The antibacterial activity of Libanstin from Ilex paraguariensis (Yerba Mate)

Infectious diseases are reported to be one of the major causes of death in the world. The World Health Organization (WHO) warns of an increase in the deaths number because of antibacterial resistance. Lately, a trend towards searching for new active antibacterial compounds in plants has been observed. Ilex paraguariensis, known as Yerba Mate, is a plant known to be rich in numerous bioactive compounds that have an important role in human health. In this study, Yerba Mate was extracted with acetone: water (1:1) and further fractionated with hexane, chloroform and ethyl acetate. The obtained fractions were tested for antibacterial activity against Staphylococcus aureus and Salmonella species. The minimum inhibitory concentration (MIC) values on S. aureus ranged from 1.56 to 3.12 mg/mL for both the chloroform and ethyl acetate fractions. Whereas for the water fraction, the MIC values ranged from 0.78 to 3.12 mg/mL on S. aureus and ranged from 1.56 mg/mL to 3.12 mg/mL on Salmonella species. The aqueous fraction was further treated with different enzymes to mimic in vivo digestion and the fractions obtained were then tested for antibacterial activity. Furthermore, the Yerba Mate aqueous fraction was run on High Performance Liquid Chromatography (HPLC) and collected fractions were tested for antibacterial activity, to identify the active metabolite. Fraction 3 was tested on different strains of S. aureus and the MIC values ranged from 0.19 to 1.56 μg/mL. A novel pyrazinone, Libanstin, from Ilex paraguariensis was identified using NMR spectroscopy.

Research Progress of the Biosynthesis of Natural Bio-Antibacterial Agent Pulcherriminic Acid in Bacillus

Pulcherriminic acid is a cyclic dipeptide found mainly in Bacillus and yeast. Due to the ability of pulcherriminic acid to chelate Fe3+ to produce reddish brown pulcherrimin, microorganisms capable of synthesizing pulcherriminic acid compete with other microorganisms for environmental iron ions to achieve bacteriostatic effects. Therefore, studying the biosynthetic pathway and their enzymatic catalysis, gene regulation in the process of synthesis of pulcherriminic acid in Bacillus can facilitate the industrial production, and promote the wide application in food, agriculture and medicine industries. After initially discussing, this review summarizes current research on the synthesis of pulcherriminic acid by Bacillus, which includes the crystallization of key enzymes, molecular catalytic mechanisms, regulation of synthetic pathways, and methods to improve efficiency in synthesizing pulcherriminic acid and its precursors. Finally, possible applications of pulcherriminic acid in the fermented food, such as Chinese Baijiu, applying combinatorial biosynthesis will be summarized.

Optimal extraction bioactive components of tetramethylpyrazine in Chinese herbal medicine jointly using back propagation neural network and genetic algorithm in R language

A combinational approach of back propagation neural network (BPNN) and genetic algorithm (GA) was proposed in the present study to optimize the extraction technology of tetramethylpyrazine (TMP) in Ligusticum wallichii Franchat. Based on the single factor test, the orthogonal experiment design method of four factors and three levels was adopted, and the concentration of TMP was measured by high performance liquid chromatography (HPLC). Subsequently, BPNN model was trained for a predictive computational model of the performance indices via experimental data, and GA was exploited to find the optimization con ditions for extraction technology of TMP. Meanwhile, both the model and algorithm were implemented in R language. Ethanol concentration of 80%, extraction time of 1.5h, extraction temperature of 55℃ and liquid-solid ratio of 8:1 were derived as optimal conditions with a maximum content of TMP of 2.04 mg/g, which was confirmed with the relative error 2.63% through the validation of the experiments. This mathematical model could be used to analyze and predict the extraction technology of TMP in Ligusticum wallichii Franchat and provide a new reference for screening optimization of Chinese medicine effective parts and components.

Enhypyrazinones A and B, Pyrazinone Natural Products from a Marine-Derived Myxobacterium Enhygromyxa sp

To date, studies describing myxobacterial secondary metabolites have been relatively scarce in comparison to those addressing actinobacterial secondary metabolites. This realization suggests the immense potential of myxobacteria as an intriguing source of secondary metabolites with unusual structural features and a wide array of biological activities. Marine-derived myxobacteria are especially attractive due to their unique biosynthetic gene clusters, although they are more difficult to handle than terrestrial myxobacteria. Here, we report the discovery of two new pyrazinone-type molecules, enhypyrazinones A and B, from a marine-derived myxobacterium Enhygromyxa sp. Their structures were elucidated by HRESIMS and comprehensive NMR data analyses. Compounds 1 and 2, which contain a rare trisubstituted-pyrazinone core, represent a unique class of molecules from Enhygromyxa sp.

