authentic samples directly.     

Isolation and Identification of the Xanthone Constituents from Swertia mussotii Franch

Swertia mussotii Fraeh (Family Gentianaceae) is a herb used as medicine for liver diseases in Tibetan. Its principal antihepatitisic constituents, oleanolic acid and mangiferin, have been reported. The present paper reports eight xanthones obtained from this plant. Their structures have been identified as 1,8-dihydroxy-3,5-dimethoxyxanthone Ⅰ, 1-hydroxy-3,5-dimethoxyxanthone Ⅱ, 1-hydroxy-3,7,8-trimethoxyxanthone Ⅲ, 8-hydroxy- 1,3,5-trimethoxyxanthone Ⅳ, 1,8-dihydroxy-3,7-dimethoxyxanthone Ⅴ, 1,7,8-trihydroxy- 3-methoxyxanthone Ⅵ, 1,7-dihydroxy-3,4,8-trimethoxyxanthone Ⅶ, and 1,3,8-trihydro- xy-5-methoxyxanthone Ⅷ. Of them, 1,7-dihydroxy-3,4,8-trimethoxyxanthone is a new natural product.     

Polyanxanthone A, B and C, three xanthones from the wood trunk of Garcinia polyantha Oliv

Three xanthones, polyanxanthone A (1), B (2) and C (3) have been isolated from the methanol extract of the wood trunk of Garcinia polyantha, along with five known xanthones: 1,3,5-trihydroxyxanthone (4); 1,5-dihydroxyxanthone (5); 1,3,6,7-tetrahydroxyxanthone (6); 1,6-dihydroxy-5-methoxyxanthone (7) and 1,3,5,6-tetrahydroxyxanthone (8). Their structures were determined by means of 1D- and 2D-NMR techniques. Some of the above compounds were screened for their anticholinesterase activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes.     

The Xanthones of Swertia erythtrosticta Maxim

Swertia erythrosticta Maxim. (Gentianaceae) is a herb used for curing some diseases in Tibetan traditional medicine system. Eight xanthones were isolated from this species. Their structures were identified as 1,8-dihydroxy-3,7-dimethoxyxanthone(Ⅰ), 1,5,8-trihydroxy-3-methoxyxanthone (Ⅱ), 1,3,8-trihydroxy-5-methoxyxanthone (Ⅲ), 1,7,8-trihydroxy-3-methoxyxanthone (Ⅳ), 1,3,5,8-tetrahydroxyxanthone (Ⅴ), 1,3,7,8-tetrahydroxyxanthone(Ⅵ), as well as 8-O-β-D-glucopyranosyl-1, 5-dihydroxy-3 -metho xy xanthone(Ⅶ), 8-O-β-D-gl ucopyr anosyl- 1,3,5- trihydroxyxanthone(Ⅷ) by means of chemical methodes and spectral analyses.     

Xanthones from Tovomita Excelsa

The trunk wood of Tovomita excelsa (Guttiferae) from north-eastern Brazil contains, besides betulinic acid, 1,5-dihydroxy-6-methoxyxanthone, 1,6-dihydroxy-5-methoxyxanthone, 5,6-dihydroxy-1-methoxyxanthone and 1,7- dihydroxy-6-methoxyxanthone.     

Study on Chemical Constituents of Gentianopsis barbata var. Stennocalyx H. W. Li ex T.N. Ho

Nine compounds were isolated from Gentianopsis barbata var. stennocalyx H. W. Li ex. T.N.Ho. Their structures are identified as 1-hydroxy4, 7, 8-trimethoxyxanthone (Ⅰ), 1, 7-dihydroxy-3, 8-dimethoxyxanthone (Ⅱ), 1, 7, 8-trihydroxy-3-methoxyxanthone (Ⅲ), 1-O-(β-D- xylopyranosyl-(1→6)-β-D-glucopyranosyl)-3, 7, 8-trimethoxyxanthone (Ⅳ), 1-O-(β-D-xylopy- ranosyl- (1→6)-β-D-glucopyranosyl)-7-hydroxy-3, 8-dimethoxyxanthone (Ⅴ), 1-O-(β-D-xylo- pyranosyl-(1→6)-β-D-glucopyranosyl)-7, 8-dihydroxy-3-methoxyxanthone (Ⅵ), luteolin-7-O- β-D-glucoside (Ⅶ), oleanolic acid (Ⅷ) and ursolic acid (Ⅸ) by means of chemical methods and UV, IR and NMR determinations respectively.     

