Published by De Gruyter

Volume 62 Issue 3-4

Issue of Zeitschrift für Naturforschung C

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Journal Overview

Open Access June 2, 2014

Chemodiversity of Exudate Flavonoids in Seven Tribes of Cichorioideae and Asteroideae (Asteraceae)

Karin M. Valant-Vetschera, Eckhard Wollenweber

Page range: 155-163

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Abstract

Members of several genera of Asteraceae, belonging to the tribes Mutisieae, Cardueae, Lactuceae (all subfamily Cichorioideae), and of Astereae, Senecioneae, Helenieae and Heliantheae (all subfamily Asteroideae) have been analyzed for chemodiversity of their exudate flavonoid profiles. The majority of structures found were flavones and flavonols, sometimes with 6- and/or 8-substitution, and with a varying degree of oxidation and methylation. Flavanones were observed in exudates of some genera, and, in some cases, also flavonol- and flavone glycosides were detected. This was mostly the case when exudates were poor both in yield and chemical complexity. Structurally diverse profiles are found particularly within Astereae and Heliantheae. The tribes in the subfamily Cichorioideae exhibited less complex flavonoid profiles. Current results are compared to literature data, and botanical information is included on the studied taxa.

Open Access June 2, 2014

Antimicrobial Isoflavonoids from Erythrina crista galli Infected with Phomopsis sp.

Flavia Redko, María L. Clavin, Daniela Weber, Fernando Ranea, Timm Anke, Virginia Martino

Page range: 164-168

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Abstract

The isoflavonoids coumestrol, genistein and daidzein have been isolated and identified by bioassay-guided fractionation from the acetone extract of Erythrina crista galli young twigs infected with Phomopsis sp. These compounds showed antimicrobial activity against Bacillus brevis (MIC values 16.3, 64.8 and 137.8 μm, respectively). This is the first time that coumestrol, besides lutein and n-nonacosane, are reported in this species.

Open Access June 2, 2014

Cytotoxic α-Pyrones from Xylaria hypoxylon

Anja Schüffler, Olov Sterner, Heidrun Anke

Page range: 169-172

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Abstract

Two new α-pyrone derivatives, xylarone (1) and 8,9-dehydroxylarone (2) possessing cytotoxic activities, were isolated from the culture fluid of submerged cultures of the ascomycete Xylaria hypoxylon, strain A27-94. Their structures were elucidated by spectroscopic methods.

Open Access June 2, 2014

Antibacterial Activity of Extract, Fractions and Four Compounds Extracted from Piper solmsianum C. DC. var. solmsianum (Piperaceae)

Marina P. Campos, Valdir Cechinel Filho, Rosi Z. Silva, Rosendo A. Yunes, Franco D. Monache, Alexandre Bella Cruz

Page range: 173-178

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Abstract

Piper solmsianum C. DC. var. solmsianum (Piperaceae) is a shrub commonly found in areas with wet tropical soils. Other Piper species have been used in folk medicine as antitumoral and antiseptic agents. We studied the crude methanolic extract, some organic fractions and compounds isolated from this plant for possible antimicrobial activity against Grampositive and Gram-negative bacteria. The bioautographic assays disclosed three inhibition zones. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined showing excellent activity, particularly against the Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus, Staphylococcus saprophyticus and Streptococcus agalactiae). It appears that the antimicrobial activity of Piper solmsianum is related mainly to the presence of conocarpan and eupomatenoid-5 (neolignans). However another, as yet unidentified, active compound could also be extracted from the plant.

