Difference in the biological effects of <Emphasis Type="Italic">Clostridium difficile</Emphasis> toxin B in proliferating and non-proliferating cells

Toxin A (TcdA) and toxin B (TcdB) from Clostridium difficile are the causative agents of the C. difficile-associated diarrhea (CDAD) and its severe form, the pseudomembranous colitis. TcdA and TcdB both glucosylate and thereby inactivate low molecular weight GTP-binding proteins of the Rho, Rac, and Cdc42 subfamilies. In cultured cell lines, TcdB induces actin re-organization and bi-nucleation (“cytopathic effects”) and cell death (“cytotoxic effects”). In this study, the role of cell cycle progression in the cytopathic and the cytotoxic effects of TcdB is evaluated by a differential analysis of these effects in proliferating and non-proliferating cells. Density-synchronized murine fibroblasts and confluent HT29 colonocytes are exploited as cell culture models for non-proliferating cells. Cell death is analyzed in terms of a loss of cell viability, phosphatidylserine exposure, and DNA fragmentation. In proliferating cells, TcdB blocks cell proliferation and induces apoptotic cell death. In contrast, TcdB induces non-apoptotic cell death in non-proliferating cells. TcdB-induced cell rounding turns out to be independent of cell cycle progression. Cell cycle progression is an important determinant in the biological effects of TcdB. With respect to the pathology of CDAD, this study leads to the new hypothesis that necrotic cell death of terminally differentiated colonocytes and inhibition of epithelial renewal of the colon contribute to the pathogenesis of CDAD.     

A new <Emphasis Type="Italic">Erythrina</Emphasis> alkaloid from <Emphasis Type="Italic">Erythrina herbacea</Emphasis>

A new Erythrina alkaloid, 10-hydroxy-11-oxoerysotrine (1), has been isolated from the flowers of Erythrina herbacea together with five known compounds: erytharbine (2), 10,11-dioxoerysotrine (3), erythrartine (4), erysotramidine (5) and erysotrine-N-oxide (6). The structure of the new compound was elucidated on the basis of its spectral data, including 2-D NMR and mass (MS) spectra. The new compound is a rare C-10 oxygenated Erythrina alkaloid. The antioxidant activities of the isolated compounds 1–6 were evaluated by scavenging with peroxynitrite.     

<Emphasis Type="Italic">ent</Emphasis>-Abietane diterpenoids from <Emphasis Type="Italic">Isodon xerophilus</Emphasis>

Three new ent-abietanoids, named xerophilusins XIV–XVI, and four known analogues, as well as four known chemical constituents were isolated from the leaves of Isodon xerophilus. Their structures were elucidated by extensive spectroscopic studies, and comparison with literature data. In addition, the cytotoxic activity of the ent-abietanoids against chronic myelogenous leukemia (K562), stomach adenocarcinoma (MKN45), and hepatocellular carcinoma (HepG2) human cell lines was investigated and no activities were observed.     

Identification of medicinal <Emphasis Type="Italic">Dendrobium</Emphasis> species by phylogenetic analyses using <Emphasis Type="Italic">matK</Emphasis> and <Emphasis Type="Italic">rbcL</Emphasis> sequences

Species identification of five Dendrobium plants was conducted using phylogenetic analysis and the validity of the method was verified. Some Dendrobium plants (Orchidaceae) have been used as herbal medicines but the difficulty in identifying their botanical origin by traditional methods prevented their full modern utilization. Based on the emerging field of molecular systematics as a powerful classification tool, a phylogenetic analysis was conducted using sequences of two plastid genes, the maturase-coding gene (matK) and the large subunit of ribulose 1,5-bisphosphate carboxylase-coding gene (rbcL), as DNA barcodes for species identification of Dendrobium plants. We investigated five medicinal Dendrobium species, Dendrobium fimbriatum, D. moniliforme, D. nobile, D. pulchellum, and D. tosaense. The phylogenetic trees constructed from matK data successfully distinguished each species from each other. On the other hand, rbcL, as a single-locus barcode, offered less species discriminating power than matK, possibly due to its being present with little variation. When results using matK sequences of D. officinale that was deposited in the DNA database were combined, D. officinale and D. tosaense showed a close genetic relationship, which brought us closer to resolving the question of their taxonomic identity. Identification of the plant source as well as the uniformity of the chemical components is critical for the quality control of herbal medicines and it is important that the processed materials be validated. The methods presented here could be applied to the analysis of processed Dendrobium plants and be a promising tool for the identification of botanical origins of crude drugs.     

