Fatty acids of Rhodobryum ontariense (Bryaceae)

The chemical composition of Rhodobryum ontariense (Kindb.) Kindb. has not been previously investigated. Fatty acids of this moss were analysed qualitatively and quantitatively with an aim to identify its corresponding pattern. A total of eight fatty acids were identified including two acetylenic ones: 9,12,15-octadecatrien-6-ynoic acid (42.26%), α-linolenic acid (20.32%), palmitic acid (14.31%), 9,12-octadecadienoic-6-ynoic acid (13.31%), linoleic acid (5.25%), oleic acid (2.47%), stearic acid (1.14%) and γ-linolenic acid (0.92%). To our knowledge, this is the first record of acetylenic fatty acids in the genus Rhodobryum. In general, acetylenic fatty acids vary considerably among different moss groups and have been used as a chemotaxonomic character in bryophyte classifications. Other species of Rhodobryum from Asia have been traditionally used in ethno medicine by indigenous cultures. Two fatty acids of those reported here, 9,12,15-octadecatrien-6-ynoic and α-linolenic acid, have known cardio protective activity, which supports respective claims of traditional herbal use of these mosses.     

Heavy metal content of a medicinal moss tea for hypertension

The content of various heavy metals (arsenic, cadmium, chromium, copper, iron, lead, mercury, nickel, manganese and zinc) in the moss species Rhodobryum ontariense (Kindb.) Kindb. and its tea are presented in this study. Pursuant to the use of this tea in traditional Chinese medicine for hypertension, the aim of this study was to examine its safety in regard to the metals. All heavy metals were determined by adequate EPA methods. The concentrations of all metals for daily intake in its tea were below the safety levels for human consumption. These results indicate the importance of manganese in R. ontariense tea traditionally used for hypertension and other heart disorders.     

Cloning and functional characterization of a fructan 1-exohydrolase (1-FEH) in edible burdock (<Emphasis Type="Italic">Arctium lappa</Emphasis>L.)

Background  

We have previously reported on the variation of total fructooligosaccharides (FOS), total inulooligosaccharides (IOS) and inulin in the roots of burdock stored at different temperatures. During storage at 0°C, an increase of FOS as a result of the hydrolysis of inulin was observed. Moreover, we suggested that an increase of IOS would likely be due to the synthesis of the IOS by fructosyltransfer from 1-kestose to accumulated fructose and elongated fructose oligomers which can act as acceptors for fructan:fructan 1-fructosyltransferase (1-FFT). However, enzymes such as inulinase or fructan 1-exohydorolase (1-FEH) involved in inulin degradation in burdock roots are still not known. Here, we report the isolation and functional analysis of a gene encoding burdock 1-FEH.     

Studies on the amide compounds ofMirabilis. Jalapa. L

Mirabilis himalaica(Edgew.)Heinerl Var. Chinensis Heimerl belonging to the genus Mirabilis are used in chinese medicine as a remedy for various diseases[1].Its chemical constituents,however, have not been reported so far. we have carried out a detailed chemical investigatigation of the seeds and have isolated two new amides along with three known compounds. The known compounds were identified by comparing their spectral data with those of authentic samples or with those reported in literature as daucosterol[2], bsitoserol[2], boeravinone E[3], in the present note, the structural elucidation of two new amides is reported.     

Hypoglycemic constituents of Gynura divaricata subsp. formosana

Gynura divaricata Kitam. subsp. formosana is a folk medicine used as a hypoglycemic agent for diabetes patients in Taiwan. Guided by the hexose transport assay, the hypoglycemic constituents of the aerial part of this plant were disclosed through chromatographic methods. They are fructooligosaccharides, including beta-D-fructofuranose, sucrose, 1-kestose, nystose, and 1(F)-beta-fructofuranosylnystose. The hexose transport assay indicated that nystose was the most potent among these compounds, showing a 46.7% difference from pinitol in the stimulation index at a concentration of 0.5 mg/mL.     

Bioactive pentacyclic triterpenes from the stems of Combretum laxum

Two new triterpene glucosides, beta-D-glucopyranosyl 2alpha,3beta,24-trihydroxyolean- 12-en-28-oate and beta-D-glucopyranosyl 2alpha,3beta,23,24-tetrahydroxyurs-12-en-28-oate, in addition to nine known compounds belonging to three different triterpene classes (oleanane-, ursane- and lupane-type) have been isolated from the stems of a specimen of Combretum laxum growing in the "Pantanal" of the central-western region of Brazil. Among the known triterpenes, beta-D-glucopyranosyl 2alpha,3beta,6beta-trihydroxyolean-12-en-28-oate is reported for the first time in the Combretaceae, while bellericoside and asiatic acid are described for the first time in the genus Combretum. The structures of the isolated compounds have been established on the basis of spectral techniques (1D-, 2D-NMR and MS). Their in vitro antifungal activities against standard strains of Candida albicans, C. krusei and Cryptococcus neoformans were also evaluated in this work.     