Open Access June 2, 2014

Red Mexican Grapefruit: A Novel Source for Bioactive Limonoids and their Antioxidant Activity

Kranthi K. Mandadi, Guddadarangavvanahally K. Jayaprakasha, Narayan G. Bhat, Bhimanagouda S. Patil

Page range: 179-188

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Abstract

Citrus limonoids have shown to inhibit the growth of cancer in colon, lung, mouth, stomach and breast in animal and cell culture studies. For the first time in the present study, an attempt has been made to isolate antioxidant fractions and five limonoids from red Mexican grapefruit seeds. Defatted seed powder was successively extracted with hexane, ethyl acetate (EtOAc), acetone, methanol (MeOH) and MeOH/water and the extracts were concentrated under vacuum. Radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and total phenolic content were also measured for comparison with the antioxidant capacity in the phosphomolybdenum method for the above extracts. Acetone and MeOH extracts, respectively, showed the highest (85.7%) and lowest (53.3%) radical scavenging activity, at 500 ppm. The total phenolic contents were found to be highest in the acetone extract (15.94%) followed by the MeOH extract (5.92%), ethyl acetate extract (5.54%) and water extract (5.26%). Antioxidant capacity of the extracts as equivalents to ascorbic acid (μmol/g of the extract) was in the order, EtOAc extract > acetone extract > water extract > methanol extract. Furthermore, the EtOAC and acetone extracts were loaded onto silica gel columns to obtain four limonoid aglycons. MeOH fraction was loaded onto a dowex-50 and sepabeads resin column to obtain a limonoid glucoside. The purity of the isolated five compounds was analyzed by HPLC using a C18 column and UV detection at 210 nm. Finally, the structures of the compounds were identified as obacunone, nomilin, limonin, deacetylnomilin (DAN) and limonin-17-β-d-glucopyranoside (LG) using 1 H and 13 C NMR studies.

Open Access June 2, 2014

Antiproliferative Activity of Methylated Analogues of E- and Z-Resveratrol

Venera Cardile, Rosa Chillemi, Laura Lombardo, Sebastiano Sciuto, Carmela Spatafora, Corrado Tringali

Page range: 189-195

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Abstract

The stilbenoids E-resveratrol (E-3,5,4′-trihydroxystilbene, 1), E-3,5,4′-trimethoxystilbene (2), E-3,4,4′-trimethoxystilbene (3) and E-3,4′-dimethoxy-5-hydroxystilbene (4) were converted by photoisomerization to their corresponding Z-isomers 5D8. Compounds 1D8 were subjected to antiproliferative activity bioassays towards a set of four different human cancer cell lines, namely DU-145 (androgen not responsive human prostate tumor), LNCaP (androgen responsive human prostate tumor), M-14 (human melanoma) and KB (human mouth epidermoid carcinoma). The methylated analogues of 1 are more active than the natural lead in the majority of bioassays. The most active compound was Z-3,5,4′-trimethoxystilbene (6), which showed against DU-145 and LNCaP cells GI50 values close to those of the anticancer drug vinorelbine; 6 resulted more active than its E-isomer 2 towards DU-145, LNCaP and especially KB cell lines. A number of methylated Z-isomers displayed a higher activity than their E-isomers, but E-resveratrol (1) was more active than Z-resveratrol (5) towards all the tested cell lines.

Open Access June 2, 2014

Bioactive Phenolic Compounds from Aerial Parts of Plinia glomerata

Claúdia Serafin, Viviane Nart, Angela Malheiros, Márcia Maria de Souza, Luiz Fischer, Giuliano Delle Monache, Franco Delle Monache, Valdir Cechinel Filho

Page range: 196-200

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Abstract

The present work describes the antinociceptive properties and chemical composition of the aerial parts of Plinia glomerata (Myrtaceae). Both of the extracts evaluated, acetonic and methanolic, showed potent antinociceptive action, when analyzed against acetic acid-induced abdominal constrictions in mice, with calculated ID 50 (mg/kg, i. p.) values of 24.8 and 3.3, respectively. Through usual chromatographic techniques with an acetonic extract, the following compounds were obtained: 3,4,3′-trimethoxy flavellagic acid (1), 3,4,3′-trimethoxy flavellagic acid 4′-O-glucoside (3) and quercitrin (4), which were identified based on spectroscopic data. Compounds 1 (ID 50 = 3.9 mg/kg, i. p., or 10.8 μmol/kg) and 3 (ID 50 = 1.3 mg/kg or 2.5 μmol/kg) were notably more active than some well-known analgesic drugs used here for comparison.

