Iridoid and phenolic diglycosides from Canthium berberidifolium

An iridoid diglycoside, 6-O-beta-D-apiofuranosyl-mussaenosidic acid, and four phenolic diglycosides, canthosides A-D, were isolated from the aerial part of Canthium berberidifolium, along with seven known compounds. Structural elucidations were based on analyses of spectroscopic data.     

Degraded limonoids from Melia azedarach and biogenetic implications

The unique series of C-2'-acylated C-glycosylflavones is extended by the discovery of the C-8-glucosyl derivatives 2'-O-galloylvitexin and 2'-O-galloylorientin and their C-6 analogues 2'-O-galloylisovitexin and 2'-O-galloylisoorientin, representing the first described O-galloyl-C-glycosylflavones. They are accompanied in the aerial parts of Pelargonium reniforme by the known non-galloylated parent analogues vitexin, orientin, isovitexin and isoorientin, as well as several known flavonoid-O-glycosides. The structures of these compounds were established from spectroscopic studies. Differentiation between C-glycosylation at C-6 and C-8 is discussed on the basis of the effects of dynamic rotational isomerism.     

Diterpenoids from the pericarp of Platycladus orientalis

Eight labdane-type diterpenes, 7beta,13S-dihydroxylabda-8(17),14-dien-19-oic acid (1), 12R,15-dihydroxylabda-8(17),13E-dien-19-oic acid (3c), 12R,15-dihydroxylabda-8(17),13Z-dien-19-oic acid (3d), 12R,13R,14S-trihydroxylabda-12,15-epoxy-8(17)-en-19-oic acid (4a), 12S,13S,14R-trihydroxylabda-12,15-epoxy-8(17)-en-19-oic acid (4b), 15-hydroxy-12-oxolabda-8(17),13E-dien-19-oic acid (5), 14R,15-dihydroxylabda-8(17),12Z-dien-19-oic acid (7a) and 14S,15-dihydroxylabda-8(17),12Z-dien-19-oic acid (7b), along with 20 known diterpenoids, were isolated from the pericarp of Platycladus orientalis. Their structures were unambiguously elucidated by NMR spectroscopic and single crystal X-ray diffraction analyses, as well as via chemical correlation conversion. NMR spectroscopic data of known isomers 8c and 8d were reported as a supplement to existing data.     

Guaiane-type sesquiterpenoids from Alisma orientalis

Two guaiane-type sesquiterpenoids named orientalol E (1) and orientalol F (3) were isolated from the rhizome of Alisma orientalis (SAM) JUZEP together with two known guaiane-type sesquiterpenoids alismol (2) and alismoxide (4). Their relative stereostructures were elucidated by spectroscopic methods, whereas absolute stereostructures were determined on the basis of chemical correlation.     

Malonylated flavonol glycosides from the petals of Clitoria ternatea

Three flavonol glycosides, kaempferol 3-O-(2"-O-alpha-rhamnosyl-6"-O-malonyl)-beta-glucoside, quercetin 3-O-(2"-O-alpha-rhamnosyl-6"-O-malonyl)-beta-glucoside, and myricetin 3-O-(2",6"-di-O-alpha-rhamnosyl)-beta-glucoside were isolated from the petals of Clitoria ternatea cv. Double Blue, together with eleven known flavonol glycosides. Their structures were identified using UV, MS, and NMR spectroscopy. They were characterized as kaempferol and quercetin 3-(2(G)- rhamnosylrutinoside)s, kaempferol, quercetin, and myricetin 3-neohesperidosides, 3-rutinosides, and 3-glucosides in the same tissue. In addition, the presence of myricetin 3-O-(2"-O-alpha-rhamnosyl-6"-O-malonyl)-beta-glucoside was inferred from LC/MS/MS data for crude petal extracts. The flavonol compounds identified in the petals of C. ternatea differed from those reported in previous studies.     

Anthocyanins acylated with gallic acid from chenille plant, Acalypha hispida

Three anthocyanins were isolated from the red flowers of chenille plant, Acalypha hispida Burm. (Euphorbiaceae) by a combination of chromatographic techniques. Their structures were elucidated mainly by homo- and heteronuclear nuclear magnetic resonance spectroscopy and electrospray mass spectrometry, and supported with complete assignments of 13C NMR resonances. The novel pigment, cyanidin 3-O-(2"-galloyl-6"-O-alpha-rhamnopyranosyl-beta-galactopyranoside) (5%), contains the disaccharide robinoside. The other anthocyanins were identified as cyanidin 3-O-(2"-galloyl-beta-galactopyranoside) (85%), and cyanidin 3-O-beta-galactopyranoside (5%). Anthocyanins acylated with gallic acid have previously been identified in species from the families Nymphaeaceae and Aceraceae, and tentatively in Abrus precatorius (Leguminosae).     

