Four new isoflavonoids from the stem bark of Erythrina variegata

Bioassay-directed fractionation of the stem bark extract of Erythrina variegata L. has resulted in the isolation of three new isoflavones: 5,4'-dihydroxy-8-(3,3-dimethylallyl)-2'-methoxyisopropylfurano[4,5:6,7]isoflavone (1), 5,7,4'-trihydroxy-6-(3,3-dimethylallyloxiranylmethyl)isoflavone (2), 5,4'-dihydroxy-8-(3,3-dimethylallyl)-2'-hydroxymethyl-2'-methylpyrano[5,6:6,7]isoflavone (3) and a new isoflavanone, 5,4'-dihydroxy-2'-methoxy-8-(3,3-dimethylallyl)-2',2'-dimethylpyrano[5,6:6,7]isoflavanone (4) together with seven known compounds, euchrenone b10 (5), isoerysenegalensein E (6), wighteone (7), laburnetin (8), lupiwighteone (9), erythrodiol (10), and oleanolic acid (11). The structures were determined on the basis of spectroscopic analyses and chemical evidence. The effect of these compounds on the proliferation of rat osteogenic sarcoma (UMR106) is also reported.     

由2',4'-二氢-6'-甲氧基-3',5'-二甲基查耳酮合成新黄酮

在DMSO/ I2的氧化作用下,由2',4'-二氢-6'-甲氧基-3',5'-二甲基查耳酮可合成一种全新结构的黄酮:7-羟基-5-甲氧基-6,8-二甲基黄酮(产率91%),而在HCl/MeOH作用下则得到了两种黄烷酮:7-羟基-5-甲氧基-6,8-二甲基黄烷酮 (产率70%) 和 5,7-二羟基-6,8-二甲基黄烷酮 (产率20%).     

Two new isoflavanoids from the rhizomes of Iris soforana

Two new isoflavones 1 and 2 along with eleven known compounds 3-13, have been isolated for the first time from the rhizomes of Iris soforana. The structures of these compounds were determined on the basis of spectroscopic methods and found to be 5,3'-dihydroxy-4'-methoxy-6,7-methylenedioxyisoflavone (1) (Soforanarin A), and 5,7,5'-trimethoxy-6,3',4'-trihydroxyisoflavone (2) (Soforanarin B).     

Protective effect against oxygen reactive species and skin fibroblast stimulation of Couroupita guianensis leaf extracts

In this study, hydroalcoholic leaf extracts of Couroupita guianensis were examined for antioxidant activity, phytochemical and total phenolic composition, stimulation of human skin fibroblast (HSF) proliferation and UV-absorption. The radical scavenging capacity, reducing power and protection against joint oxidation of linoleic acid and β-carotene bleaching oxidation in emulsion were used to evaluate the antioxidant activity. The results of this study strongly indicate in?vitro antioxidant activity, which may be due to the presence of a high total phenolic content. In order to identify active principles, the extracts were submitted to fractionation and the compounds isolated were the flavonoids 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (1), 7-hydroxy-5-methoxy-6,8-dimethylflavanone (2) and the phenolic acid 4-hydroxybenzoic acid (3). In addition, a high level of stimulation of HSF proliferation and significant absorption of UV radiation were also observed. The results suggest that the hydroalcoholic leaf extracts of C. guianensis have promising skin care properties.     

Prenylisoflavone derivatives from the roots of Hedysarum scoparium

Four new prenylisoflavone derivatives, namely, 5-hydroxy-4'-methoxy-8-prenyl-2'-hydroxyisopropyldihydrofurano[4,5:6,7]-isoflavone (1), 5-hydroxy-4'-methoxy-6-prenyl-2'-hydroxyisopropyldihydrofurano[4,5:8,7]-isoflavone (2), 5-hydroxy-4'-methoxy-8-prenyl-1',2'-peroxyl-3',3'-dimethyldihydropyrano[5,6:6,7]-isoflavone (3), and 5-hydroxy-4'-methoxy-6-prenyl-1',2'-peroxyl-3',3'-dimethyldihydropyrano[5,6:8,7]-isoflavone (4), together with three known ones 5-7, were isolated from the roots of Hedysarum scoparium. Their structures were established by means of detailed spectroscopic analysis (IR, EI- or HR-ESI-MS as well as 1D- and 2D-NMR), and by comparison of their spectroscopic data with those reported for structurally related compounds.     

