Antimicrobial and radical scavenging flavonoids from the stem wood of Erythrina latissima

From the stem wood of Erythrina latissima, two isoflavones and a flavanone were isolated and characterized as 7,3'-dihydroxy-4'-methoxy-5'-(gamma,gamma-dimethylallyl)isoflavone (erylatissin A), 7,3'-dihydroxy-6',6'-dimethyl-4',5'-dehydropyrano [2',3': 4',5']isoflavone (erylatissin B), (-)-7,3'-dihydroxy-4'-methoxy-5'-(gamma,gamma-dimethylallyl)flavanone (erylatissin C), respectively, in addition to 10 known flavonoids. Structures of these compounds were determined on the basis of their spectroscopic data. These compounds showed antimicrobial activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida mycoderma. The isolated compounds also exhibited weak radical scavenging properties towards DPPH radical.     

Antimicrobial and antioxidant flavonoids from the root wood of Bolusanthus speciosus

Three new flavonoids-5,7,4'-trihydroxy-6-[1-hydroxy-2-methylbuten-2-yl]isoflavone (isogancaonin C), 7,2'-dihydroxy-4'-methoxyisoflav-3-ene (bolusanthin III), 6,6'-dihydroxy-4'-methoxy-2-arylbenzofuran (bolusanthin IV), in addition to eight known flavonoids; derrone, medicarpan, genistein, wighteone, lupiwighteone, gancaonin C, 7-hydroxy-4'-methoxyisoflavone and 7,3'-dihydroxy-4'-methoxyisoflavone were isolated from the root wood of Bolusanthus speciosus. The compounds showed strong antimicrobial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Candida mycoderma. The isolated compounds also showed moderate to strong radical scavenging properties against DPPH radical with the highest activities shown by the 2-arylbenzofuran, the isoflav-3-ene and 7,3'-dihydroxy-4'-methoxyisoflavone in decreasing order.     

Prenylated flavonoids of the leaves of Macaranga conifera with inhibitory activity against cyclooxygenase-2

Two prenylated flavonoid derivatives, 5-hydroxy-4'-methoxy-2",2"-dimethylpyrano-(7,8:6",5")flavanone (1) and 5,4'-dihydroxy-[2"-(1-hydroxy-1-methylethyl)dihydrofurano]-(7,8:5",4")flavanone (2), were isolated from an ethyl acetate-soluble extract of the leaves of Macaranga conifera using an in vitro activity-guided fractionation procedure based on the inhibition of cyclooxygenase-2. Also obtained were eight known compounds, 5,7-dihydroxy-4'-methoxy-8-(3-methylbut-2-enyl)flavanone (3), lonchocarpol A (4), sophoraflavanone B (5), 5,7-dihydroxy-4'-methoxy-8-(2-hydroxy-3-methylbut-3-enyl)flavanone (6), tomentosanol D (7), lupinifolinol (8), isolicoflavonol (9), and 20-epibryonolic acid (10). The structures of compounds 1 and 2 were determined using spectroscopic methods. All isolates were tested for their inhibitory effects against both cyclooxygenases-1 and -2, and selected compounds were evaluated in a mouse mammary organ culture assay.     

Coumarins from Malaysian Micromelum minutum

In a continuation of our study of the Rutaceae, detailed chemical investigation on Micromelum minutum (Rutaceae) collected from Sepilok, Sabah, Malaysia gave four new coumarins. The structures of the coumarins have been fully characterised by spectroscopic methods as 3",4"-dihydrocapnolactone 1, 2',3'-epoxyisocapnolactone 2, 8-hydroxyisocapnolactone-2',3'-diol 3 and 8-hydroxy-3",4"-dihydrocapnolactone-2',3'-diol 4.     

Flavonoids from the roots of Millettia erythrocalyx

From the roots of Millettia erythrocalyx, 6-methoxy-[2",3":7,8]-furanoflavanone, 2,5-dimethoxy-4-hydroxy-[2",3":7,8]-furanoflavan, and 3,4-methylenedioxy-2',4'-dimethoxychalcone were isolated, along with ten other known flavonoids. Their structures were elucidated on the basis of analyses of their spectroscopic data.     