Open Access June 2, 2014

Antinociceptive Effects of Tetrahydrophthalimides and Related Compounds

Bianca B. C. Costa, Rogério Corrêa, Marcia M. De Souza, Juliana B. Pretto, Juliana V. Ardenghi, Fátima De Campos-Buzzi, Valdir Cechinel Filho

Page range: 201-206

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Abstract

This paper describes the antinociceptive effects of tetrahydrophthalimides and related compounds in mice. Twenty compounds were obtained by the reaction of cis-1,2,3,6-tetrahydrophthalic anhydride with appropriate amines, dehydration, and addition to the imidic double bond. They were analyzed in the writhing test at 10 mg/kg given intraperitoneally. The most active compound 2-benzyl-5-morpholin-4-yl-hexahydroisoindole-1,3-dione (19) was studied on formalin, capsaicin, glutamate and hot plate models. The antinociceptive activity demonstrated by some studied compounds is promising, and some of them were more active than acetylsalicylic acid and paracetamol used as reference drugs in writhing tests in mice. Compound 19 was about 5-fold more potent than the reference drugs, being also effective by oral route and against the inflammatory response in the formalin test. The results suggest that compound 19 could be used as a model to obtain new and more potent antinociceptive agents. It exhibits an interesting antinociceptive profile, and does not interact with opioid systems.

Open Access June 2, 2014

Inhibitory Effects of Monoterpenes on Seed Germination and Seedling Growth

Saban Kordali, Ahmet Cakir, Sunay Sutay

Page range: 207-214

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Abstract

Monoterpenes, the chemical constituents of essential oils found in plants, are known biologically active compounds. The present study was conducted to investigate the inhibitory effects of 30 monoterpenes including monoterpene hydrocarbons and oxygenated monoterpenes on seed germination and seedling growth of Amaranthus retroflexus, Chenopodium album and Rumex crispus under laboratory conditions. The monoterpenes were applied at contents of 10 and 20 μl for liquid compounds and 10 and 20 μg for solid compounds. The results show that most of the monoterpenes significantly inhibited seed germination and seedling growth of the tested plants. Oxygenated monoterpenes including β-citronellol, nerol and terpinen-4-ol completely inhibited seed germination and seedling growth of all tested plants. Their inhibitory effects were also stronger than that of the herbicide 2,4-D. In general, monoterpenes were less effective against seed germination and seedling growth of C. album as compared with R. crispus and A. retroflexus. Phytotoxic effects of monoterpene hydrocarbons were found to be lower than those of oxygenated monoterpenes. The alcohol derivatives of oxygenated monoterpenes were also found to be more phytotoxic as compared with their acetate derivatives. Based on the present results, it can be concluded that the oxygenated monoterpenes can be used as potential bio-herbicides.

Open Access June 2, 2014

Protective Effect of Curcumin and Chlorophyllin against DNA Mutation Induced by Cyclophosphamide or Benzo[a]pyrene

Marwa A. Ibrahim, Adel M. Elbehairy, Magdy A. Ghoneim, Hassan A. Amer

Page range: 215-222

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Abstract

The current study was carried out to evaluate the potency of curcumin and chlorophyllin as natural antioxidants to reduce the oxidative stress markers induced by cyclophosphamide (CP) and benzo[a]pyrene [B(a)P] which were used as free radical inducers. For this purpose, 126 male albino rats were used. The animals were assigned into 4 main groups: negative control group; oxidant-treated group (subdivided into two subgroups: cyclophosphamide- treated group and benzo[a]pyrene-treated group); curcumin-treated group; and chlorophyllin-treated group. Liver samples were collected after two days post the oxidant inoculation and at the end of the experimental period (10 weeks). These samples were examined for determination of liver microsomal malondialdehyde (MDA), DNA fragmentation, restriction fragment length polymorphism (RFLP) and 8-hydroxy deoxyguanosine (8-OHdG) concentration. Both CP and B(a)P caused increments in DNA fragmentation percentages, liver microsomal MDA, concentration of 8-OHdG and induced point mutation. Treatment of rats with either curcumin or chlorophyllin revealed lower DNA fragmentation percentages, liver microsomal MDA concentration, concentration of 8-OHdG and prevented induction of mutations, i. e., reversed the oxidative stress induced by CP and B(a)P and proved that they were capable of protecting rats against the oxidative damage evoked by these oxidants.