New antioxidant bibenzyl derivative and isoflavonoid from the Tunisian Salsola tetrandra Folsk

Two new phytochemical compounds, Tetranins A and B, 1-(3,5'-dihydroxy-4'-méthoxyphenyl)-2-phenylethanol 1 and 5,2'-dihydroxy-5'-methoxy-6,7-methylenedioxy-isoflavone 2, were isolated from the EtOAc extract of Salsola tetrandra roots. They exhibited a significant antioxidant effect in 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assays. Their structures were elucidated by extensive spectroscopic methods including 1-D-((1)H and (13)C) and 2-D-NMR experiments (CHcorr, HMBC, (1)H-(1)H COSY and NOESY) as well as high-resolution ES-MS and they were found to be quite active as antioxidants in the DPPH and ABTS assays.     

New stilbenoids from Pholidota yunnanensis and their inhibitory effects on nitric oxide production

Six new stilbenoids, a (bibenzyldihydrophenanthrene) ether designated phoyunnanin D (1), a bis(dihydrophenanthrene) ether designated phoyunnanin E (2), and four stilbenes designated phoyunbene A-D (3-6), were isolated from the air-dried whole plant of Pholidota yunnanensis ROLFE. The new compounds were identified as 7-[2-(3-hydroxyphenethyl)-4-hydroxy-6-methoxyphenoxy]-4-hydroxy-2-methoxy-9,10-dihydrophenanthrene (1), 1-[(9,10-dihydro-4-hydroxy-2-methoxy-7-phenanthrenyl)oxy]-4,7-dihydroxy-2-methoxy-9,10-dihydrophenanthrene (2), trans-3,3'-dihydroxy-2',4',5-trimethoxystilbene (3), trans-3,4'-dihydroxy-2',3',5-trimethoxystilbene (4), trans-3,3'-dihydroxy-2',5-dimethoxystilbene (5), and trans-3-hydroxy-2',3',5-trimethoxystilbene (6) based on spectroscopic evidence. Furthermore, the inhibitory effects of compounds 1-6 on nitric oxide production in a murine macrophage-like cell line (RAW 264.7) activated by lipopolysaccharide and interferon-gamma were examined.     

Allergy-preventive flavonoids from Xanthorrhoea hastilis

Allergy-preventive activity was demonstrated for an extract of resins from Xanthorrhoea hastilis R. BR. in a search for allergy-preventive substances from natural sources. By bioassay-directed fractionation of this plant extract, a new flavanone, 3',5'-dihydroxy-7,4'-dimethoxyflavanone (1), and two new chalcones, 3,5,2'-trihydroxy-4,4'-dimethoxychalcone (2) and 5,2'-dihydroxy-3,4,4'-trimethoxychalcone (3), were isolated together with five known compounds, 5'-hydroxy-7,3',4'-trimethoxyflavanone (4), 3'-hydroxy-7,4'-dimethoxyflavanone (5), liquiritigenin 7-methyl ether (6), 4,2'-dihydroxy-4'-methoxychalcone (7) and sakuranetin (8). The structures of 1, 2 and 3 were elucidated by spectroscopic methods. All of these compounds showed allergy-preventive effects.     

Rapid Identification of Bibenzyls of Stemona sessilifolia using Hyphenated LC-UV-NMR and LC-MS Methods

IntroductionThe genusStemonacontains about 25 species,among whichS. sessilifolia,S. japonica,andS. tu-berosahave long been prescribed in traditional Chinesemedicine as insecticides and antitussive agents[1—4].The extracts of the roots of these three spec…     

Antioxidant activity of a new aromatic geranyl derivative of the resinous exudates from Heliotropium glutinosum Phil

Heliotropium glutinosum Phil. (Heliotropiceae) is a resinous bush that grows at a height of 2000 m in Cha?aral, Chile. From the resinous exudates of Heliotropium glutinosum Phil. a new aromatic geranyl derivative: 4-methoxy-3-[(2)-7'-methyl-3'-hydroxymethyl-2',6'-octadienyl] phenol (1) and three flavonoids: 5,3'-dihydroxy-7,4'-dimethoxyflavanone (2), 5,4'-dihydroxy-7-methoxyflavanone (3) and 4'-acetyl-5-hydroxy-7-methoxyflavanone (4) were isolated and their structures were determined. Their antioxidant activity were evaluated using the bleaching of ABTS and DPPH derived cation radical methods and expressed in terms of FRE (fast reacting equivalents) and TRE (total reacting equivalents), where FRE is a good measure of the quick protection of a given compound against oxidants and TRE measures the degree of long-term protection of the antioxidant, or how effective it is against a strong oxidative stress.     