N-containing compounds from Periplaneta americana and their activities against wound healing

Three new compounds, periplanamides A (1) and B (2), periplanpyrazine A (3), a new naturally occurring compound salicyluric acid methyl ester (6), and seventeen known compounds were isolated from the medicinal insect Periplaneta americana. The structures of the new compounds were elucidated on the basis of spectroscopic methods. The absolute configurations of 2 were assigned by computational methods. Biological activities of these isolates except 1, 9, 11, and 13 toward nitric oxide (NO) production, cell proliferation in HDFs, cell migration and angiogenesis in HUVECs were evaluated.

Novel Antimicrobial Indolepyrazines A and B from the Marine-Associated Acinetobacter sp. ZZ1275

Two new alkaloids indolepyrazines A (1) and B (2) were isolated from the marine-derived Acinetobacter sp. ZZ1275. Their structures were elucidated through extensive nuclear magnetic resonance (NMR) spectroscopic analyses, high resolution electrospray ionization mass spectroscopy (HRESIMS) data, and electronic circular dichroism (ECD) calculation. Indolepyrazine A represents the first example of alkaloids with an indole-pyrazine-oxindole skeleton. Both 1 and 2 showed antimicrobial activities against methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans with minimum inhibitory concentration (MIC) values of 12 μg/mL, 8–10 μg/mL, and 12–14 μg/mL, respectively.

Chemical and Sensory Evaluation of Magnetic Polymers as a Remedial Treatment for Elevated Concentrations of 3-Isobutyl-2-methoxypyrazine in Cabernet Sauvignon Grape Must and Wine

3-Isobutyl-2-methoxypyrazine (IBMP) is a potent odorant present in grapes and wines that is reminiscent of green capsicum. Suprathreshold concentrations can lead to obvious vegetative characters and suppress desirable fruity aroma nuances in wines, but options to manage IBMP concentrations are limited. This work investigated pre- and postfermentation addition of a putative imprinted magnetic polymer (PIMP) as a remedial treatment for elevated concentrations of IBMP in Cabernet Sauvignon grape must in comparison to nonimprinted magnetic polymer (NIMP) and to a commercially available polylactic acid (PLA) based film added postfermentation. Chemical and sensory analyses of wines showed that PIMP treatments were more effective than PLA film for decreasing "fresh green" aroma nuances without negatively impacting overall aroma profiles and that postfermentation addition of a magnetic polymer removed up to 74% of the initial IBMP concentration compared to 18% for PLA. Prefermentation addition of magnetic polymers removed 20-30% less IBMP compared to that of postfermentation addition but also had less of an effect on other wine volatiles and color parameters.

Bioactive Bafilomycins and a New N-Arylpyrazinone Derivative from Marine-derived Streptomyces sp. HZP-2216E

A MeOH extract prepared from culture of an actinomycete Streptomyces sp. HZP-2216E isolated from marine green algae Ulva pertusa was found to significantly inhibit proliferation of human glioma cells. Two different media were applied to culture this marine actinomycete, which produced two new compounds of 23-O-butyrylbafilomycin D and streptoarylpyrazinone A, together with known bafilomycin D, 9-hydroxybafilomycin D, and bafilomycin A₁. Structures of new compounds were determined by extensive NMR spectroscopic analyses and HRESIMS data. Bioactive assay indicated that all isolated bafilomycins significantly inhibited the proliferation of different glioma cell lines and the growth of methicillin-resistant Staphylococcus aureus with 23-O-butyrylbafilomycin D as the most active compound. Streptoarylpyrazinone A is a new N-arylpyrazinone derivative existing as a zwitterion, and this type of compounds was rarely found from natural resources.

Five Unprecedented Secondary Metabolites from the Spider Parasitic Fungus Akanthomyces novoguineensis

Five new compounds including the glycosylated β-naphthol (1, akanthol), a glycosylated pyrazine (2, akanthozine), and three amide derivatives including a hydroxamic acid derivative (3–5) were isolated from the spider-associated fungus Akanthomyces novoguineensis (Cordycipitaceae, Ascomycota). Their structures were elucidated by using high resolution mass spectrometry (HRMS) and NMR spectroscopy. In this study, the antimicrobial, cytotoxic, anti-biofilm, and nematicidal activities of the new compounds were evaluated. The distribution pattern of secondary metabolites in the species was also revealed in which more isolates of A. novoguineensis were encountered and their secondary metabolite profiles were examined using analytical HPLC with diode array and mass spectrometric detection (HPLC-DAD/MS). Remarkably, all isolated compounds are specifically produced by A. novoguineensis.