Pathogenicity of intrathoracically administrated Bacillus thuringiensis spores in Blatta orientalis

The ability of Bacillus thuringiensis to produce septicaemia in Periplaneta americana and Blatta orientalis has been investigated. Spores and crystals from several wild-type strains as well as spores of a B. thuringiensis crystal-deficient mutant, were first orally administrated at high doses, and no significant mortality was recorded. Intrathoracic injection of spore suspensions in P. americana revealed that this species is not very susceptible to B. thuringiensis spores. B. orientalis, by contrast, was found to be very susceptible to B. thuringiensis, with a LD(50) of about 35,000 spores, that is similar to that reported on Lepidoptera challenged with parenterally injected B. thuringiensis.     

Phenolic glycosides from Barnettia kerrii

From the leaves and branches Barnettia kerrii, two verbascoside derivatives (6"-O-acetylverbascoside and 4"'-O-acetylverbascoside), as well as two phenolic glycosides (khaephuosides A and B) were isolated together with 15 known compounds. The structural elucidations were based on analyses of spectroscopic data.     

Stilbenes from the roots of Pleuropterus ciliinervis and their antioxidant activities

Two stilbene glycosides, pieceid-2"-O-gallate and pieceid-2"-O-coumarate, were isolated from the MeOH extract of the roots of Pleuropterus ciliinervis Nakai (Polygonaceae), together with two known compounds, resveratrol and pieceid. Their structures were determined spectroscopically, particularly by 2D NMR spectroscopic analysis. The antioxidant activities of stilbenes isolated were determined in vitro against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals and by determining their lipid peroxidation inhibitory activities. Among the compounds isolated, pieceid-2"-O-gallate had the most potent inhibitory scavenging effect on DPPH, superoxide radicals and upon lipid peroxidation inhibition with IC50 values of 16.5, 23.9 and 5.1 microM, respectively.     

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.     

Acylated farnesyl diglycosides from Guioa crenulata

Chemical investigation of the methanol extract of the leaves of Caledonian Guioa crenulata led to the isolation and characterisation of four farnesyl diglycosides, crenulatosides A, B, C and D, along with three known flavonol glycosides and one known trimeric proanthocyanidin possessing a doubly linked structure. The structures of these compounds were determined on the basis of spectroscopic studies and chemical evidence. The ethanol and ethyl acetate extracts of the leaves exhibited no cytotoxic activity and no inhibition of acetylcholinesterase.     

Antiplasmodial activity of sesquilignans and sesquineolignans from Bonamia spectabilis

Phytochemical re-investigation of the aerial parts of Bonamia spectabilis (Convolvulaceae) led to the isolation of four minor tetrahydrofuran-type sesquilignans (bonaspectins E-H) together with the known neolignan virolongin A and the known lignan rel-(7S,8R,7'R,8'R)-3,3',4,4',5,5'-hexamethoxylignan. Their structures were established on the basis of spectral data. These six compounds as well as further seven lignanoids from B. spectabilis, characterised previously, were tested for their antiplasmodial activity against a chloroquine-sensitive strain (PoW) and a chloroquine-resistant clone (Dd2) of Plasmodium falciparum. Bonaspectin C 4"-O-glucoside, its aglycone, and bonaspectin D 4"-O-glucoside revealed the highest antiplasmodial activities (IC50 values: 1.3, 2.0, 6.5 microM [PoW]; 1.7, 4.6, 3.7 microM [Dd2], respectively).     

Phloroglucinol diglycosides accompanying hydrolyzable tannins from Kunzea ambigua

Six phloroglucinol diglucosides—kunzeaphlogins A-F (1-6) and a hydrolyzable tannin, kunzeatannin A (7)—were isolated along with 10 known polyphenols from the leaf extract of Kunzea ambigua. Structural elucidation of these compounds was based on spectroscopic analyses and chemical properties.     