Prenylated isoflavones from Flemingia philippinensis

Two new prenylated isoflavones, named flemiphilippinins E and F, were isolated from the roots of Flemingia philippinensis, together with six known ones. The structures of the above compounds were established by spectroscopic methods. Flemiphilippinins E and F were identified as 5,4'-dihydroxy-8-(3,3-dimethylallyl)-6',6'-dimethyl-5'-(1,1-dimethylallyl) pyrano(2',3':7,6)isoflavone and 5,4'-dihydroxy-4',4',5'-trimethyl-4',5'-dihydrofurano(2',3':7,8) isoflavone, respectively, by a combination of HR-EI-MS, (1)H NMR, (13)C NMR, HMQC, HMBC, and NOESY spectra.     

Antibacterial activity of the flavonoids from Dalbergia odorifera on Ralstonia solanacearum

Phytohemical investigation on the heartwood of Dalbergia odorifera resulted in the isolation of nine flavonoids. Their structures were elucidated as sativanone (1), (3R)-vestitone (2), (3R)-2',3',7-trihydroxy-4'-methoxyisoflavanone (3), (3R)-4'-methoxy-2',3,7-trihydroxyisoflavanone (4), carthamidin (5), liquiritigenin (6), isoliquiritigenin (7), (3R)-vestitol (8), and sulfuretin (9) based on their spectral data. All compounds were evaluated for their inhibitory activity against Ralstonia solanacearum. This is the first report about anti-R. solanacearum activity of the compounds from D. odorifera.     

Liquid chromatography-electrospray ionization mass spectrometry study of the flavonoids of the roots of Astragalus mongholicus and A. membranaceus

High-performance liquid chromatography-electrospray ionization mass spectrometry has been applied to analyze the flavonoids of Huangqi, the roots of Astragalus mongholicus and A. membranaceus. Eight flavonoids were identified as calycosin-7-O-beta-D-glucoside, calycosin-7-O-beta-D-glucoside-6"-O-malonate (2), ononin, (6aR,11aR)-3-hydroxy-9,10-dimethoxypterocarpan-3-O-bet a-D-glucoside, calycosin, (3R)-7,2'-dihydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside, formononetin-7-O-beta-D-glucoside-6"-O-malonate and formononetin by direct comparison with the isolated standards from Huangqi. The existence of (6aR,11aR)-3-hydroxy-9,10-dimethoxypterocarpan, (3R)-7,2'-dihydroxy-3',4'-dimethoxyisoflavan, astrapterocarpanglucoside-6'-O-malonate and astraisoflavanglucoside-6'-O-malonate was detected. This is the first report of flavonoid glycoside malonates in these two Astragalus species, and malonate 2 is a structurally completely identified new compound.     

Prenylated flavonoids with PTP1B inhibitory activity from the root bark of Erythrina mildbraedii

Phytochemical study on an EtOAc-soluble extract of the root bark of Erythrina mildbraedii resulted in the isolation of six prenylated flavonoids 1-6. Based on physicochemical and spectroscopic analyses, their structures were determined to be new natural products licoflavanone-4'-O-methyl ether (1), 2',7-dihydroxy-4'-methoxy-5'-(3-methylbut-2-enyl)isoflavone (2), and (3R)-2',7-dihydroxy-3'-(3-methylbut-2-enyl)-2',2'-dimethylpyrano[5',6' :4',5']isoflavan (3), along with three known compounds erythrinin B (4), abyssinin II (5), and parvisoflavone B (6). All the isolates, except for compound 4, inhibited PTP1B activity in vitro with IC(50) values ranging from 5.3 to 42.6 microM. This result further suggests that the prenyl group on the B ring of flavonoids plays an important role in suppressing the enzyme PTP1B.     