Isolation and identification of new chemical constituents from Chinese chive (Allium tuberosum) and toxicological evaluation of raw and cooked Chinese chive

Chinese chive (jiu cai) is a popular vegetable in China and has a unique flavour and aroma. The molecular basis of the characteristic fragrance and nutritional properties of Chinese chive has not been previously identified. Sequential extractions in a series of solvents and high-performance liquid chromatography were used to isolate 40 compounds from Chinese chive. The compounds were identified based on high-resolution electrospray ionization mass spectra, 1D and 2D nuclear magnetic resonance techniques, and circular dichroism spectra. Eight novel compounds were identified-four new pyrazines, which have distinctive flavour; one new lignan; and three new flavonoids-together with 32 known compounds. Several of these compounds have potential applications as health-promoting dietary supplements, food additives, or seasonings. Additionally, the volatile organic compounds in fresh and steamed Chinese chive were compared, and the toxicological activity of extracts from fresh and steamed Chinese chive was tested in normal rat liver (IAR20) and kidney (NRK) cells. The results showed that Chinese chive is toxic to liver and kidney cells when fresh, but is safe after heating. This could explain why it is traditional to eat cooked Chinese chive. A possible metabolic rule regarding pyrazines is postulated based on this data, and a human metabolic pathway is suggested for two of the novel compounds which have the highest amount of Chinese chive extracts.

Investigating a persistent odor at an aircraft seat manufacturer

An aircraft seat manufacturing company requested a NIOSH health hazard evaluation to help identify a strong odor that had persisted throughout the facility for over a year. Employees reported experiencing health effects thought to be related to the odor. We collected and analyzed area air samples for volatile organic compounds, endotoxin, bacterial and fungal metagenome, and metalworking fluid aerosol. Bulk metalworking fluid samples were analyzed for endotoxin, bacterial and fungal metagenome, and viable bacteria and fungus. We also evaluated the building ventilation systems and water diversion systems. Employees underwent confidential medical interviews about work practices, medical history, and health concerns. Based on our analyses, the odor was likely 2-methoxy-3,5-dimethylpyrazine. This pyrazine was found in air samples across the facility and originated from bacteria in the metalworking fluid. We did not identify bacteria known to produce the compound but bacteria from the same Proteobacteria order were found as well as bacteria from orders known to produce other pyrazines. Chemical and biological contaminants and odors could have contributed to health symptoms reported by employees, but it is likely that the symptoms were caused by several factors. We provided several recommendations to eliminate the odor including washing and disinfecting the metalworking machines and metalworking fluid recycling equipment, discarding all used metalworking fluid, instituting a metalworking fluid maintenance program at the site, and physically isolating the metalworking department from other departments.

Marine-Derived Secondary Metabolite, Griseusrazin A, Suppresses Inflammation through Heme Oxygenase-1 Induction in Activated RAW264.7 Macrophages

A new secondary metabolite, named griseusrazin A (1), was isolated from the marine-derived bacterium Streptomyces griseus subsp. griseus. The structure of the compound was determined by analysis of spectroscopic data including MS, COSY, HSQC, HMBC, and (15)N-HMBC data. Griseusrazin A (1) inhibited the production of inflammatory mediators, such as prostaglandin E2 and nitric oxide, which was mediated through the suppression of the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The production of pro-inflammatory cytokines, such as interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α, in the LPS-stimulated cells was also effectively blocked by griseusrazin A (1). Furthermore, this anti-inflammatory activity of 1 was linked to its inhibitory effects against the nuclear translocation of NF-κB p50 and p65, as wells as NF-κB binding activity. In the further study to elucidate the anti-inflammatory mechanism, 1 was shown to induce heme oxygenase-1 (HO-1) expression through the enhancement of nuclear translocation of nuclear factor E2-related factor 2. Furthermore, the anti-inflammatory activity of 1 in the LPS-stimulated cells was partially reversed by an HO inhibitor, tin protoporphyrin. These results indicate that the anti-inflammatory effect of 1 is associated with Nrf2-mediated HO-1 expression.

Terezine derivatives from the fungus Phoma herbarum PSU-H256

Investigation of the fungus Phoma herbarum PSU-H256 isolated from a leaf of Hevea brasiliensis resulted in the isolation of eight terezine derivatives (E-L) together with four known compounds. Their structures were established by analysis of spectroscopic evidence. For terezines E and H, their structures were confirmed by single-crystal X-ray diffraction crystallography. In addition, the absolute configuration at C-7 in terezine E was established by Mosher's method. Terezines K and L were tested for antibacterial, antimalarial, antimycobacterial and cytotoxic activities, but were inactive.