<Emphasis Type="Italic">In Vitro</Emphasis> hepatoprotective compounds from <Emphasis Type="Italic">Suaeda glauca</Emphasis>

Bioassay-guided fractionation of the MeOH extract of Suaeda glauca yielded four phenolic compounds, methyl 3,5-di-O-caffeoyl quinate (1) and 3,5-di-O-caffeoyl quinic acid (2), isorhamnetin 3-O-beta-D-galactoside (3), and quercetin 3-O-beta-D-galactoside (4). Compounds 1 and 2 were hepatoprotective against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells with the EC(50) values of 72.7+/-6.2 and 117.2+/-10.5 microM, respectively. Silybin as a positive control showed an EC(50) value of 82.4+/-4.1 microM.     

MDMA induces <Emphasis Type="Italic">Per1</Emphasis>, <Emphasis Type="Italic">Per2</Emphasis> and <Emphasis Type="Italic">c-fos</Emphasis> gene expression in rat suprachiasmatic nuclei

Rationale  

±3,4-Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is a psychoactive drug that has marked effects on the serotonergic system. Serotonergic agonists are known to interact with the circadian pacemaker located in the suprachiasmatic nuclei (SCN).     

Biological activity of <Emphasis Type="Italic">Entada phaseoloides</Emphasis> and <Emphasis Type="Italic">Entada rheedei</Emphasis>

The aim of our study is to find functional compounds from natural resources. We focus on plants grown in tropical areas, especially Madagascar and Thailand, because they have unique flora and are expected to contain interesting compounds. We review the functional compounds of the seed kernels of Entada phaseoloides and E. rheedei and their biological activities such as anti-proliferation and melanogenesis inhibitory properties, etc.     

<Emphasis Type="Italic">In Vitro</Emphasis> antioxidant and anti-inflammatory activities of Jaceosidin from <Emphasis Type="Italic">Artemisia princeps</Emphasis> Pampanini <Emphasis Type="Italic">cv.</Emphasis> Sajabal

Oxidized low-density lipoprotein (oxLDL) plays a key role in the inflammatory processes of atherosclerosis. Jaceosidin isolated from the methanolic extracts of the aerial parts of Artemisia princeps Pampanini cv. Sajabal was tested for antioxidant and anti-inflammatory activities. Jaceosidin inhibited the Cu²⁺-mediated LDL oxidation with IC₅₀ values of 10.2 μM in the thiobarbituric acid-reactive substances (TBARS) assay as well as the macrophage-mediated LDL oxidation. The antioxidant activities of jaceosidin were exhibited in the conjugated diene production, relative electrophoretic mobility, and apoB-100 fragmentation on copper-mediated LDL oxidation. Jaceosidin also inhibited the generation of reactive oxygen species (ROS) concerning in regulation of NF-κB signaling. And jaceosidin inhibited nuclear factor-kappa B (NF-κB) activity, nitric oxide (NO) production, and suppressed expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.     

<Emphasis Type="Italic">Perilla frutescens</Emphasis> var. <Emphasis Type="Italic">frutescens</Emphasis> in northern Laos

Twenty-eight samples of mericarps of Perilla frutescens var. frutescens were collected through fieldwork performed in Phongsali and Xieng Khouang provinces in northern Laos. No perilla samples were collected from Savannakhet province in the south although more than 20 sites were investigated. Perilla plants are mostly grown mixed with dry-paddy rice by slash-and-burn cultivation in Laos. The most popular local name for perilla mericarps in the area was “Ma Nga Chan”. Weight of 1,000 grains and hardness of the mericarps were measured, and all mericarps were found to be large (weight of 1,000 grains around 2 g) and soft (limit load weight under 300 g), which were preferred for culinary use in Laos. The composition of the essential oils obtained from the herbaceous plants raised from the mericarps was divided into five types, perillaketone, elemicine plus myristicine, shisofuran, piperitenon, and myristicine, and GC–MS analysis of these Laotian perilla samples showed that they were similar to those of corresponding types of known Japanese perilla strains. One of the shisofuran-type perilla contained large amounts of putative α-naginatene, which is likely to be an intermediate of the biosynthesis of naginataketone. The farmers' indifference to the oil type of the leaf seems to leave Laotian perilla as a good genetic resource for studies of the biosynthesis of oil compounds.     