Isoflavonoids from roots of Erythrina zeyheri

Five isoflavonoids, (+/-)-7,2',4'-trihydroxy-8,3'-di(gamma,gamma-dimethylallyl)isoflavanone, (3R)-7,4'-dihydroxy-2'-methoxy-6,8-di(gamma,gamma-dimethylallyl)isoflavanone, (3R)-7,2',4'-trihydroxy-6,8-di(gamma,gamma-dimethylallyl)isoflavan, 2',4'-dihydroxy-8-gamma,gamma-dimethylallyl-2",2"-dimethylpyrano-[5,6:6,7]isoflavan and (6aS, 11aS)-3,6a-dihydroxy-9-methoxy-4,10-di(gamma,gamma-dimethylallyl)pterocarpan, along with five known compounds, were isolated from the roots of Erythrina zeyheri. Their structures were established on the basis of spectroscopic evidence, and their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) were estimated by determining minimum inhibitory concentrations.     

Chemotaxonomic relevance of cardenolides in Urginea fugax

In a chemotaxonomic approach the investigation of a methanolic extract of bulbs of Urginea fugax (MORIS) STEINH. resulted in the detection of several cardenolides. The structure of a novel compound, named fugaxin (1), was established as 12alpha,14beta-dihydroxy-2alpha,3beta-(tetrahydro-3',5'-dihydroxy-4'-methoxy-6'-methyl-2H-pyran-2',4'-diylbisoxy)-card-4,20-dienolide by extensive NMR spectroscopic studies including 2D-NMR techniques (COSY, HSQC, HMQC) and selective 1D experiments (NOE, TOCSY) as well as HR-ESI-MS. The chemotaxonomic relevance of the occurrence of cardenolides in the genus Urginea is discussed.     

Three isoflav-3-enes and a 2-arylbenzofuran from the root bark of Erythrina burttii

From the root bark of Erythrina burttii three isoflav-3-enes, 7,4'-dihydroxy-2'-methoxy-6-(1",1"-dimethylallyl)isoflav-3-ene (trivial name, burttinol-A), 4'-hydroxy-2'-methoxy-2",2"-dimethylpyrano[5",6":8,7]isoflav-3-ene (trivial name, burttinol-B), 7,4'-dihydroxy-2'-methoxy-8-(3",3"-dimethylallyl)isoflav-3-ene (trivial name, burttinol-C), and 2-arylbenzofuran, 6,4'-dihydroxy-2'-methoxy-5-(1",1"-dimethylallyl)-2-arylbenzofuran (trivial name, burttinol-D) were isolated. In addition, the known compounds, abyssinone V-4'-methyl ether, bidwillol A, calopocarpin, erybraedin A, erythrabyssin II, isobavachalcone, phaseollidin and phaseollin were identified. The structures were determined on the basis of spectroscopic evidence.     

Antimicrobial constituents from the stem bark of Feronia limonia.

The stem bark of Feronia limonia (Fam. Rutaceae) yielded (-)-(2S)-5,3'-dihydroxy-4'-methoxy-6",6"-dimethylchromeno-(7,8,2",3")-flavanone along with several known compounds including an alkaloid, five coumarins, a flavanone, a lignan, three sterols and a triterpene. The structures of these compounds were determined by spectroscopic methods, mainly 1D and 2D NMR. The antimicrobial screening of compounds by a microdilution technique resulted in MICs in the range 25-100 microg/ml. Other biological activities of the known compounds are also discussed.     

Identification of galloylated propelargonidins and procyanidins in buckwheat grain and quantification of rutin and flavanols from homostylous hybrids originating from F. esculentumxF. homotropicum

The flavonoid rich grain of buckwheat (Fagopyrum esculentum Moench, Fam. Polygonaceae) is of high nutritional value. With the aim to improve its agronomic productivity, cultivars were crossed with the wild species F. homotropicum which, however, differs in its flavonoid content. The intention of this work was to determine the flavonoid composition in developed interspecific hybrids and to elucidate the proanthocyanidin structures. Seven compounds were purified from methanol extracts of buckwheat (Fagopyrum esculentum Moench) grains by Sephadex LH-20 column chromatography. Beside the procyanidin epicatechin-[4-8]-epicatechin-3-O-(3,4)-dimethylgallate the following propelargonidins were identified: epiafzelechin-[4-6]-epicatechin, epiafzelechin-[4-8]-epiafzelechin-[4-8]-epicatechin, epiafzelechin-[4-8]-epicatechin-3-O-(3,4-dimethyl)-gallate, epiafzelechin-[4-8]-epiafzelechin-[4-8]-epicatechin-3-O-(3,4-dimethyl)-gallate, epiafzelechin-[4-8]-epicatechin-3-O-4-methyl-gallate and epiafzelechin-[4-8]-epicatechin-p-OH-benzoate on the basis of HPLC and LC-MS/MS.     