[Study on recovery and its influencing factors of ferulic acid and tetramethylpyrazine in cerebral microdialysis probe]

To establish a method for detecting microdialysis recovery of tetramethylpyrazine (TMP) and ferulic acid (FA) and investigating the influencing factors, providing the basis for further in vivo microdialysis experiments. The concentration of FA and TMP in dialysates were determined by high pressure liquid chromatography ( HPLC) and probe recovery were calculated respectively. The influence of the flow rates, medium concentration, temperature and in vivo probe stability on the recovery of FA and TMP were investigated by using concentration difference method (incremental method and decrement method). The recovery obtained by incremental method were similar to by decrement method. The in vitro recovery rate of FA and TMP decreased with the increase of 1-2.5 μL min(-1), and increased obviously with the temperature of 25-42 degrees C under the same conditions. The concentration of FA and TMP had no obvious effect on the probe recovery under the same flow rate. In addition, the recovery of TMP and FA remained stable and showed similar trends under the condition of four concentration cycles, indicating that the intra day reproducibility of the concentration difference method was good. The recovery of brain microdialysis probes in vivo 8 h maintained a relatively stable, but certain differences existed between different brain microdialysis probes, demonstrating that each probe was required for recovery correction in vivo experiment. Microdialysis sampling can be used for the local brain pharmacokinetic study of FA and TMP, and retrodialysis method can be used in probe recovery of FA and TMP in vivo.

Treatment technologies and mechanisms for three odorants at trace level: IPMP, IBMP, and TCA

Odour episodes caused by algal metabolites are gaining more and more attention in recent years. Besides geosmin and 2-methylisoborneol (MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), and 2,4,6-trichloroanisole (TCA) have emerged to be important off-flavour sources. Their low odour threshold concentrations (several ng ·L(-1)), which are even lower than those of MIB and geosmin, pose challenges for treatment strategies. Hence, a practical and efficient mitigation technology is needed. The possible practical technologies, including powdered activated carbon (PAC) adsorption and oxidation by chlorine and potassium permanganate, were investigated. The results indicated that chlorine and potassium permanganate oxidation of the three odorants were unfeasible while PAC adsorption was effective. As for adsorption, TCA, followed by IBMP and IPMP, was most easily removed by PAC. The Freundlich model could well describe the adsorption isotherm data. The adsorption capacities for IPMP, IBMP, and TCA were described as follows: [Formula: see text], [Formula: see text], and [Formula: see text]. For five earthy/musty odorants including geosmin and MIB, octanol/water partition coefficient, molecular weight, and polarizability all promoted adsorption while aqueous solubility showed a negative influence. The hydrophobic interaction was believed to be the dominant force in the adsorption mechanism while the π-electron interaction enhanced adsorption when a benzene ring was present. This result could be used to predict the adsorption performance of emerging odorants.

Nannozinones and sorazinones, unprecedented pyrazinones from myxobacteria

Nannozinones A (1) and B (2) were discovered as metabolites of the recently isolated Nannocystis pusilla strain MNa10913 belonging to the poorly studied myxobacterial family Nannocystaceae. In contrast, the structurally related sorazinones A (5) and B (6) were isolated from Sorangium cellulosum strain Soce895, which was known as the producer of the antibiotic thuggacin A. The extract also contained methyl indole-3-carboxylate (4). HRESIMS and (1)H, (13)C, and (15)N NMR spectroscopy revealed the structures of nannozinones A (1) and B (2) as unusual dihydropyrrolo- and pyrrolopyrazinone derivatives, while sorazinone A (5) was characterized as an aromatic diketopiperazine and sorazinone B (6) as a dibenzyl 2(1H)-pyrazinone derivative. While the dihydropyrrolo derivative nannozinone A (1) showed weak antibacterial and antifungal activity, nannozinone B (2) inhibited the growth of cell cultures with IC50 values between 2.44 and 16.9 μM. The nannochelin A iron complex (3), which was isolated besides 1 and 2, was even more active, with IC50 values between 0.05 and 1.95 μM. On the other hand, the indole 4 and sorazinones 5 and 6 did not show any significant cytotoxicity and only weak activity against the Gram-positive Nocardia sp.

Unusual 2(1H)-pyrazinones isolated from a culture of a Brazilian marine-derived Streptomyces sp

Four new secondary metabolites, giovaninones A-D (1-4), were isolated from an ethyl acetate extract of a culture of a marine-derived Streptomyces strain designated SS99BA-2. Chemical analysis was completely conducted in a coupled automated LC-SPE system with the use of a cryogenic NMR probehead and HRMS. The application of this system to identify, purify and elucidate all the structures is described.