Open Access June 2, 2014

Alkaloids of Crinum x powellii “Album” (Amaryllidaceae) and their Topoisomerase Inhibitory Activity

Jaime Niño, Gina M. Hincapié, Yaned M. Correa, Oscar M. Mosquera

Page range: 223-226

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Abstract

The alkaloids lycorine, 1-O-acetyllycorine and ismine were isolated from the basic dichloromethane- soluble fraction of Crinum x powellii “Album” bulbs. The alkaloid structures were established by physical and spectroscopic analyses, including 1D NMR techniques and GCMS analysis. The three alkaloids are reported for the first time for this hybrid. Additionally, the three alkaloids isolated were tested against a mechanism-based bioassay utilizing genetically engineered mutants of the yeast Saccharomyces cerevisiae strains RAD+, RAD52Y and RS321 where lycorine was the only alkaloid that displayed moderate topoisomerase I inhibitory activity.

Open Access June 2, 2014

Effects of Salicylic Acid on Mushroom Tyrosinase and B16 Melanoma Cells

Sadaaki Tamura, Teruhiko Nitoda, Isao Kubo

Page range: 227-233

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Abstract

Salicylic acid slightly inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by mushroom tyrosinase noncompetitively without being oxidized. In contrast, 4-hydroxybenzoic acid did not inhibit this enzymatic oxidation if a longer reaction time was observed, although it suppressed the initial rate of the oxidation to a certain extent. Neither acid showed noticeable effects on cultured murine B16-F10 melanoma cells except weak cytotoxicity.

Open Access June 2, 2014

Nematicidal Activity of 5-Hydroxymethyl-2-furoic Acid against Plant-Parasitic Nematodes

Yasuo Kimura, Satoko Tani, Asami Hayashi, Kouhei Ohtani, Shozo Fujioka, Tsuyoshi Kawano, Atsumi Shimada

Page range: 234-238

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Abstract

A nematicide, 5-hydroxymethyl-2-furoic acid (1), was isolated from cultures of the fungus Aspergillus sp. and its structure was identified by spectroscopic analysis. Compound 1 showed effective nematicidal activities against the pine wood nematode Bursaphelenchus xylophilus and the free-living nematode Caenorhabditis elegans without inhibitory activity against plant growth, but 1 did not show any effective nematicidal activity against Pratylenchus penetrans.

Open Access June 2, 2014

Effect of Norflurazon on Resorcinolic Lipid Metabolism in Rye Seedlings

Elzbieta G. Magnucka, Yoshikatsu Suzuki, Stanislaw J. Pietr, Arkadiusz Kozubek, Robert Zarnowski

Page range: 239-245

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Abstract

Norflurazon is a selective pyridazinone herbicide excessively employed in the control of many annual grasses and broad-leaved weeds. This chemical causes plant bleaching due to the inhibition of the carotenoid pigment biogenesis as well as induces irreparable changes to chloroplasts, which are considered the organelles where the biosynthesis of resorcinolic lipids takes place. Resorcinolic lipids, a group of phenolic compounds, constitute not only an essential part of the plant antifungal defense system, but also are an important component of the human cereal diet. The aim of this study was to investigate the effect of norflurazon on the biosynthesis of resorcinolic lipids in 5-day-old rye plants (Secale cereale L.) that were grown at three different temperatures under light or dark conditions. At all tested temperatures, norflurazon decreased the fresh biomass of light-grown rye seedlings and increased the weight of plants grown in darkness. Compared with respective controls, this herbicide caused an increase in total content of alkylresorcinols in both green and etiolated plants with the exception of dark-grown norflurazon-treated rye at 29 °C. The general level of saturated homologues was markedly decreased by norflurazon in all etiolated plants and in light-grown seedlings at 15 °C. Independent of thermal and light conditions, in all norflurazon-treated samples two alkylresorcinol derivatives predominated: 1,3-dihydroxy-5-n-heptadecylbenzene and 1,3-dihydroxy-5-n-nonadecylbenzene. Thus, our results suggest that norflurazon affected the metabolism of alkylresorcinols in rye seedlings and its action was dependent on external stimuli.