Chemical constituents of Polygala tenuifolia roots and their inhibitory activity on lipopolysaccharide-induced nitric oxide production in BV2 microglia

A methanolic extract of the roots of Polygala tenuifolia (Polygalaceae) significantly attenuated nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated BV2 microglia cells. Five xanthones, 1-hydroxy-7-methoxyxanthone (1), 3,6-dihydroxy-1,2,7-trimethoxyxanthone (2), 1,3,6-trihydroxy-2,7-dimethoxyxanthone (3), 1,7-dihydroxy-2,3-dimethoxyxanthone (4) and 1,7-dihydroxy-3-methoxyxanthone (5), and five phenylpropanoids, 4-hydroxy-3-methoxypropiophenone (6), methyl 4-hydroxy-3-methoxycinnamic acid (7), 3,4,5-trimethoxycinnamic acid (8), 4-methoxycinnamic acid (9) and β-d-(3-O-sinapoyl) fructofuranosyl-α-d-(6-O-sinapoyl)glucopyranoside (10), were isolated from CHCl(3) fraction using bioactivity-guided fractionation. Among these compounds, compounds 1, 2, 4, 5 and 7 showed significant inhibitory effects on LPS-induced NO production in BV2 microglia cells at the concentration ranging from 10.0 to 100.0 μM.     

Xanthones from Lawsonia inermis

Two new xanthones isolated from Lawsonia inermis have been characterised as 1, 3-dihydroxy-6, 7-dimethoxyxanthone and 1-hydroxy-3, 6-diacetoxy-7-methoxyxanthone and named laxanthone-I and II, respectively.     

Xanthones as inhibitors of microsomal lipid peroxidation and TNF-alpha induced ICAM-1 expression on human umbilical vein endothelial cells (HUVECs)

Xanthones bearing different functionalities, namely 1-hydroxyxanthone (1), 3-hydroxyxanthone (2), 1,4-dihydroxyxanthone (3), 2,6-dihydroxyxanthone (4), 1,2-diacetoxyxanthone (5), 2,6-diacetoxyxanthone (6), 3-methoxyxanthone (7), 1,3,7-trimethoxyxanthone (8) and 1,5-dihydroxy-6-methoxyxanthone (9) were synthesised and examined for their effect on nicotinamide adenine dinucleotide phosphate (NADPH)-catalysed liver microsomal lipid peroxidation and on tumour necrosis factor-alpha (TNF-alpha) induced expression of intercellular adhesion moledule-1 (ICAM-1) on endothelial cells, with a view to establish structure-activity relationship. Hydroxy- and acetoxyxanthones showed potent inhibitory effects on NADPH-catalysed lipid peroxidation and TNF-alpha induced expression of ICAM-1 on endothelial cells.     

Xanthones from Hypericum chinense

Six xanthones, 1,3,7-trihydroxy-2-(2-hydroxy-3-methyl-3-butenyl)-xanthone (1), 1,7-dihydroxy-2,3-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-xanthone (2), 1,3,7-trihydroxy-5-methoxyxanthone (3), 1,7-dihydroxy-5,6-dimethoxyxanthone (4), 4,5-dihydroxy-2,3-dimethoxyxanthone (5), 1,3-dihydroxy-2,4-dimethoxyxanthone (6) and 21 known xanthones were isolated from the leaves and stems of Hypericum chinense. Their structures were established based on spectroscopic studies.     

Study on the Chemical Constituents of Comastoma pulmonarium (Turcz.) Toyohuni

Eight compounds were isolated from Comastoma pulmonarium (Gentianaceae). Theirstructures are identified as1,8-dihydroxy-3,5-dimethoxyxanthone(Ⅰ),1,8-dihydroxy-3,7-dimetho-xyxanthone(Ⅱ), 1-hydroxy-3,7,8-trimethoxyxanthone(Ⅲ),8-hydroxy-l,3,5-trimethoxyxanthone(Ⅳ), 1,3,8-trihydroxy-7-methoxyxanthone(Ⅴ), 1-O-β-D-glucopyranosyl-3,8-dihydroxy-7-methxy-xanthone(Ⅵ), oleanolic acid(Ⅶ) and swertisin(Ⅷ) by means of chemical methods andUV, IR, NMR and MS respectively. The compound Ⅵ is a new natural product. It wasnamed as comastomaside.     

Xanthones and flavonoids from Leiothrix curvifolia and Leiothrix flavescens

8-Carboxymethyl-1,6-dihydroxy-3,5-dimethoxyxanthone, 8-carboxymethyl-1,5,6-trihydroxy-3-methoxyxanthone and 8-carboxymethyl-1,3,5,6-tetrahydroxyxanthone were isolated from the capitula of Leiothrix curvifolia and Leiothrix flavescens and characterized by spectroscopic methods, mainly 1D and 2D NMR experiments, as well as by electrospray mass spectrometry. Eight known flavonoids were also isolated and they were identified by 1D and 2D NMR experiments and comparison with literature data.     