膜荚黄芪中两个新的抗菌异黄烷化合物

膜荚黄芪（Astragalus membranaceus (Fisch.)Bunge）为豆科植物,其根入药,有补气固表、利尿脱毒、敛疮疤生肌、益气补中之功效,主要用于气虚乏力、食少便溏、中气下陷、久泻脱肛、便血崩漏、表虚自汗、气虚     

GC-MS analysis of the essential oils, and the isolation of phenylpropanoid derivatives from the aerial parts of Pimpinella aurea

A combination of vacuum liquid chromatography (VLC) and preparative thin layer chromatography (PTLC) of the dichloromethane extract of the aerial parts of the Iranian plant Pimpinella aurea afforded two phenylpropanoids, erythro-1'-(4-methoxyphenyl)-propan-1',2'-diol (1) and erythro-1'-[4-(sec-butyl)-phenyl]-propan-1',2'-diol (2), the latter being a natural product. The structures of these compounds were determined by spectroscopic means. The antioxidant properties of these compounds were assessed by the DPPH assay. The GC-MS analysis of the essential oils of P. aurea provided a chemical profile that was significantly different from the previously published reports.     

Prenylated flavonoids, monoterpenoid furanocoumarins and other constituents from the twigs of Dorstenia elliptica (Moraceae)

A monoprenylated flavan and two monoterpenoid substituted furanocoumarins were isolated from the twigs of Dorstenia elliptica along with 3-(3,3-dimethylallyl)-4,2',4'-trihydroxylchalcone, psoralen, bergapten, O-[3-(2,2-dimethyl-3-oxo-2H-furan-5-yl)butyl]bergaptol, beta-sitosterol and its beta-D-glucopyranoside. The structure of the flavan was determined as 6(1,1-dimethylallyl)-7,4'-dihydroxylflavan and the monoterpenoid substituted furanocoumarins were assigned as O-[3-(2,2-dimethyl-3-oxo-2H-furan-5-yl)-3-hydroxybutyl]-bergaptol and O-[2-(5-hydroxy-2,6,6-trimethyl-3-oxo-2H-pyran-2-yl)ethyl]bergaptol, respectively, using spectroscopic analysis, especially, 2D NMR spectra.     

Alkaloids from Galanthus nivalis

Phytochemical studies on Galanthus nivalis of Bulgarian origin resulted in the isolation of five compounds: 11-O-(3'-hydroxybutanoyl)hamayne, 3,11-O-(3',3'-dihydroxybutanoyl)hamayne, 3-O-(2'-butenoyl)-11-O-(3'-hydroxybutanoyl)hamayne, 3,11,3'-O-(3',3',3'-trihydroxybutanoyl)hamayne, and 2-O-(3'-acetoxybutanoyl)lycorine, together with five known alkaloids: ungeremine, lycorine, tazettine, hamayne, and ismine. Their structures were determined by (1)H and (13)C NMR spectroscopy and two-dimensional (1)H-(1)H and (1)H-(13)C chemical shift correlation experiments.     

Antioxidant aryl-prenylcoumarin, flavan-3-ols and flavonoids from Eysenhardtia subcoriacea

Antioxidant activity (AOA) assay-guided chemical analysis, using a rat pancreas homogenate model, of aerial parts from Eysenhardtia subcoriacea, led to isolation of the new compound subcoriacin (3-(2'-hydroxy-4',5'-methylendioxyphenyl)-6-(3'-hydroxymethyl-4'-hydroxybut-2'-enyl)-7-hydroxycoumarin) together with the known substances: (+)-catechin, (-)-epicatechin, (+)-afzelechin, eriodictyol, (+)-catechin 3-O-beta-D-galactopyranoside and quercetin 3-O-beta-D-galactopyranoside as bioactive constituents. The structure of the compound was determined from 1D and 2D NMR spectroscopic analyses. Additional known constituents were characterized. The bioactive compounds showed also moderate to strong radical scavenging properties against diphenylpicrylhydrazyl radical (DPPH). In addition, subcoriacin, (+)-catechin, (-)-epicatechin and (+)-afzelechin improved the reduced glutathione levels in rat pancreatic homogenate.     

Phenolic derivatives from Wigandia urens with weak activity against the chemokine receptor CCR5

Three compounds, 2,3-dihydroxy-4-methoxy-6,6,9-trimethyl-6H-dibenzo[b,d]pyran (1), 8-methoxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran-6-ol (2) and 4-methoxy-3-(3-methyl-2-butenyl)-benzoic acid (3), have been isolated from Wigandia urens. The structures of compounds 1, 2 and 3 were determined from spectroscopic data and showed activity in a CCR5 assay with IC(50) values of 33, 46 and 26 muM respectively.     