高效液相色谱-蒸发光散射法测定食品中的单糖、双糖、低聚果糖和糖醇

建立了食品中常用的木糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖、蔗果三糖、蔗果四糖、蔗果五糖、赤藓糖醇、木糖醇、甘露糖醇、麦芽糖醇等13种单糖、双糖、低聚果糖和糖醇的高效液相色谱同时分离检测的方法。该法采用NH₂色谱柱,以乙腈-水为流动相梯度洗脱,蒸发光散射检测器检测;13种糖在0.1~5 g/L内均具有良好的线性关系,检出限均在0.1 g/L以下,精密度(RSD)为2.69%~7.21%,回收率为96.1%~105.2%,结果较为理想。将该法用于实际样品检测,结果显示食品标签明示和实际成分相差较大。     

Experimental evidence for the existence of non-exo-anomeric conformations in branched oligosaccharides: NMR analysis of the structure and dynamics of aminoglycosides of the neomycin family

It is commonly known that the exo-anomeric effect is a major factor governing the conformational behavior of naturally occurring oligosaccharides. Conformational flexibility in these molecules mainly concerns the aglycon psi angle since phi is restricted by this stereo-electronic effect. In fact, to the best of our knowledge no case of a natural glycoside adopting a non-exo-anomeric conformation in solution has yet been reported. With respect to the flexibility among naturally occurring carbohydrates, branched type oligosaccharides including sugar residues glycosidated at contiguous positions (such as blood type carbohydrate antigens Lewis X) have been considered as the paradigm of rigid saccharides--the rigidity being enhanced by van der Waals interactions. Herein, we demonstrate unambiguously that both common beliefs are not to be generalized. For example in neomycin B, a branched oligosaccharide antibiotic, a large number of non-exo-anomeric conformations was detected in solution for the first time in naturally occurring sugars. This unusual behavior is attributed to branching. Here, polar contacts between non-vicinal sugar units lead to an enhanced flexibility of the ribose glycosidic torsion phi. The influence of sugar flexibility on RNA recognition will also be discussed.     

Separation and identification of enzymatic sucrose hydrolysis products by high-performance anion-exchange chromatography with pulsed amperometric detection

An accurate carbohydrate analysis method, namely high-performance anion-exchange chromatography with pulsed amperometric detection was successfully applied to the study of sucrose hydrolysis under enzymatic (baker's yeast invertase) conditions. The hydrolysis was monitored by determining sucrose degradation and the corresponding formation of D-glucose, D-fructose and five intermediate fructans using a CarboPac PA-100 (Dionex) analytical anion-exchange column. Highly reproducible results were obtained. The unknown fructans were collected from a semi-preparative CarboPac PA-100 (Dionex) column, neutralized and then desalted on a column containing mixed bed resin AG 501-X8 (D) before identification of the chemical structure. This procedure permitted us to obtain about 20 microg of pure product which is not enough for NMR analysis. Detailed GC-MS analytical data of the methylated compounds indicated that these oligosaccharides were beta-D-Fru-(2 --> 1)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (1-kestose), beta-D-Fru-(2 --> 6)-alpha-D-glucopyranoside (6-beta fructofuranosylglucose), beta-D-Fru-(2 --> 1)-beta-D-fructofuranoside (inulobiose), beta-D-Fru-(2 --> 6)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (6-kestose) and beta-D-Fru-(2 --> 6)-alpha-D-Glc-(1 --> 2)-beta-D-fructofuranoside (neokestose) coeluating with a disaccharide.     

Synthesis and structure of novel conformationally constrained 1',2'-azetidine-fused bicyclic pyrimidine nucleosides: their incorporation into oligo-DNAs and thermal stability of the heteroduplexes

[structures: see text] The synthesis of novel 1',2'-aminomethylene bridged (6-aza-2-oxabicyclo[3.2.0]heptane) "azetidine" pyrimidine nucleosides and their transformations to the corresponding phosphoramidite building blocks (20, 39, and 42) for automated solid-phase oligonucleotide synthesis is reported. The novel bicyclonucleoside "azetidine" monomers were synthesized by two different strategies starting from the known sugar intermediate 6-O-benzyl-1,2:3,4-bis-O-isopropylidene-D-psicofuranose. Conformational analysis performed by molecular modeling (ab initio and MD simulations) and NMR showed that the azetidine-fused furanose sugar is locked in a North-East conformation with pseudorotational phase angle (P) in the range of 44.5-53.8 degrees and sugar puckering amplitude (phi(m)) of 29.3-32.6 degrees for the azetidine-modified T, U, C, and 5-Me-C nucleosides. Thermal denaturation studies of azetidine-modified oligo-DNA/RNA heteroduplexes show that the azetidine-fused nucleosides display improved binding affinities when compared to that of previously synthesized North-East sugar constrained oxetane fused analogues.     