Effect of lignocellulosic inhibitory compounds on growth and ethanol fermentation of newly-isolated thermotolerant Issatchenkia orientalis

A newly isolated thermotolerant ethanologenic yeast strain, Issatchenkia orientalis IPE 100, was able to produce ethanol with a theoretical yield of 85% per g of glucose at 42 °C. Ethanol production was inhibited by furfural, hydroxymethylfurfural and vanillin concentrations above 5.56 g L⁻¹, 7.81 g L⁻¹, and 3.17 g L⁻¹, respectively, but the strain was able to produce ethanol from enzymatically hydrolyzed steam-exploded cornstalk with 93.8% of theoretical yield and 0.91 g L⁻¹ h⁻¹ of productivity at 42 °C. Therefore, I. orientalis IPE 100 is a potential candidate for commercial lignocelluloses-to-ethanol production.     

芦苇、香蒲和藨草3种挺水植物的养分吸收动力学

采用常规耗竭法研究了浅水富营养化湖泊———乌梁素海湖滨植被带3种挺水植物芦苇、香蒲和藨草对H2PO-4、NH+4、NO-3的吸收动力学特征及差异。结果表明:3种挺水植物吸收H2PO-4时,藨草的吸收速率显著大于芦苇和香蒲,但三者对低浓度H2PO-4的适应能力均无显著差异;藨草对NH+4和NO-3的吸收速率均显著大于芦苇和香蒲,且在低浓度NO-3环境下仍能吸收该离子,但对低浓度NH+4环境的适应能力较差;与藨草相比,香蒲对NH+4的亲和力最强,吸收低浓度NH+4的效果最好。3种植物对NH+4的吸收能力均大于NO-3。挺水植物的养分吸收特征具有物种特异性并受根系结构的影响。利用植物的养分吸收特征,在富营养化湖泊生态修复中适宜用藨草治理含高浓度H2PO-4,NH+4和NO-3的水体,修复到一定程度后再种植香蒲来维持水质。     

Monoamine oxidase inhibitors from Gentiana lutea

Three monoamine oxidase (MAO) inhibitors were isolated from Gentiana lutea. Their structures were elucidated to be 3-3'linked-(2'-hydroxy-4-O-isoprenylchalcone)-(2'-hydroxy-4'-O-isoprenyldihydrochalcone) (1), 2-methoxy-3-(1,1'-dimethylallyl)-6a,10a-dihydrobenzo(1,2-c)chroman-6-one and 5-hydroxyflavanone. These compounds, and the hydrolysis product of 1, displayed competitive inhibitory properties against MAO-B which was more effective than MAO-A.     

Cytotoxic Alangium alkaloids from Alangium longiflorum

Seven alkaloids (1-7) were isolated from the stem bark of Alangium longiflorum. Compound 1, (-)-10-O-demethylisocephaeline, was isolated for the first time as a naturally occurring product from a plant source. All structures were elucidated by detailed spectroscopic analysis. Biological evaluation showed that 2, 10-O-demethylcephaeline, exhibited potent cytotoxic activity against human lung carcinoma (A549) and breast adenocarcinoma (MCF-7) with ED(50) values of 0.013 and 0.062 microM, respectively. The stereoisomer 1 was less potent than 2, and related compounds with different hydroxy/methoxy substitution patterns were also less potent or inactive. Thus, compound 2 merits attention as a cytotoxic lead for further study.     

Aromatic compound glucosides,alkyl glucoside and glucide from the fruit of anise

From the polar portion of the methanolic extract of the fruit of anise (Pimpinella anisum L.), which has been used as a spice and medicine since antiquity, four aromatic compound glucosides, an alkyl glucoside and a glucide were isolated together with 24 known compounds. The structures of the new compounds were clarified as (E)-3-hydroxyanethole beta-D-glucopyranoside, (E)-1'-(2-hydroxy-5-methoxyphenyl)propane beta-D-glucopyranoside, 3-hydroxyestragole beta-D-glucopyranoside, methyl syringate 4-O-beta-D-glucopyranoside, hexane-1,5-diol 1-O-beta-D-glucopyranoside and 1-deoxy-L-erythritol 3-O-beta-D-glucopyranoside by spectral investigation.     

Phloroglucinol derivatives from Mallotus pallidus

From the leaves of Mallotus pallidus were isolated five phloroglucinol derivatives, namely pallidusol, dehydropallidusol, pallidol, mallopallidol and homomallopallidol. Their structures were determined by means of spectroscopic methods of analysis.