Alpha-pyrones and a 2(5H)-furanone from Hyptis pectinata

Three pyrones and a 2(5H)-furanone, designated pectinolides D-G, have been isolated from the dichloromethane extract of Hyptis pectinata. The metabolites were characterized on the basis of 1D and 2D NMR spectroscopic techniques. The pyrones were identified as 6S-[3S,6S-(diacetoxy)-5R-hydroxy-1Z-heptenyl]-5S-hydroxy-5,6-dihydro-2H-pyran-2-one (1)- pectinolide D, 6S-[3S,5R,6S-(triacetoxy)-1Z-heptenyl]-5S-acetoxy-5,6-dihydro-2H-pyran-2-one (2)- pectinolide E and 6S-[3S,5R,6S-(triacetoxy)-1Z-heptenyl]-5S-acetoxy-4R-methoxy-3,4,5,6-tetrahydro-4H pyran-2-one (3)- pectinolide F. The furanone was identified as [2'Z,5(1')Z] 5-(4'S,6'R,7'S-triacetoxy-2-octenylidene)-2(5H)-furanone (4)-pectinolide G.     

Flavonoids from two Lonchocarpus species of the Yucatan Peninsula

Leaves, stem bark and root of Lonchocarpus xuul and Lonchocarpus yucatanensis were studied separately. A chalcone, 2',4-dimethoxy-6'-hydroxylonchocarpin (), and the flavones 5,4'-dihydroxy-3'-methoxy-(6:7)-2,2-dimethylpyranoflavone (2) and 5,4'-dimethoxy-(6:7)-2,2-dimethylpyrano-flavone (3), together with the known carpachromene (4), were isolated from the leaves of both species. Similarly, the previously reported flavans xuulanin (5) and 3beta-methoxyxuulanin (6), together with the novel 3beta,4beta,5-trimethoxy-4'-hydroxy-(6:7)-2,2-dimethylpyranoflavan (7), 3-hydroxy-4,5-dimethoxy-(6:7)-2,2-dimethyl-pyranoflavan (8), and 3,4-dihydroxy-5-methoxy-(6:7)-2,2-dimethylpyranoflavan (10), were isolated from the stem bark and root of both species. Finally, the known 2',4'-dihydroxy-3'-(3-methylbut-2-enyl) chalcone (13) was obtained from the root of L. xuul only. The structures of the various metabolites were established by interpretation of their spectroscopic data.     

Metabolism of chlorambucil by rat liver microsomal glutathione S-transferase

Clinical efficacy of alkylating anticancer drugs, such as chlorambucil (4-[p-[bis [2-chloroethyl] amino] phenyl]-butanoic acid; CHB), is often limited by the emergence of drug resistant tumor cells. Increased glutathione (gamma-glutamylcysteinylglycine; GSH) conjugation (inactivation) of alkylating anticancer drugs due to overexpression of cytosolic glutathione S-transferase (GST) is believed to be an important mechanism in tumor cell resistance to alkylating agents. However, the potential involvement of microsomal GST in the establishment of acquired drug resistance (ADR) to CHB remains uncertain. In our experiments, a combination of lipid chromatography/electrospray ionization mass spectrometry (LC/ESI/MS) was employed for structural characterization of the resulting conjugates between CHB and GSH. The spontaneous reaction of 1mM CHB with 5 mM GSH at 37 degrees C in aqueous phosphate buffer for 1 h gave primarily the monoglutathionyl derivative, 4-[p-[N-2-chloroethyl, N-2-S-glutathionylethyl] amino]phenyl]-butanoic acid (CHBSG) and the diglutathionyl derivative, 4-[p-[2-S-glutathionylethyl] amino]phenyl]-butanoic acid (CHBSG2) with small amounts of the hydroxy-derivative, 4-[p-[N-2-S-glutathionylethyl, N-2-hydroxyethyl] amino]phenyl]-butanoic acid (CHBSGOH), 4-[p-[bis[2-hydroxyethyl] amino]phenyl]-butanoic acid (CHBOH2), 4-[p-[N-2-chloroethyl, N-2-S-hydroxyethyl]amino]phenyl]-butanoic acid (CHBOH). We demonstrated that rat liver microsomal GST presented a strong catalytic effect on these reactions as determined by the increase of CHBSG2, CHBSGOH and CHBSG and the decrease of CHB. We showed that microsomal GST was activated by CHB in a concentration and time dependent manner. Microsomal GST which was stimulated approximately two-fold with CHB had a stronger catalytic effect. Thus, microsomal GST may play a potential role in the metabolism of CHB in biological membranes, and in the development of ADR.