Chemical constituents from Gentianella turkestanorum (Gentianaceae)

Phytochemical investigation of Gentianella turkestanorum (Gentianaceae) afforded nineteen compounds, including six xanthones (1–6), two triterpenoids (7–8), eight flavones (9–16) and three iridoids (17–19). Here, we firstly reported that 1-hydroxy-3,5-dimethoxyxanthone (4), 1, 8-dihydroxy-3-methoxyxanthone (5), apigenin (9), quercetin (10), luteolin-7-O-glucoside (12) and three other compounds (1, 8-dihydroxy-3-methoxyxanthone (5), apigenin-7-O-gluco (1″ → 3‴) glucoside (15) and luteolin-7-O-gluco (1″ → 3‴) glucoside (16)) could be isolated from G. turkestanorum. The occurrence of chemical data and the sequence data might be employed as common constituents of the genera Gentianella, Lomatogonium and Swertia.     

Xanthones from Calophyllum teysmannii var. inophylloide

Further study of the wood of Calophyllum teysmannii Miq. var. inophylloide yielded xanthones 7-hydroxy-1,2,8-trimethoxyxanthone, 6-hydroxy-1,2,5-trimethoxyxanthone, and 2-carbomethoxy-6-methoxyxanthone in addition to 3,8-dihydroxy-1,2,4-trimethoxyxanthone, 3-hydroxy-2,4-dimethoxyxanthone, 1,7-dihydroxy-3-methoxyanthone (gentisin) and 2-hydroxyxanthone.     

Production of xanthones with free radical scavenging properties, emodin and sclerotiorin by the cultured lichen mycobionts of Pyrenula japonica

From the cultures of the spore-derived mycobionts of the lichen Pyrenula japonica, two new xanthones, 1,8-dihydroxy-3-hydroxymethyl-5-methoxyxanthone and 1,2,8-trihydroxy-5-methoxy-3-methylxanthone, were isolated along with 1,7-dihydroxy-3-methylxanthone, 1,5,8-trihydroxy-3-methylxanthone, 1,8-dihydroxy-5-methoxy-3-methylxanthone, emodin and sclerotiorin. Their structures were determined by spectroscopic methods. Sclerotiorin was isolated for the first time from lichen mycobionts. Radical scavenging activities of the isolated xanthones were also studied.     

A new chromanone acid from the bark of Calophyllum dryobalanoides

A new chromanone acid, calodryobalanoic acid, along with six known compounds, apetalic acid, isoblancoic acid, lupeol, 1-hydroxy-2-methoxyxanthone, 1,7-dihydroxy-3-methoxyxanthone, and 5,7,4′-trihydroxyflavanone, was isolated from the bark of Calophyllum dryobalanoides collected in Vietnam. The structure of the new compound was elucidated using mainly 1-D and 2-D NMR techniques (¹H and ¹³C NMR, HSQC, HMBC, COSY, and NOESY) and IR spectroscopy. The stereochemistry was determined on the basis of NMR results and DFT calculations.     

Xanthones from Swertia punctata

Isolation of 1-O-primeverosyl-3,8-dihydroxy-5-methoxyxanthone and 1-O-gentiobiosyl-3,7-dimethoxy-8-hydroxyxanthone, along with five known xanthones, isobellidifolin, methylbellidifolin, isoswertianin, methylswertianin and norswertianin-1-O-beta-D-glucoside, from the roots of Swertia punctata is reported. In the aerial parts four xanthones, bellidifolin, methylbellidifolin, swertianolin and mangiferin, and flavone-C-glucoside, isoorientin were identified. The chemotaxonomic and pharmacological significance of these results is discussed.     

Xanthone O-glycosides from Polygala tenuifolia

Four xanthone O-glycosides, polygalaxanthones IV-VII were isolated from the roots of Polygala tenuifolia Willd., together with eight known compounds. The structures of the four xanthone O-glycosides were established as 6-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-1-hydroxy-3,7-dimethoxyxanthone (polygalaxanthone IV), 6-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-1,3-dihydroxy-7-methoxyxanthone (polygalaxanthone V), 6-O-(beta-D-glucopyranosyl)-1,2,3,7-tetramethoxyxanthone (polygalaxanthone VI), and 3-O-[alpha-D-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-1,6-dihydroxy-2,7-dimethoxyxanthone (polygalaxanthone VII), respectively, on the basis of analysis of spectroscopic evidence.     

Two benzophenone O-arabinosides and a chromone from Hypericum annulatum

Two benzophenone O-arabinosides, annulatophenonoside (1) and acetylannulatophenonoside (2) were isolated from the methanol extract of the herb of Hypericum annulatum. The structures of the benzophenones were established as 2-O-alpha-L-arabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone (1) and 2-O-alpha-L-3"-acetylarabinofuranosyl-3',5',6-trihydroxy-4-methoxybenzophenone (2) based on spectral and chemical evidence. A chromone, 5,7-dihydroxy-3-methylchromone (3) was isolated from the chloroform extract. Although it has been previously synthesized it is encountered in a plant source for the first time. Co-occurrence of the two new benzophenone O-arabinosides along with the biogenetically related 1,5,7-trihydroxy-3-methoxyxanthone was not found.