Biologically active <Emphasis Type="Italic">C</Emphasis>-alkylated flavonoids from <Emphasis Type="Italic">Dodonaea viscosa</Emphasis>

A new C-alkylated flavonoid (5,7-dihydroxy-3′-(4″-acetoxy-3″-methylbutyl)-3,6,4′-trimethoxyflavone (1), along with two known C-alkylated flavonoids (5,7-dihydroxy-3′-(3-hydroxymethylbutyl)-3,6,4′-trimethoxyflavone (2), 5,7,4′-trihydroxy-3′-(3-hyroxymethylbutyl)-3,6-dimethoxyflavone (3) and two new source C-alkylated flavonoids (5,7-dihydroxy-3′-(2-hydroxy-3-methyl-3-butenyl)-3,6,4′-trimethoxyflavone (4), 5,7,4′-trihydroxy-3,6-dimethoxy-3′-isoprenyl-flavone (5) were isolated from the aerial parts of Dodonaea viscosa. The structures of all compounds were established on the basis of 1D and 2D NMR spectroscopy and mass spectrometry. The isolated compounds were evaluated for their inhibitory effect on urease and α-chymotrypsin enzyme. All the compounds (1–5) exhibited mild inhibition against urease but remained recessive in case of α-chymotrypsin.     

Synthesis and evaluation of <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dialkyl substituted chalcones as anti-cancer agents

Several new N,N-dialkyl substituted chalcones (chalconoids or benzylideneacetophenones) have been synthesized via the condensation of corresponding N,N-dialkylbenzaldehyde with various aryl methyl ketones. All the chalcones have been synthesized from readily available and cheap starting materials under environmentally benign conditions in very high yields without work up and column chromatographic purification. Synthesized compounds have been tested for their biological activity against pathogenic microorganisms such as Escherichia coli, Bacillus subtilis, and Mycobacterium smegmatis. Anti-cancer activity of these compounds has also been tested against multiple myeloma (RPMI-8226) and human mammary adenocarcinoma (MCF-7) cell lines. The most hydrophilic molecules 23 and 24 showed very good anti-cancer activity against MCF-7 cell lines at low micro-molar concentrations. All the compounds have also been evaluated for their activity against Beta-secretase 1 enzyme. One of the synthesized compounds showed Beta-secretase 1 enzyme inhibition activity at micro-molar concentration.     

<Emphasis Type="Italic">NAT2</Emphasis>,<Emphasis Type="Italic"> CYP2C9</Emphasis>,<Emphasis Type="Italic"> CYP2C19</Emphasis>, and<Emphasis Type="Italic"> CYP2E1</Emphasis> genetic polymorphisms in anti-TB drug-induced maculopapular eruption

Purpose  

It has been suggested that drug-metabolizing enzymes might play important roles in the development of anti-tuberculosis drug (ATD)-induced maculopapular eruption (MPE), as in ATD-induced hepatitis. We investigated the associations between the genetic polymorphisms of drug-metabolizing enzymes and ATD-induced MPE.     

Novel cycloartane-type triterpenoid from the fruits of <Emphasis Type="Italic">Nandina</Emphasis><Emphasis Type="Italic">domestica</Emphasis>

A novel cycloartane-type triterpenoid was isolated from the fruits of Nandina domestica (Berberidaceae). The structure was characterized as 24-methylene-3-oxocycloartane 13-carboxylic acid on the basis of NMR spectroscopic data.     

Demographic responses of <Emphasis Type="Italic">Daphnia magna</Emphasis> fed transgenic <Emphasis Type="Italic">Bt</Emphasis>-maize

The food/feed quality of a variety of genetically modified (GM) maize expressing Cry1Ab Bt-toxin was tested over the life-cycle of Daphnia magna, an arthropod commonly used as model organism in ecotoxicological studies. Demographic responses were compared between animals fed GM or unmodified (UM) near isogenic maize, with and without the addition of predator smell. Age-specific data on survival and birth rates were integrated and analysed using life tables and Leslie matrices. Survival, fecundity and population growth rate (PGR) data generally disfavoured transgenic Bt-maize as feed for D. magna compared to animals fed the unmodified (UM) near isogenic line of maize. Decomposition of age-specific effects revealed that the most important contributions to a reduced PGR in the GM-fed group came from both fecundity and survival differences early in life. We conclude that juvenile and young adult stages are the most sensitive experimental units and should be prioritized in future research. These stages are often omitted in toxicological/ecotoxicological studies and in feeding trials.     