A new hydrochalcone from Miliusa sinensis

A new dihydrochalcone 4',6'-dihydroxy-2',3',4-trimethoxydihydrochalcone (1) along with nine known compounds, pashanone (2), dihydropashanone (3), pinostrobin (4), 5-hydroxy-7,4'-dimethoxyflavanone (5), 5-hydroxy-6,7-dimethoxyflavanone (6), 5-hydroxy-7,8-dimethoxyflavanone (7), 24-methylencycloartane-3β,21-diol (8), liriodenine (9) and 3,5-dihydroxy-7,3',4'-trimethoxyflavone (10), were isolated from the extracts, exhibiting cytotoxic activity (n-hexane and ethyl acetate extracts) of Miliusa sinensis. The structure of (1) was elucidated by the analysis of spectral data (IR, HR-MS, EI-MS, 1D and 2D NMR).     

Biotransformation of a C-glycosylflavone, abrusin 2''-O-beta-D-apioside, by human intestinal bacteria

After anaerobic incubation of abrusin 2'-O-beta-D-apioside (1) with a human fecal suspension, five metabolites were isolated and identified as abrusin (2), 1-(2',6'-dihydroxy-3',4'-dimethoxyphenyl)-3-(4'-hydroxyphenyl)propan-1- one (5), 5,6-dimethoxybenzene-1,3-diol (6), 3-(4'-hydroxyphenyl)propionic acid (7) and 3-phenylpropionic acid (8). However, methyl ether derivatives of abrusin (4'-O-methylabrusin and 4'-O-, 5-O-dimethylabrusin) resisted degradation under the same conditions.     

A new 3-arylcoumarin from the roots of an Egyptian collection of Lotus polyphyllos

Further investigation of different fractions from Lotus polyphyllos Clarke roots resulted in the isolation of the new 3-arylcoumarin derivative; 4',6'-dihydroxy-7, 2'-dimethoxy-3-arylcoumarin (5). In addition, the known compounds beta-sitosterol, 1-hexacosanol (1), n-tetracosyl p-coumarate (2), 4'-O-methylderrone (4), and quercetin (6) were identified. The structures were determined from spectroscopic data including 1D- and 2D-NMR experiments.     

A new type of stilbene-related secondary metabolite, idenburgene, from Cryptocarya idenburgensis

A new type of natural product, idenburgene (1), was isolated from Crytocarya idenburgensis, and its unique structure was elucidated. Four known compounds, 3-hydroxy-5-methoxystilbene (2), 2',6'-dihydroxy-4'-methoxydihydrochalcone (3), stigmast-4-ene-3-one, and beta-sitosterol were also isolated and identified.     

Carotenoids with two chromophores: carotenoid retinoates

In this study, carotenoid retinoates are described for the first time. The preparation was achieved by the azolide method. Various sec carotenols reacted with N-retinoylimidazol in the presence of catalytic amounts of sodium hydride. Mono- and diretinoates of (3R,3'R)-zeaxanthin and its (3S,3'S)-enantiomer, (9Z,9'Z; 3R,3'R)-alloxanthin, (3R,3'R)-7,8,7',8'-tetrahydro-3,3'-dihydroxy-β,β-carotene-8,8'-dione and (3R,6R,3'R,6'R)-ε,ε-carotene-3,3'-diol (lactucaxanthin), as well as monoretinoates of (3R,3'RS,6'R)-3'-methoxy-β,ε-caroten-3-ol, (3R,3'RS,6'R)-3-methoxy-β,ε-caroten-3'-ol, (2R,6'RS)-β,ε-caroten-2-ol, (3R,3'S; meso)-astaxanthin and (2'R)-aleuriaxanthin are reported in this study. Spectroscopic properties ((1)H-NMR mass spectrometry, visible and circular dichroism spectra) are discussed. Studies on other carotenoid derivatives with two chromophores are referred to here.     

Isolation and characterisation of bioactive isoflavonoids from the roots of Dalbergia horrida

The roots of Dalbergia horrida yielded two new isoflavanones, Dalhorridin (I) - 5,5'-dihydroxy-3',4'-methylenedioxy-5'-prenyl-6',6'-dimethyl-dihydropyrano(2',3' : 7,8)-isoflavanone and Dalhorridinin (II) - 5,7,5'-trihydroxy-3',4'-methylenedioxy-8-[5-methyl-2-(2-hydroxyisopropyl)-1,4-hexadienyl]isoflavanone along with two known isoflavones, Dalspinin and Dalspinosin. Preliminary biological screening of the enriched extract revealed that it showed analgesic, anti-inflammatory, CNS depressant and mild anti-bacterial properties.