Aroma-active components of yeast extract pastes with a basic and characteristic meaty flavour

BACKGROUND

Aroma-active compounds, together with sugars, amino acids, fat and nucleotides, are the main chemical species determining the characteristic aroma and taste of food. For selecting yeast extract pastes products with a less undesirable aroma, the aroma-active compounds that affect the overall consumer acceptance of yeast extract pastes products were analysed in this work.

RESULTS

The aroma-active compounds of yeast extract pastes were extracted by using dynamic headspace extraction or simultaneous distillation extraction, and were detected by gas chromatography-olfactrometry-mass spectrometry in conjunction with dynamic headspace dilution analysis or aroma extract dilution analysis. Sensory results revealed that a meaty, roasted aroma was the dominant of overall aroma. The important aroma-active compounds referred in this work were mainly aldehydes, acids, ketones, furan derivatives, pyrazines, and sulfur-containing compounds. Of these, six volatile compounds such as 3-methylbutanal, 2,3-butanedione, 2,3,5-trimethyl-pyrazin, acetic acid ethenyl ester, 2-acetyl-1-pyrroline and (E,E)-2,4-decadienal had never been reported before as key aroma-active compounds of yeast extract pastes.

CONCLUSIONS

The key aroma-active compounds were identified in basic and characteristic meaty flavour yeast extract pastes, and their characterisation was determined.

Favipiravir (T-705), a novel viral RNA polymerase inhibitor

Favipiravir (T-705; 6-fluoro-3-hydroxy-2-pyrazinecarboxamide) is an antiviral drug that selectively inhibits the RNA-dependent RNA polymerase of influenza virus. It is phosphoribosylated by cellular enzymes to its active form, favipiravir-ribofuranosyl-5'-triphosphate (RTP). Its antiviral effect is attenuated by the addition of purine nucleic acids, indicating the viral RNA polymerase mistakenly recognizes favipiravir-RTP as a purine nucleotide. Favipiravir is active against a broad range of influenza viruses, including A(H1N1)pdm09, A(H5N1) and the recently emerged A(H7N9) avian virus. It also inhibits influenza strains resistant to current antiviral drugs, and shows a synergistic effect in combination with oseltamivir, thereby expanding influenza treatment options. A Phase III clinical evaluation of favipiravir for influenza therapy has been completed in Japan and two Phase II studies have been completed in the United States. In addition to its anti-influenza activity, favipiravir blocks the replication of many other RNA viruses, including arenaviruses (Junin, Machupo and Pichinde); phleboviruses (Rift Valley fever, sandfly fever and Punta Toro); hantaviruses (Maporal, Dobrava, and Prospect Hill); flaviviruses (yellow fever and West Nile); enteroviruses (polio- and rhinoviruses); an alphavirus, Western equine encephalitis virus; a paramyxovirus, respiratory syncytial virus; and noroviruses. With its unique mechanism of action and broad range of antiviral activity, favipiravir is a promising drug candidate for influenza and many other RNA viral diseases for which there are no approved therapies.

[Effects of ligustrazine on extracellular dopamine levels in rat brain dialysate]

Using brain microdialysis and LC-ECD, the content of dopamine in rat brain was detected to investigate the effects of ligustrazine. A liquid chromatography-electrochemical detector method has been established and validated for the determination of dopamine in rat brain dialysate. The results indicate that ligustrazine administration by subcutaneous injection significantly increased dopamine release in rat medial prefrontal cortex, nucleus accumbens and hippocampus in a dose-related manner. The drug's effects on dopa release in rat brain could be directly detected by microdialysis combined with HPLC-ECD and this method has the preponderance over traditional neurology methods.

Secondary metabolites from a culture of the fungus Neosartorya pseudofischeri and their in vitro cytostatic activity in human cancer cells

Four known (1, 2, 3, and 6) and three new compounds including a 1,4-diacetyl-2,5-dibenzylpiperazine derivative (4), a quinazolinone-containing indole derivative (5), and a new ester of 2,4-dihydroxy-6-methylbenzoic acid (7) were isolated from the fungus Neosartorya pseudofischeri S. W. Peterson. Compound 2 displayed in vitro growth inhibitory activity that ranged between the activities of etoposide and carboplatin, chosen as reference compounds, in six distinct cancer cell lines. Compound 1 displayed less activity than 2. Computer-assisted phase-contrast microscopy-related analysis revealed that 2 displayed cytostatic, not cytotoxic, effects in human U373 glioblastoma and A549 non-small cell lung cancer apoptosis-resistant cells with marked inhibition of mitotic rates. Cancer cells in the remaining phases of the cell cycle were unchanged. Flow cytometry analysis further confirmed that 2 does not induce apoptotic features in U373 or A549 cancer cells. Thus, 2 represents a novel chemical scaffold from which derivatives for anticancer cytostatic compounds can be derived.

