4种蔷薇属植物叶片黄酮含量的季节性变化

采用ＨＰＬＣ法对刺梨（Ｒｏｓａ ｒｏｘｂｕｒｇｈｉｉ Ｔｒａｔｔ．）等４种蔷薇属植物在不同生长季节叶片的总黄酮甙含量和甙元配比进行了分析测定。结果表明,不同采摘期的华西蔷薇（Ｒ．ｍｏｙｅｓｉｉ Ｈｅｍｓｌ．ｅｔ Ｗｉｌｓ．）绣球蔷薇（Ｒ．ｇｉｏｍｅｒａｔａ Ｒｅｈｄ．ｅ Ｗｉｌｓ．）和峨嵋蔷薇（Ｒ．ｏｍｅｉｅｎｓｉｓ Ｒｏｌｆｅ）的叶片总黄酮甙含量有较大的差异,一般在展叶期黄酮含量较低,随后叶片黄     

液相色谱/离子阱质谱法研究何首乌中糖苷类化合物

采用液相色谱／离子阱质谱（HPLC／IT-MS）联用技术研究何首乌中糖苷类化合物,并对大黄素甲醚糖苷和大黄素糖苷的分子离子或准分子离子的离子化机理进行探讨。实验采用反相C18色谱柱,二元线性梯度洗脱,分离出12个主要成分。利用质谱的诱导碰撞解离技术获得碎片裂解信息,结合文献鉴定出9种糖苷的化学结构,其中顺式-2,3,5,4＇-四羟基二苯乙烯-2-O-β-D-毗喃葡萄糖苷、决明酮-8—O-（6＇-O-乙酰基）-β—D-吡喃葡萄糖苷和大黄素甲醚-8-O-（6＇-O-乙酰基）-β-D-吡喃葡萄糖苷为首次鉴定。     

New phenolic glycosides isolated from Penthorum chinense Pursh

A phytochemical investigation from 80% ethanol extract of Penthorum chinense Pursh (Saxifragaceae) resulted in the isolation of three new phenolic glycosides (1–3), together with three known phenolic glycosides (4–6). The structures of the new compounds were deduced from their comprehensive spectroscopic analysis including IR, HR-EI-MS, ¹H NMR, ¹³C NMR, DEPT, COSY, HMBC and HMQC. And the structures of known compounds 4–6 were identified by comparison of their spectral data with those reported in the literature.     

Wheat leaf lipids during heat stress: I. High day and night temperatures result in major lipid alterations

Understanding how wheat (Triticum aestivum L.) plants under high temperature (HT) regulate lipid composition is critical to developing climate‐resilient varieties. We measured 165 glycerolipids and sterol derivatives under optimum and high day and night temperatures in wheat leaves using electrospray ionization‐tandem mass spectrometry. Levels of polar lipid fatty acyl chain unsaturation were lower in both heat‐tolerant genotype Ventnor and susceptible genotype Karl 92 under HT, compared with optimum temperature. The lower unsaturation was predominantly because of lower levels of 18:3 acyl chains and higher levels of 18:1 and 16:0 acyl chains. Levels of 18:3‐containing triacylglycerols increased threefold/more under HT, consistent with their possible role in sequestering fatty acids during membrane lipid remodelling. Phospholipids containing odd‐numbered or oxidized acyl chains accumulated in leaves under HT. Sterol glycosides (SG) and 16:0‐acylated sterol glycosides (ASG) were higher under HT than optimum temperatures. Ventnor had lower amounts of phospholipids with oxidized acyl chains under HT and higher amounts of SG and 16:0‐ASG than Karl 92. Taken together, the data demonstrate that wheat leaf lipid composition is altered by HT, in which some lipids are particularly responsive to HT, and that two wheat genotypes, chosen for their differing physiological responses to HT, differ in lipid profile under HT.     

Thiol addition to protected allyl glycosides: An improved method for the preparation of spacer-arm glycosides

A useful method for the preparation of differently functionalized sulfide spacer-arm glycosides is presented. Several protected allyl glycosides were variously elongated via a radical addition reaction with pentanethiol, methyl 3-mercaptopropionate, or 2-mercaptoethanol. The hydroxyl function of protected 3-(2-hydroxyethylthio)propyl glycosides was subsequently transformed into an azide function.     

Identification of linear plasmid pAM1 in the flavonoid degrading strain Actinoplanes missouriensis(T) (DSM 43046)

By pulsed-field gel electrophoresis, a linear DNA element of about 100 kb was identified in Actinoplanes missouriensis(T) DSM 43046, which grows on the flavonoids hesperidin, rutin and quercetin, and which contains a CO forming quercetinase. Among six Actinoplanes species and strains tested, including A. globisporus(T) DSM 43857, A. philippinensis(T) DSM 43019, A. brasiliensis(T) DSM 43805, A. auranticolor(T) DSM 43031, and A. utahensis(T) DSM 43147, only the A. missouriensis strain exhibited such a genetic element. The linear plasmid, named pAM1, has proteins covalently attached to its 5'-ends like other linear replicons of actinomycetes. Attempts to cure pAM1 failed, however a mutant with reduced plasmid content was obtained, which showed reduced ability to degrade the flavonoid rutinosides rutin and hesperidin. Plasmid pAM1 is the first extrachromosomal genetic element identified in an Actinoplanes species and may be useful to develop genetic tools for biotechnologically important Actinoplanes strains.     