Open Access June 2, 2014

UV-B Effect on Constituents of Azolla caroliniana

Mohamed M. Ibrahim, Eazaz M. Mostafa

Page range: 246-252

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Abstract

Changes in growth and ultrastructure of Azolla caroliniana in response to elevated UV-B radiation were investigated. Exposure of plants to UV-B radiation for 1, 8, 16, 24 and 48 h exhibited a significant decrease in biomass and relative growth rate. This decrease resulted in an increase in doubling time over the control. Also, Chl a and b contents were significantly decreased especially after 16 h. The reduction was accompanied by a decrease in 5-aminolaevulinic acid content (precursor of chlorophyll). On the other hand, contents of carotenoid and UV-absorbing phenolic compounds (flavonoids and anthocyanins) were increased.

Open Access June 2, 2014

Effect of Membrane Fluidity on Photosynthetic Oxygen Production Reactions

Antoaneta V. Popova, Maya Velitchkova, Yuli Zanev

Page range: 253-260

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Abstract

The effect of changes of membrane fluidity on the oxygen evolving capability of isolated thylakoids was investigated. Alteration of the lipid phase fluidity was achieved by incorporation of the plant sterol stigmasterol. Incorporation of stigmasterol in the lipid bilayer of thylakoid membranes results in rigidization of the hydrophobic phase of thylakoid membranes and decreases the degree of packing of the lipid head groups. These changes of lipid order are accompanied by a reduction of oxygen evolution, measured with 1,4-benzoquinone as an electron acceptor, and by a more pronounced inhibition of PSI-mediated electron transport. By analysis of the parameters of oxygen flash yields and oxygen burst under continuous illumination it was shown that after treatment with stigmasterol: 1.) the number of active oxygen-evolving centres decreased; 2.) the remaining active oxygen-evolving centres were not affected in respect to the oscillation pattern; 3.) the contribution of the slow oxygenevolving centres in oxygen burst yield was increased. The effect of stigmasterol was compared with the well-studied effect of cholesterol. Results were discussed in terms of determining the role of lipid order for the organization and functioning of the photosynthetic machinery.

Open Access June 2, 2014

Biosorption of Binary Mixtures of Copper and Cobalt by Penicillium brevicompactum

Kolishka Tsekova, Maria Ianis, Vera Dencheva, Sonya Ganeva

Page range: 261-264

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Abstract

This work reports on a study of the biosorption of copper and cobalt, both singly and in combination (in equimolar concentrations), by the resting cells of Penicillium brevicompactum. Equilibrium batch sorption studies were carried out at 30 °C and pH 5.0 for a contact time of 1 hour to guarantee that equilibrium was reached. The equilibrium data were analyzed using the Langmuir and Freundlich isotherms. The adsorption of binary mixtures of heavy metal solutions on the fungal biomass was found to be of competitive type where the adsorption capacity for any single metal decreased in the presence of the other. The cobalt ions showed a higher affinity for Penicillium brevicompactum than the copper ions.

Open Access June 2, 2014

Multiple Effects of Cadmium on the Photosynthetic Apparatus of Avicennia germinans L. as Probed by OJIP Chlorophyll Fluorescence Measurements

Daniel Gonzalez-Mendoza, Francisco Espadas y Gil, Jorge M. Santamaría, Omar Zapata-Perez

