Showing papers on "Xanthone published in 1982"
TL;DR: In this article, the 13C nuclear magnetic resonance chemical shifts of aryl carbons in these C-glucosylxanthones (2-5) were assigned.
Abstract: Four C-glucosylxanthones [Mangiferin (3), isomangiferin (2), 4 and 5] and three C-glucosylflavones [swertisin (6), isoswertisin (7) and isoswertiajaponin (8)] were isolated from the fresh leaves of Iris florentina L. (Iridaceae). The structures of 4 and 5 were shown to be 7-O-methylmangiferin and 7-O-methylisomangiferin, respectively, by chemical and spectroscopic methods. In addition, the 13C nuclear magnetic resonance chemical shifts of aryl carbons in these C-glucosylxanthones (2-5) were assigned. On the basis of the co-occurrence of several types of xanthone and flavone C-glucosides, the biosynthetic relationship between both C-glucosides is briefly discussed.
54 citations
TL;DR: A new xanthone glucoside named isoswertianolin (2) was isolated from Swertia japonica and its structure was elucidated to be 5-O-β-glucopyranoside of bellidifolin by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy.
Abstract: A new xanthone glucoside named isoswertianolin (2) was isolated from Swertia japonica and its structure was elucidated to be 5-O-β-glucopyranoside of bellidifolin by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. In connection with this study, the structure of swertianolin (1), a constituent of this plant, was reinvestigated by NMR spectroscopy, leading to the revision of its structure (the location of its glucosyl linkage) from 1-O-β-glucopyranoside of bellidifolin (3) to 8-O-β-glucopyranoside of 3. It follows that 1 is identical with the glucoside isolated from Gentiana campestris by Kaldas et al. in 1974. Analogously, the structure of norswertianolin (6), previously isolated from Swertia randaiensis HAYATA, was also revised, being formulated as 8-O-β-glucopyranoside of desmethylbellidifolin (7).
33 citations
TL;DR: Oleanolic acid, mangiferin, and two new xanthone glucosides, named lanceoside and lancerin, were isolated from the aerial parts of Tripterospermum lanceolatum.
27 citations
TL;DR: Oleanolic acid, norathyriol, and a new xanthone glycoside, tripteroside, which was characterized as N 6 O -β-d -glucoside were isolated from the fresh herb Tripterospermum taiwanense as mentioned in this paper.
24 citations
TL;DR: The bark of Calophyllum calaba var calaba contains a new xanthone, 2,8-di-(3-methylbut-2-enyl)-1,3-dihydroxy-7-methoxyxanthone (calocalabaxanthone) as discussed by the authors.
21 citations
TL;DR: The stem bark of Garcinia quadrifaria has yielded the novel xanthone 1, 3, 5-trihydroxy-4, 8-di(3, 3dimethylallyl)xanthone and the biflavonoids O-methylfukugetin and morelloflavone.
18 citations
TL;DR: The RM values of a series of xanthone derivaties obtained in a chromatographic system were correlated with the calculated log P values, indicating the importance of lipophilic character in determining the acute toxicity of xAnthone derivatives in mice.
14 citations
13 citations
13 citations
TL;DR: In this paper, the xanthone 1,8-dihydroxy-2,3,4,6-tetramethoxy-9H-xanthone3 was isolated and characterized from Centaurium cachanlahuen.
Abstract: From the plantCentaurium cachanlahuen, swertiaperenine1, swercherine2, decusatine4, oleanolic acid5 and the xanthone 1,8-dihydroxy-2,3,4,6-tetramethoxy-9H-xanthone3 were isolated and characterized
8 citations
Journal Article•
TL;DR: By appropriate superimposing of fenofibrate and fen ofibric acid molecules, two xanthone derivatives (closed models) may be obtained and very promising for further studies is the chlorine-free 3-isomer (3e).
Abstract: By appropriate superimposing of fenofibrate and fenofibric acid molecules, two xanthone derivatives (closed models) may be obtained. These compounds as well as their four chlorine-free isomers were prepared and tested on adrenaline- and theophylline-induced lipolysis in rat fat cells in comparison with ethyl 2-(4-chlorophenoxy)-2-methylpropionate (clofibrate). Some of these new derivatives besides being good inhibitors of adrenaline effect, as clofibrate is, were also very active in reducing theophylline-induced lipolysis. Very promising for further studies is the chlorine-free 3-isomer (3e). The possible difference in the action mechanism of these compounds as compared with clofibrate and the structure-activity relationships are briefly discussed.
TL;DR: The depside-like esters 3a and 3b underwent a Smiles rearrangement on treatment with base as discussed by the authors, and the resulting diphenyl ethers 4a and 4b were converted into the xanthonecarboxylic acids 6a and 6b which are not readily accessible by other routes.
TL;DR: In this article, the datiscanin (datiscetin 3-rutinoside) was isolated from the herbage of Datisca cannabina L, and the structure of 2′,3,5,7,tetrahydroxyflavone 3-0-β-D-glucopyranoside has been established for it.
Abstract: The new flavonoid glycoside datiscanin has been isolated from the herbage ofDatisca cannabina L., and the structure of 2′,3,5,7-tetrahydroxyflavone 3-0-β-D-glucopyranoside has been established for it. After datiscin (datiscetin 3-rutinoside), this is the second datiscetin glycoside found in nature.
TL;DR: In this paper, the 13C NMR spectra of 1, 3, 6-trihydroxy-7methoxy-8-(3, 7-dimethyl-2, 6 octadienyl)xanthone and its dimethyl derivative are discussed.