The effects of enriched CO2 atmospheres on plant-insect herbivore interactions: growth responses of larvae of the specialist butterfly,Junonia coenia (Lepidoptera: Nymphalidae)

Summary Little is known about the effects of enriched CO₂ environments, which are anticipated to exist in the next century, on natural plant-insect herbivore interactions. To begin to understand such effects on insect growth and survival, I reared both early and penultimate instar larvae of the buckeye, Junonia coenia (Lepidoptera: Nymphalidae), on leaves from one of their major hostplants, plantain, Plantago lanceolata (Plantaginaceae), grown in either ambient (350 PPM) or high (700 PPM) CO₂ atmospheres. Despite consuming more foliage, early instar larvae experienced reduced growth on high CO₂-grown compared to ambient CO₂-grown leaves. However, survivorship of early instar larvae was unaffected by the CO₂ treatment. Larval weight gain was positively correlated with the nitrogen concentration of the plant material and consumption was negatively correlated with foliar nitrogen concentration, whereas neither larval weight gain nor consumption were significantly correlated with foliar water or allelochemical concentrations. In contrast, penultimate instar larvae had similar growth rates on ambient and high CO₂-grown leaves. Significantly higher consumption rates on high CO₂-grown plants enabled penultimate instar larvae to obtain similar amounts of nitrogen in both treatments. These larvae grew at similar rates on foliage from the two CO₂ treatments, despite a reduced efficiency of conversion of ingested food (ECI) on the low nitrogen, high CO₂-grown plants. However, nitrogen utilization efficiencies (NUE) were unaffected by CO₂ treatment. Again, for late instar larvae, consumption rates were negatively correlated with foliar nitrogen concentrations, and ECI was also very highly correlated with leaf nitrogen; foliar water or allelochemical concentrations did not affect either of these parameters. Differences in growth responses of early and late instar larvae to lower nitrogen, high-CO₂ grown foliage may be due to the inability of early instar larvae to efficiently process the increased flow of food through the gut caused by additional consumption of high CO₂ foliage.     

Water T2 relaxation in sugar solutions

1H spin-spin relaxation times of water were measured with the CPMG sequence in dilute aqueous solutions of glucitol, mannitol, glycerol, glycol, the methyl D-pyranosides of alpha-glucose, beta-glucose, alpha-galactose, beta-galactose, alpha-xylose, beta-xylose, beta-arabinose and sucrose, alpha,alpha-trehalose, beta-maltose, maltotriose and maltoheptaose. The relaxation-time dispersion was measured by varying the CPMG pulse spacing, tau. These data were interpreted by means of the Carver-Richards model in which exchange between water protons and labile solute hydroxyl protons provides a significant contribution to the relaxation. From the dependences on temperature and tau, parameters characteristic of the pool of hydroxyls belonging to a given solute were extracted by nonlinear regression, including: the fraction of exchangeable protons, P, the chemical-shift difference between water protons and hydroxyl protons, deltaomega, the intrinsic spin-spin relaxation time, T2, and the chemical exchange rate, k. These solute-specific parameters are related, respectively, to the concentration, identity, mobility and exchange life-time of the hydroxyl site. At 298 K, values of deltaomega, T2 and k were found to be of the order of 1 ppm, 100 ms and 1000 s(-1), respectively. Effects of molecular size, conformation and solute concentration were investigated. The exchange mechanism was characterised by Eyring activation enthalpies and entropies with values in the ranges 50-70 kJ mol(-1) and -10 to 60 J K(-1)mol(-1), respectively.     

Cycloartane glycosides from Astragalus gombo

Six new cycloartane-type triterpene glycosides named 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-xylopyranosyl]-3β,16β,23(R),24(R),25-pentahydroxycycloartane (1), 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-xylopyranosyl]-3β,16β,23(R),24(R)-tetrahydroxy-25-dehydrocycloartane (2), 3-O-[β-d-xylopyranosyl]-6α-acetoxy-23α-methoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (3), 3-O-[β-d-xylopyranosyl]-6α-acetoxy-23α-butoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (4), 3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl]-6α-acetoxy-23α-methoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (5), 3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl]-23α-methoxy-16β,23(R)-epoxy-4,25,26,27-tetranorcycloartane (6), in addition to three known secondary metabolites consisting of another cycloartane triterpene glycoside and two flavonol glycosides, were isolated from the aerial parts of Astragalus gombo Coss. & Dur. (Fabaceae). The structures of the isolated compounds were established by spectroscopic methods, including 1D and 2D-NMR, mass spectrometry and comparison with literature data.     

Two new quinic acid derivatives and one new lignan glycoside from Erycibe obtusifolia

Three new compounds, 4-{erythro-2-[3-(4-hydroxyl-3-methoxyphenyl)-3-O-β-d-glucopyranosyl-propan-1-ol]}-O-medioresinol (1), (7⿳E,9⿳E,1⿳R*,3⿳S*,5⿳R*,6⿳S*)-5-O-caffeoyl-3-O-dihydrophaseicoylquinic acid (2), and (7⿳E,9⿳E,1⿳R*,3⿳S*,5⿳R*,6⿳S*)-5-O-caffeoyl-4-O-dihydrophaseicoylquinic acid (3), were isolated from Chinese folk herb Erycibe obtusifolia together with six known compounds (4⿿9). Their structures were elucidated on the basis of comparisons of literatures and extensive spectroscopic analysis, including UV, IR, HRMS, and 1D and 2D NMR techniques. Further, the cytotoxicities of these compounds were evaluated against five cell lines (HCT-8, Bel-7402, BGC-823, A549, and A2780), but they were inactive against these tumor cell lines (IC₅₀ > 10 μmol/L).