JBIR-56 and JBIR-57, 2(1H)-pyrazinones from a marine sponge-derived Streptomyces sp. SpD081030SC-03

Strain SpD081030SC-03, representing a novel species of Streptomyces, was isolated from a marine sponge. Two 3,5,6-trisubstituted 2(1H)-pyrazinones, JBIR-56 (1) and JBIR-57 (2), were isolated from a culture of SpD081030SC-03. The planar structures of 1 and 2 were assigned on the basis of extensive NMR and MS analyses. In addition, analyses of the methylated derivative of 1 confirmed a 3,5,6-trisubstituted 2(1H)-pyrazinone moiety. The absolute configurations of the amino acid residues were determined by application of Marfey's method. Because 1 did not appear to comprise the normal connection of amino acid units, we confirmed its structure by the total synthesis of 1. Biosynthetically, 1 consists of a unique skeleton connected to the peptide chain at C-5 of the pyrazinone ring.

Impacts of bicyclo-monoterpene enhancers on transdermal delivery of ligustrazine

The purpose of this study is to investigate the impacts of bicyclo-monoterpene promoters (i.e., borneol and camphor) on the in vitro permeation of ligustrazine (LGT) through the hairless porcine dorsal skin. Fourier transform-infrared (FT-IR), scanning electron microscope (SEM) and transdermal delivery kinetics in vitro were performed to investigate the effect of the promoters on the biophysical changes to the stratum corneum (SC), the surface changes to porcine skin and the in vitro percutaneous fluxes of ligustrazine through procine skin. FT-IR results revealed that the peak shift and the decrease in the peak area with borneol were higher than those with camphor. SEM studies demonstrated that the morphological change to SC was related to the chosen enhancer. It was observed that the SC lipid extraction with borneol and camphor led to disruption of the SC and the scutella desquamation. Apparent density (AD) was utilized to describe the desquamation extent of the scutella. Percutaneous fluxes of ligustrazine through porcine skin were evaluated in vitro by the Franz-type diffusion cells. Use of borneol led to greater penetration of ligustrazine across porcine skin. It was shown that the permeation enhancement mechanism of bicyclo-monoterpenes to ligustrazine included extracting and disordering lipids which involved the shift changes in C-H stretching and H-bonding action between enhancers and cermaide. The penetration capability of the hydroxy groups in bicyclo-monoterpenes was better than that of the ketone groups.

Identification of alkyl-methoxypyrazines as the malodorous compounds in water supplies from Northwest Spain

A study of organic compounds which caused several odor problems in water supplies from NW Spain was carried out. Sour dish-cloths, potato bin and musty were the main descriptors associated with these events. Closed loop stripping analysis combined with sensory-GC and GC/MS detection was used. The compound producing the initial odor event was 3,5-dimethyl-2-methoxypyrazine, identified for the first time as the compound responsible for odor incidents in finished water. Concentration levels were up to 300 ng/L in the effluent from an activated sludge wastewater treatment plant (WWTP) and 3 ng/L in finished water. 3-isobutyl-2-methoxypyrazine and other alkyl methoxypyrazines were the compounds responsible for the odor events that occurred several months later. Concentration levels in the mg/L range were measured in the activated sludge of a WWTP.

Tetramethylpyrazine inhibits production of nitric oxide and inducible nitric oxide synthase in lipopolysaccharide-induced N9 microglial cells through blockade of MAPK and PI3K/Akt signaling pathways, and suppression of intracellular reactive oxygen species

AIM OF THE STUDY

To determine the inhibitory effect of tetramethylpyrazine (TMP) on lipopolysaccharide (LPS)-induced over-production of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in N9 microglial cells.

MATERIALS AND METHODS

N9 cells were pretreated with vehicle or TMP and then exposed to LPS for the time indicated. Cell viability was determined by methylthiazoyltetrazolium (MTT) assay. Nitrite assay was performed by Griess reaction. Expression of iNOS mRNA was examined by RT-PCR. Protein levels of iNOS, p38 mitogen-activated protein kinase (MAPK), ERK1/2, JNK, phosphatidylinositol 3-kinase (PI3K) and Akt were determined by western blot analysis. Formation of reactive oxygen species (ROS) was evaluated by fluorescence image system.

RESULTS

TMP inhibited LPS-induced over-production of NO and iNOS in N9 cells. TMP also inhibited the NF-kappaB translocation from cytoplasm into nucleus of N9 cells. In addition, TMP showed blocking effect on the phosphorylation of p38 MAPK, ERK1/2, JNK and Akt, but not PI3K. Further, TMP suppressed the formation of intracellular ROS in LPS-induced N9 cells.