Page range: 265-272

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Abstract

The toxic effects of cadmium on the photosynthetic apparatus of Avicennia germinans were evaluated by means of the chlorophyll fluorescence transient O-J-I-P. The chlorophyll fluorescence transients were recorded in vivo with high time resolution and analyzed according to the OJIP-test that can quantify the performance of photosystem II. Cadmium-treated plants showed a decrease in yield for primary photochemistry, TR 0 /ABS. The performance index of photosystem II (PSII), PI ABS , decreased due to cadmium treatment. This performance index is the combination of the indexes of three independent parameters: (1) total number of active reaction centers per absorption (RC/ABS), (2) yield of primary photochemistry (TR 0 /ABS), and (3) efficiency with which a trapped exciton can move an electron into the electron transport chain (ET 0 /TR 0 ). Additionally, the F 0 /F v registered the highest sensitivity to the metal, thus indicating that the water-splitting apparatus of the oxidizing side of PSII is the primary site of action of cadmium. In summary, cadmium affects several targets of photosystem II. More specifically the main targets of cadmium, according to the OJIPtest, can be listed as a decrease in the number of active reaction centers and damage to the activity of the water-splitting complex.

Open Access June 2, 2014

L-Amino Acid Oxidases with Specificity for Basic L-Amino Acids in Cyanobacteria

Achim E. Gau, Achim Heindl, Anke Nodop, Uwe Kahmann, Elfriede K. Pistorius

Page range: 273-284

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Abstract

The two closely related fresh water cyanobacteria Synechococcus elongatus PCC 6301 and Synechococcus elongatus PCC 7942 have previously been shown to constitutively express a FAD-containing l-amino acid oxidase with high specificity for basic L-amino acids (L-arginine being the best substrate). In this paper we show that such an enzyme is also present in the fresh water cyanobacterium Synechococcus cedrorum PCC 6908. In addition, an improved evaluation of the nucleotide/amino acid sequence of the l-amino acid oxidase of Synechococcus elongatus PCC 6301 (encoded by the aoxA gene) with respect to the FAD-binding site and a translocation pathway signal sequence will be given. Moreover, the genome sequences of 24 cyanobacteria will be evaluated for the occurrence of an aoxA-similar gene. In the evaluated cyanobacteria 15 genes encoding an l-amino acid oxidase-similar protein will be found.

Open Access June 2, 2014

Isolation and Characterization of a Novel n-Alkane-Degrading Strain, Acinetobacter haemolyticus AR-46

Zoltán Bihari, Aladár Pettkó-Szandtner, Gyula Csanádi, Margit Balázs, Péter Bartos, Péter Kesserű, István Kiss, Imre Mécs

Page range: 285-295

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Abstract

Strain AR-46, isolated and identified as Acinetobacter haemolyticus, evolutionally distant from the known hydrocarbon-degrading Acinetobacter spp., proved to have excellent longchain n-alkane-degrading ability. This is the first detailed report on an n-alkane-utilizing strain belonging to this species. The preferred substrate is n-hexadecane, with an optimal temperature of 37 °C under aerobic conditions. Five complete and two partial open reading frames were sequenced and correlated with the early steps of monoterminal oxidation-initiated n-alkane mineralization. The encoded protein sequences and the arrangement of these genes displayed high similarity to those found in Acinetobacter sp. M-1, but AR-46 seemed to have only one alkane hydroxylase gene, with a completely different induction profile. Unique behaviour was also observed in n-alkane bioavailability. Substrate uptake occurred through the hydrophobic surface of n-alkane droplet-adhered cells possessing long, thick fimbriae, which were presumed to play a major role in n-alkane solubilization. A majority of the cells was in detached form, with thick, but short fimbriae. These free cells were permanently hydrophilic, unlike the cells of other Acinetobacter strains.

Open Access June 2, 2014

A New 1-Deoxy-D-xylulose 5-Phosphate Reductoisomerase Gene Encoding the Committed-Step Enzyme in the MEP Pathway from Rauvolfia verticillata