Marine gradients of halogens in moss studies by epithermal neutron activation analysis

INAA is known to be a powerful technique for the simultaneous determination of chlorine, bromine and iodine. In this paper INAA using epithermal neutrons is shown to be particularly useful to elucidate marine gradients of these elements. Examples are from a transect study in northern Norway where samples of the feather moss Hylocomium splendens were collected at distances of 0-300 km from the coastline. All three elements decrease exponentially as a function of distance from the ocean in the moss samples, strongly indicating that the atmospheric supply from the marine environment is the predominant source of these elements to the terrestrial ecosystem. It is suggested that environmental studies of halogens in general and iodine in particular is a promising future area of application for INAA, when employing epithermal neutrons. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phenolic constituents from the rhizomes of Dryopteris crassirhizoma

A new phenolic glycoside, dryopteroside (1), was isolated from the rhizomes of Dryopteris crassirhizoma (Dryopteridaceae), together with five known compounds, 4beta-carboxymethyl-(-)-epicatechin (2), isobiflorin (3), biflorin (4), 1-beta-D-glucopyranosyloxy-3-methoxy-5-hydroxybenzene (5) and (+)-catechin-6-C-beta-D-glucopyranoside (6). The new compound was elucidated to be 1-butanoyl-3-C-beta-D-glucopyranosyl-5-methyl-phloroglucinyl-6-O-beta-D-glucopyranoside (1) by chemical and various spectroscopic analyses. The known compounds 2-6 were first reported from the genus Dryopteris.     

Structure elucidation and synthesis of lycoposerramine-B, a novel oxime-containing Lycopodium alkaloid from Lycopodium serratum Thunb

A new alkaloid, lycoposerramine-B (1), containing an oxime function, was isolated from the club moss Lycopodium serratum Thunb. The structure of 1 was elucidated by spectroscopic analysis, including J-resolved HMBC spectroscopy, and confirmed by its synthesis from the known alkaloid, serratinine (3).     

Development of a sugar-binding residue prediction system from protein sequences using support vector machine

Several methods have been proposed for protein–sugar binding site prediction using machine learning algorithms. However, they are not effective to learn various properties of binding site residues caused by various interactions between proteins and sugars. In this study, we classified sugars into acidic and nonacidic sugars and showed that their binding sites have different amino acid occurrence frequencies. By using this result, we developed sugar-binding residue predictors dedicated to the two classes of sugars: an acid sugar binding predictor and a nonacidic sugar binding predictor. We also developed a combination predictor which combines the results of the two predictors. We showed that when a sugar is known to be an acidic sugar, the acidic sugar binding predictor achieves the best performance, and showed that when a sugar is known to be a nonacidic sugar or is not known to be either of the two classes, the combination predictor achieves the best performance. Our method uses only amino acid sequences for prediction. Support vector machine was used as a machine learning algorithm and the position-specific scoring matrix created by the position-specific iterative basic local alignment search tool was used as the feature vector. We evaluated the performance of the predictors using five-fold cross-validation. We have launched our system, as an open source freeware tool on the GitHub repository (https://doi.org/10.5281/zenodo.61513).     

Compilation of secondary metabolites from Bidens pilosa L

Bidens pilosa L. is a cosmopolitan annual herb, known for its traditional use in treating various diseases and thus much studied for the biological activity of its extracts, fractions and isolated compounds. Polyacetylenes and flavonoids, typical metabolite classes in the Bidens genus, predominate in the phytochemistry of B. pilosa. These classes of compounds have great taxonomic significance. In the Asteraceae family, the acetylene moiety is widely distributed in the Heliantheae tribe and some representatives, such as 1-phenylhepta-1,3,5-triyne, are noted for their biological activity and strong long-wave UV radiation absorbance. The flavonoids, specifically aurones and chalcones, have been reported as good sub-tribal level markers. Natural products from several other classes have also been isolated from different parts of B. pilosa. This review summarizes the available information on the 198 natural products isolated to date from B. pilosa.     