CONCLUSIONS

TMP inhibited production of NO and iNOS in LPS-induced N9 cells through blocking MAPK and PI3K/Akt activation and suppressing ROS production.

Alkaloids and sesquiterpenoids from Acorus tatarinowii

The rhizome of Acorus tatarinowii is a well-known traditional Chinese medicine. Our extensive investigation on this plant material afforded two new compounds, including a cadinane-type sesquiterpenoid and a pyrazine derivative, along with seven known compounds. The structures of the new compounds, tatarinowin B and tatarinine A, were elucidated as 2-oxocadinan-1(10),3-dien-5-ol (1) and 2-(3',4'-dihydroxy-1'-butylenyl)-5-(2'',3'',4''-trihydroxybutyl)-pyrazine (2), respectively, by means of spectral methods.

[Artificial neural network parameters optimization software and its application in the design of sustained release tablets]

Artificial neural network (ANN) is a multi-objective optimization method that needs mathematic and statistic knowledge which restricts its application in the pharmaceutical research area. An artificial neural network parameters optimization software (ANNPOS) programmed by the Visual Basic language was developed to overcome this shortcoming. In the design of a sustained release formulation, the suitable parameters of ANN were estimated by the ANNPOS. And then the Matlab 5.0 Neural Network Toolbox was used to determine the optimal formulation. It showed that the ANNPOS reduced the complexity and difficulty in the ANN's application.

Extraction with SPME and synthesis of 2-methyl-6-vinylpyrazine by a 'one pot' reaction using microwaves

A synthesis of 2-methyl-6-vinylpyrazine was carried out by way of a 'one pot' reaction. In order to establish the efficiency of this synthesis the extraction of the volatiles released by male papaya fruit flies was performed by SPME (solid phase micro-extraction). The compound was separated and identified using GC/MSD (gas chromatography/mass spectrometry detector).

[Effects of ligustrazine on extracellular acetylcholine levels in rat brain dialysate]

Using brain microdialysis and LC-MS/MS to detect acetylcholine in rat brain to investigate the effects of ligustrazine. A liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of acetylcholine in rat brain dialysate sampling by microdialysis. The results indicated that ligustrazine administration by subcutaneous injection significantly increased Ach release in rat medial prefrontal cortex and nucleus accumbens in a dose-related manner. The drug' s effect on Ach release in rat brain could be directly detected by microdialysis combined with HPLC-MS/MS and this method is selective and sensitive.

[Determination and fingerprint analysis of tetramethylpyrazine and ferulic acid in Ligusticum chuanxiong]

OBJECTIVE

To determine the contents of tetramethylpyrazine (TMP) and ferulic acid in Ligusticum chuanxiong from different producing areas and seasons.

METHODS

The contents of TMP and ferulic acid were determined by HPLC, and then analyzed by Chromatographic Fingerprints.

RESULTS

The contents of TMP and ferulic acid from different seasons were obviously different from each other. It was much higher in "laoxiong" than that in "naixiong". The similarity of fingerprints was high if the samples were collected from the same season, or the same areas, but not different seasons.

CONCLUSIONS

The contents of TMP and ferulic acid were different from different producing areas. The evident variety of Ligusticum chuanxiong's fingerprints from different collecting seasons, Laoxiong and Naixiong, was not relevant for clinical use as the same medicine.

Characterization of pyrazines in some Chinese liquors and their approximate concentrations

Pyrazines are very important impact aroma compounds in Chinese liquors. The identification of pyrazine derivatives was carried out by liquid-liquid extraction (LLE). The liquor sample was adjusted to the H(+) concentration of 1 N with 12 N HCl and then concentrated by rotatory evaporator under vacuum condition. The concentrated liquor was extracted by diethyl ether, and the residual aqueous phase was adjusted to pH 10. The basic compounds were detected and identified by gas chromatography (GC)-mass spectrometry (MS). A total of 27 pyrazines were identified in Chinese liquors, mainly alkyl- and acetylpyrazines. A method for determining pyrazines in Chinese liquors was developed. It involves extraction by headspace (HS) solid phase microextraction (SPME) and determination using GC-flame thermionic detector (FTD). The optimum method was that the sample alcohol concentration was diluted to 12% vol by freshly redistilled-deionized water, and the diluted samples were saturated with NaCl and equilibrated at 50 degrees C for 15 min and extracted for 30 min at the same temperature. The developed method enabled detection limits of <200 ng/L. Linearity (R(2) > 0.99) and recovery rate were satisfied in all cases. Pyrazines of 12 commercial typical Chinese liquors were quantified by HS-SPME followed by GC-FTD and had a wide range of concentration.