Zhihua Liao, Rong Chen, Min Chen, Chunxian Yang, Qiang Wang, Yifu Gong

Page range: 296-304

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Abstract

1-Deoxy-d-xylulose 5-phosphate (DXP) reductoisomerase (DXR; EC 1.1.1.267) catalyzes a committed step of the methylerythritol phosphate (MEP) pathway for the biosynthesis of pharmaceutical terpenoid indole alkaloid (TIA) precursors. The full-length cDNA sequence was cloned and characterized from a TIA-producing species, Rauvolfia verticillata, using rapid amplification of cDNA ends (RACE) technique. The new cDNA was named as RvDXR and submitted to GenBank® to be assigned with an accession number (DQ779286). The fulllength cDNA of RvDXR was 1804 bp containing a 1425 bp open reading frame (ORF) encoding a polypeptide of 474 amino acids with a calculated molecular mass of 51.3 kDa and an isoelectric point of 5.88. Comparative and bioinformatic analyses revealed that RvDXR showed extensive homology with DXRs from other plant species and contained a conserved transit peptide for plastids, an extended Pro-rich region and a highly conserved NADPHbinding motif in its N-terminal region owned by all plant DXRs. The phylogenetic analysis revealed that DXRs had two groups including a plant and bacterial group; RvDXR belonged to angiosperm DXRs that were obtained from Synechocystis through gene transfer according to the phylogenetic analysis. The structural modeling of RvDXR showed that RvDXR had the typical V-shaped structure of DXR proteins. The tissue expression pattern analysis indicated that RvDXR expressed in all tissues including roots, stems, leaves, fruits and followers but at different levels. The lowest transcription level was observed in followers and the highest transcription was found in fruits of R. verticillata; the transcription level of RvDXR was a little higher in roots and stems than in leaves. The cloning and characterization of RvDXR will be helpful to understand more about the role of DXR involved in R. verticillata TIA biosynthesis at the molecular level and provides a candidate gene for metabolic engineering of the TIAs pathway in R. verticillata.

Open Access June 2, 2014

In vitro Inhibition of Cholinesterases by Carbamates - A Kinetic Study

Alena Komersová, Markéta Masopustová, Karel Komers, Šárka Štěpánková, Alexandr Čegan

Page range: 305-307

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Abstract

Kinetics and mechanism of in vitro hydrolyses of acetylcholine and acetylthiocholine by carbamates were studied in a batch reactor at 25 °C, pH 8, and ionic strength of 0.11 m. Every hydrolysis was monitored by 3-4 independent methods. All studied hydrolyses can be described by the model of competitive inhibition with an irreversible step (k 3 ). A table of obtained average values of rate constants and discussion of the resultes are given.

Open Access June 2, 2014

Inhibition of Cholinesterase by Dialkylcarbamates

Šárka Štĕpánková, Karel Komers, Alena Komersová, Markéta Masopustová, Alexander Čegan

Page range: 308-310

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Abstract

The pI 50 index and separation coefficients of chosen 3-N,N-diethylaminophenyl-N′,N′-dialkylcarbamates were determined. Index pI 50 (pI 50 = negative logarithm of molar concentration of inhibitor inhibiting the enzyme activity by 50%) describes the effectiveness of the inhibitor. The rate of ability of the inhibitor to pass the blood-brain barrier is usually described by the separation coefficient in a system n-octanol/water (K ow ). Obtained results were compared with pI 50 and K ow of Exelon®, the commercially used drug against the Alzheimer’s disease.

About this journal

Objective

A Journal of Biosciences: Zeitschrift für Naturforschung C (ZNC) is an international scientific journal and a community resource for the emerging field of natural and natural-like products.

The journal publishes original research on the isolation (including structure elucidation), bio-chemical synthesis and bioactivities of natural products, their biochemistry, pharmacology, biotechnology, and their biological activity and innovative developed computational methods for predicting the structure and/or function of natural products.

A Journal of Biosciences: Zeitschrift für Naturforschung C (ZNC) welcomes research papers in fields on the chemistry-biology boundary which address scientific ideas and approaches to generate and understand natural compounds on a molecular level and/or use them to stimulate and manipulate biological processes.

Topics

Bio-chemical synthesis and bioactivities of natural products
Isolation (including structure elucidation)
Biochemistry
Biotechnology
Pharmacology
Chemistry
Biology

Article formats

Original research articles, research notes, letters and review articles

Please have a look at the call for papers for two upcoming Special Issues:

Special Issue on CAZymes

Special Issue on Chitin Structures and Pathways as Targets for Biopesticides and Drugs