Genetic and chemical comparison of Boi (<Emphasis Type="Italic">Sinomeni Caulis</Emphasis><Emphasis Type="Italic">et Rhizoma</Emphasis>) and Seifuto (<Emphasis Type="Italic">Caulis Sinomenii</Emphasis>)

Boi and its original plant Sinomenium acutum from Japan were compared with Seifuto and its botanical origins from China in terms of their internal transcribed spacer (ITS) sequences and major chemical components. Boi, Seifuto, and their botanical origins overall showed seven variable sites in the ITS sequence and six genotypes. Japanese S. acutum and Boi had one nucleotide variation at position 593 to show two genotypes (J1 and J2) and their heterozygote (J3). Seifuto samples and their botanical origins, S. acutum and S. acutum var. cinereum from China, showed three genotypes (C1, C2, and C3), which did not agree with the botanical classification, indicating that they cannot be distinguished according to their ITS sequences. All Seifuto samples from Henan market showed the same ITS genotype (C1). The Japanese and Chinese genotypes differed in the nucleotide position 424, which can be used to distinguish the country of origin of these materials. In the HPLC analysis of six major components, sinomenine (1), magnoflorine (2), menisperine (3), 6-O-methyllaudanosoline glucoside (4), liriodendrin (5), and menisdaurin (6), all were detected in Boi, whereas five (all except for menisdaurin) were detected in Seifuto. The main component in the rhizome of Seifuto was sinomenine, whereas magnoflorine was the main component in the rhizome and the climbing stem of Boi. The content of sinomenine in Seifuto was almost twice that in Boi. Although the individual content of alkaloids 1–4 differed between Boi and Seifuto, the total contents of these alkaloids were comparable between them both in the climbing stem and rhizome.     

Antioxidant <Emphasis Type="Italic">C</Emphasis>-glycosylflavones of <Emphasis Type="Italic">Drymaria cordata</Emphasis> (Linn.) Willd

A new C-glycosylflavone, drymaritin E (6-C-(3-keto-β-digitoxopyranosyl)-4′-O-(β-d-glucopyranosyl)-7-methoxyl-5,4′-dihydroxylflavone) 1 was isolated from the oily upper phase (SU) of the MeOH extract from aerial parts of Drymaria cordata together with two known compounds (cassiaoccidentalin A 2 and anemonin 3) and an inseparable mixture of two known C-glycosylflavones 5,4′-dihydroxy-7-methoxyflavone-6-C-(2′′-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside 4a and 5,7,3′,4′-tetrahydroxyflavone-6-C-(2′′-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside 4b. The alkaline hydrolysis of 3 led to a new hemisynthetic derivative, sodium anemonate (sodium 2-((1’E) 2′-sodium-carboxylate-vinyl)-5-oxo-cyclohex-1-ene carboxylate) 3a. The chemical structures were determined by spectroscopic methods (¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMBC, HSQC, and NOESY) and mass spectrometry (ESI–MS). C-glycosylflavones had significant free radical-scavenging activities on the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). However, SU and compounds 3 and 3a exhibited no activity. In particular, compound 1 exhibited a concentration-dependent radical scavenging activity on DPPH with EC₅₀ of 31.43 µg/mL.     

Inhibition of DNA topoisomerases I and II and cytotoxicity of compounds from <Emphasis Type="Italic">Ulmus davidiana</Emphasis> var. <Emphasis Type="Italic">japonica</Emphasis>

Twenty five compounds including ten triterpenes (1–3, 5–11), six flavonoids (12–15, 24, 25), five lignans (17, 18, 21–23), two butenyl clohexnone glycosides (19–20), one fructofuranoside (16) and one fatty acid (4) were isolated from the roots of Ulmus davidiana var. japonica. The structures of those compounds were identified by comparing their physicochemical and spectral data with those of published in literatures. All the compounds were evaluated for DNA topoisomerase inhibitory activities and cytotoxicities. Among the purified compounds, 4 and 19 showed more potent inhibitory acitivities (IC₅₀: 39 and 19 μM, respectively) than camptothecin, as the positive control (IC₅₀: 46 μM) against topoisomerase I. Compounds, 4, 10, 12, 19, 24 and 25 showed strong inhibitory activities toward DNA topoisomerase II (IC₅₀: 0.1, 0.52, 0.47, 0.42, 0.17 μM and 17 nM, respectively), which were more potent than that of etoposide as positive control (IC₅₀: 20 μM). In A549 cell line, 5 and 6 showed cytotoxicities (IC₅₀: 4 μM and 3 μM, respectively, with IC₅₀ of camptothecin as positive control: 10.3 μM). In the HepG2 cell line, 3, 5 and 7 showed cytotoxicity (IC₅₀: 4, 3 and 4 μM, respectively, with IC₅₀ of camptothecin: 0.3 μM). Compounds 6, 12 and 23 showed cytotoxicities in the HT-29 cell line (IC₅₀: 19, 19 and 15 μM, respectively, with IC₅₀ of camptothecin: 2 μM).