Showing papers on "Xanthone published in 2001"

Phomoxanthones A and B, novel xanthone dimers from the endophytic fungus Phomopsis species.

Abstract: Phomoxanthones A (1) and B (2), two novel xanthone dimers, were isolated from the endophytic fungus Phomopsis sp. BCC 1323. Structures of 1 and 2 were elucidated by spectroscopic methods. These compounds exhibited significant in vitro antimalarial and antitubercular activities and cytotoxicity.

A New Class of Nonsteroidal Aromatase Inhibitors: Design and Synthesis of Chromone and Xanthone Derivatives and Inhibition of the P450 Enzymes Aromatase and 17α-Hydroxylase/C17,20-Lyase

Abstract: Aromatase (P450arom) is a target of pharmacological interest for the treatment of breast cancer. In this paper, we report the design, synthesis, and in vitro biological evaluation of a series of new (di)benzopyranone-based inhibitors of this enzyme. The design of the new compounds was guided by a CoMFA model previously developed for a series of nonsteroidal aromatase inhibitors. Both the chromone and the xanthone nuclei were taken as molecular skeletons, and the functions supposed to be critical for binding to the aromatase active site − a heterocyclic ring (imidazole or 1,3,4-triazole) linked to the aromatic moiety by a methylene unit and an H-bond accepting function (CN, NO2, Br) located on the aromatic ring at a suitable distance from the heterocyclic nitrogen carrying the lone pair − were attached to them. The chromone, xanthone, and flavone derivatives were prepared by conventional synthetic methods from the appropriate methyl analogues. Aromatase inhibitory activities were determined by the method o...

Cinnamic acid is a precursor of benzoic acids in cell cultures of Hypericum androsaemum L. but not in cell cultures of Centaurium erythraea RAFN.

Abstract: Benzoic acids are precursors of xanthone biosynthesis which has been studied in cell cultures of Hypericum androsaemum (Hypericaceae) and Centaurium erythraea (Gentianaceae). In both cell cultures, methyl jasmonate induces the intracellular accumulation of a new xanthone. Under these inductive conditions, feeding experiments were performed with [U-14C]L-phenylalanine, [7-14C]benzoic acid and [7-14C]3-hydroxybenzoic acid. All three precursors were efficiently incorporated into the elicited xanthone in H. androsaemum, whereas 3-hydroxybenzoic acid was the only precursor to be incorporated into xanthones in C. erythraea. In addition, an appreciable increase in phenylalanine ammonia-lyase activity occurred only in methyl-jasmonate-treated cell cultures of H. androsaemum. Benzoic acids thus appear to be formed by different pathways in the two cell cultures studied. In H. androsaemum, benzoic acid is derived from cinnamic acid by side-chain degradation. In C. erythraea 3-hydroxybenzoic acid appears to originate directly from the shikimate pathway.

Complexation Dynamics of Xanthone and Thioxanthone to β-Cyclodextrin Derivatives

Abstract: The complexation dynamics of xanthone to substituted β-cyclodextrins (CDs) and of thioxanthone to β-CD was studied by directly following the relocation of the excited triplet-state ketones from the...

Xanthones from Garcinia parvifolia.

Abstract: Nine new xanthones, parvixanthones A-I (1-9), isolated from the dried bark of Garcinia parvifolia, were found to have a common 1,3,6,7-oxygenated pattern for their xanthone nucleus, but various oxygenated isoprenyl or geranyl substituent groups. The structures were determined by spectroscopic methods.

Chemical constituents from Drypetes littoralis.

Abstract: Chemical investigation of Drypetes littoralis yielded three new tricyclic diterpenes, drypetenones A, B, and C (1−3), and one new xanthone (4). Spectral analyses and chemical correlations establish...

Two new xanthone glycosides from Swertia tetraptera

Abstract: Two new xanthone glycosides, tetraswerosides A and B, were isolated from the whole plant of Swertia tertraptera. Their structures were determined as 3-O-beta -D-glucopyranosyl-1-hydroxy-4,7-dimethoxyxanthone and 3-O-[beta -D-xylopyranosyl-(1-->6)-beta -D-glucopyranosyl]-1- hydroxy-4,7-dimethoxyxanthone by spectroscopic methods.

Dichromenoxanthones from Tovomita brasiliensis.

Abstract: Two dichromenoxanthones [1,6-dihydroxy-6′,6′-dimethylpyrano(2′,3′:3,4)-6″,6″-dimethylpyrano(2″,3″:7,8)xanthone (brasilixanthone A) and 1,6-dihydroxy-6′,6′-dimethylpyrano(2′,3′:2,3)-6″,6″-dimethylpyrano(2″,3″:7,8 )xanthone (brasilixanthone B)], along with betulinic acid, friedelin, sitosterol and stigmasterol were isolated from the roots and stems of Tovomita brasiliensis . Their structures were characterized on the basis of 1 H and 13 C NMR spectral data, including 2D NMR experiments.

Isolation and identification of two new compounds from Erigeron breviscapus

Abstract: Object To investigate the chemical constituents of Erigeron breviscapus (Vant.) Hand. Mazz. (Compositae) Methods Compounds were isolated from the ethanolic extract with column chromatography and identified on the basis of spectral analysis (IR, EI MS, FAB MS, 1HNMR, 13 CNMR, 2DNMR) and physiochemical properties Results Two compounds were identified as 1 hydroxy 2,3,5 trimethoxy xanthone (Ⅴ), and 1 (2′ γ pyranone) 6 caffeoyl α D pyranoglucose (Ⅵ) Conclusion Both of the two compounds were new Compound Ⅵ showed inhibitory effects on the adhesion of endothelial induced by TNF α, indicating its protective effect against injury due to ischemic reperfusion

Chemical studies on new xanthone from Swertia decora

Abstract: Six compounds were isolated from the CHCl_(3) part of the extracts. Their structures were determined as 1-hydroxy-4, 5, 6, 7-tetramethoxyxanthone (swertiadecoraxanthone-I)(I), 1, 3, 8-trihydroxy-2, 5-dimethoxyxanthone (II), 1, 8-dihydroxy-3, 7-dimethoxy xanthone (methylswertianin, III), 1-hydroxy-3, 7, 8-trimethoxyxanthone (decussatin, IV), 1, 7, 8-trihydroxy-3-methoxyxanthone(swertianin, V) and tetracosanoic acid (VI), respectively. II named as swertiadecoraxanthone-II was a new compound and the others were found from this plant for the first time.

[1]Benzopyrano[2,3,4‐i,j]isoquinolines: A New, Versatile Route from 1‐Bromoxanthones.

Abstract: [1]Benzopyrano[2,3,4- i , j ]isoquinolines were synthesized from a bromoxanthone by assembly of the isoquinoline ring in three steps: vinylation, hydroamination and ring-closing reduction of the xanthone carbonyl.