Detection of added beet or cane sugar in maple syrup by the site-specific deuterium nuclear magnetic resonance (SNIF-NMR) method: collaborative study

Results of a collaborative study are reported for the detection of added beet or cane sugar in maple syrup by the site-specific natural isotope fractionation-nuclear magnetic resonance (SNIF-NMR) method. The method is based on the fact that the deuterium content at specific positions of the sugar molecules is different in maple syrup from that in beet or cane sugar. The syrup is diluted with pure water and fermented; the alcohol is distilled with a quantitative yield and analyzed with a high-field NMR spectrometer fitted with a deuterium probe and fluorine lock. The proportion of ethanol molecules monodeuterated at the methyl site is recorded. This parameter (D/H)I is decreased when beet sugar is added and increased when cane sugar is added to the maple syrup. The precision of the method for measuring (D/H)I was found to be in good agreement with the values already published for the application of this method to fruit juice concentrates (AOAC Official Method 995.17). An excellent correlation was found between the percentage of added beet sugar and the (D/H)I isotopic ratio measured in this collaborative study. Consequently, all samples in which exogenous sugars were added were found to have a (D/H)I isotopic ratio significantly different from the normal value for an authentic maple syrup. By extension of what is known about plants having the C4 cycle, the method can be applied to corn sweeteners as well as to cane sugar. One limitation of the method is its reduced sensitivity when applied to specific blends of beet and cane sugars or corn sweeteners. In such case, the C13 ratio measurement (see AOAC Official Method 984.23, Corn Syrup and Cane Sugar in Maple Syrup) may be used in conjunction.     

Effects of eleven flavonoids from the osteoprotective fraction of Drynaria fortunei (KUNZE) J. SM. on osteoblastic proliferation using an osteoblast-like cell line

Drynaria fortunei (KUNZE) J. SM. (DFE) is one of the most frequently used traditional Chinese medicines prescribed for the treatment of osteoporosis in China. The present study was designed to investigate the osteoprotective constituents from Drynaria fortunei. The 60% ethanol extract of the rhizome of D. fortunei (DFE) was chromatographed on a D-101 macroporous resin column (psi 25x150 cm); three fractions (DFA eluted with water, DFB eluted with 30% and 50% ethanol, and DFC eluted with 95% ethanol) were obtained and their osteoprotective activity as examined both in vivo and in vitro. DFB showed significant activity on both the proliferation of UMR106 cells and promoting bone mineral density (BMD) in ovariectomized (OVX) mice. A bioactivity-guided method led to the isolation of 11 flavonoids from this fraction (DFB) with antiosteoporotic activity, including two new compounds, kaempferol 3-O-beta-D-glucopyranoside-7-O-alpha-L-arabinofuranoside (1) and (R)-5,7,3',5'-tetrahydroxy-flavanone 7-O-neohesperidoside (2), along with nine known ones: three flavanones (3-5), one flavone (7), one flavonol (6), two chromones (8, 10), maltol glucoside (9), and (-)-epicatechin (11). Compounds 4-11 are reported for the first time from this genus. We investigated the proliferative effects of the 11 compounds in the UMR106 osteoblastic cell line in vitro. All compounds exhibited the proliferative activity in the UMR106 cells at most of the concentrations tested. Most compounds are reported for the first time from the Drynaria genus and this was the first study of their proliferative activity in osteoblast-like cells. The main peaks in the HPLC fingerprint of the active fraction (DFB) were also identified.     

Highly redispersible sugar beet nanofibers as reinforcement in bionanocomposites

A simple method for preparing redispersible nanofibers from sugar beet residue and their use as a well-dispersed reinforcement for a polyvinyl alcohol (PVA) matrix is reported. It is known that the redispersion of dried cellulose nanofibers is difficult because of the formation of strong hydrogen bonds between the nanofibers. The results show that the properties of the initial sugar beet nanofiber suspension can be recovered without the use of chemical modification or additives with higher pectin and hemicellulose content. Undried and redispersed nanofibers with and without pectin were used as nanocomposite reinforcement with PVA. The redispersed nanofibers were as good reinforcements as the undried nanofibers. The tensile strength and elastic modulus of the nanocomposites with the redispersed sugar beet nanofibers were as good as those of the nanocomposites with undried nanofibers. Interestingly, the nanofiber dispersion in the PVA matrix was better when sugar beet nanofibers containing pectin and hemicellulose were used as reinforcements.     

First,Highly Stereoselective Synthesis of Neotrehalosamines

ABSTRACT

Among the known non-symmetrical naturally occurring aminotrehaloses possessing antimicrobial activity, the stereoselective synthesis of α, α-linked D-glucosaminyl-D-glucoside as well as of D-glucosaminyl-D-mannoside has been reported.¹ In contrast, the synthesis of the α, β-isomer composed of two 2-amino sugar units occurring in tunicamycin antibiotics 1 has not been studied to the same extent and is not readily obtainable in pure form.     

Two New Pentacyclic Triterpenoids from Centella asiatica

Two new pentacyclic triterpenoids, named centelloside D ( 1 ) and centelloside E ( 9 ), together with the seven known compounds 2 – 8 , were isolated from the whole plants of Centella asiatica. Compound 5 was reported for the first time from this genus. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D ‐ and 2D ‐NMR, and HR‐MS experiments, and by comparison with literature data. Compounds 1 – 4, 6 , and 8 did not show any cytotoxicity against L929 (mouse embryonic fibroblast).