A novel analgesic pyrazine derivative from the leaves of Croton tiglium L

A novel analgesic pyrazine derivative, named crotonine, was isolated from the leaves of Croton tiglium L. The structure was elucidated as 2-(furan-2-yl)-5-(2,3,4-trihydroxy-butyl)-1,4-diazine by spectroscopic analysis. Crotonine inhibited remarkably the acetic acid-induced writhing in mice.

Bisindole alkaloids of the topsentin and hamacanthin classes from a marine sponge Spongosorites sp

Seven new (1 and 3-8) and seven known (2 and 9-14) bisindole alkaloids of the topsentin and hamacanthin classes were isolated from the MeOH extract of a marine sponge Spongosorites sp. by bioactivity-guided fractionation. The structure of compound 7 is a revision from our previous report. The planar structures were established on the basis of NMR and MS spectroscopic analyses. Configurations of these compounds were defined by NMR spectroscopy and optical rotation. It is noteworthy that both R and S isomers were isolated for the hamacanthins (1-4, 9, 10, 15, and 16), while a single stereoisomer was isolated for dihydrohamacanthins (5, 11-14, 17, and 18). Compounds 1-4, 6, and 8-14 showed marginal cytotoxicity against five human solid tumor cell lines, and compound 2 showed weak antibacterial activity against clinically isolated methicillin-resistant strains.

New caulerpenyne-derived metabolites of an Elysia sacoglossan from the South Indian coast

Chemical analysis of the secondary metabolite pattern of the sacoglossan mollusc Elysia cf. expansa, collected along South Indian coasts, showed the presence of the typical Caulerpa-derived sesquiterpene caulerpenyne (1) and two new minor co- occurring metabolites, the compounds dihydrocaulerpenyne (4) and expansinol (5). The chemical characterization of these molecules, structurally related to 1, is reported.

[Effects of tetramethylpyrazine on expression of vascular endothelial growth factor and hypoxia-induced factor-1alpha by rat peritoneal macrophages]

OBJECTIVE

To investigate the effects of tetramethylpyrazine on lipopolysaccharides (LPS)-induced expression of vascular endothelial growth factor (VEGF) and hypoxia-induced factor-1alpha (HIF-1alpha) in macrophages.

METHOD

Rat peritoneal macrophages were treated with LPS, and at the same time given different doses of tetramethylpyrazine. The secreation of VEGF was determined by ELISA test, and MTT assay was used to examine cells proliferation. Western blot assay was used to examine the expression of HIF-1alpha.

RESULT

100 microg x mL(-1) and 10 microg x mL(-1) tetramethylpyrazine decreased the secretion of VEGF and also inhibited the expression of HIF-1alpha by LPS-induced macrophages. But these doses of tetramethylpyrazine had no effect on the cells proliferation.

CONCLUSION

Tetramethylpyrazine could inhibit the secretion of VEGF by LPS-induced macrophages, and the mechanism must be associated with inhibiting the expression of HIF-1alpha. The inhibition effect was not due to inhibition of the proliferation of macrophages.

[The effect of tetramethylpyrazine on the pharmacokinetics of intragastrically administered cyclosporine A in rats]

AIM

To investigate the possible effect of tetramethylpyrazine (TMP), an active ingredient of a commonly used Chinese herb, on the pharmacokinetics of cyclosporine A (CsA) by intragastric administration in rats.

METHODS

Forty male Sprague-Dawley rats were equally divided into four groups by randomized block design according to weight. On the first day, after each fasting rat was intragastrically administered CsA (10 mg x kg(-1)), blood samples (0.2 - 0.25 mL) were collected from the tail vein at 0, 1, 2, 3, 4, 6, 8, 12, 24, 36 and 48 h. From day 4 to day 8, each group began to undergo different pretreatments with intragastric administration of water, verapamil (Ver), low and high dose TMP, separately. On day 9, each group intragastrically co-administered CsA (10 mg x kg(-1)) and different pretreatment compounds mentioned above, then blood samples were collected according to the schedule of the first day. The whole blood concentration of CsA was determined by HPLC. Main pharmacokinetic parameters were calculated and compared by statistic analysis.

RESULTS

In the group of water pretreated and co-administrated with CsA, no significantly different pharmacokinetic parameters of CsA were found. After Ver pretreatment and co-administration with CsA, AUC(0-48 h) and C(max) were increased significantly (P < 0.01 and P < 0.05); T(1/2) beta and CL were markedly prolonged and decreased (P < 0.05); T(max) and V were not apparently influenced. After low dose TMP pretreatment and co-administration with CsA, there was no significant difference in the pharmacokinetic parameters of CsA, in spite of the increasing trends of AUC(0-48 h) and C(max). After high dose TMP pretreatment and co-administration with CsA, AUC(0-48 h) and C(max) of CsA were increased significantly (P < 0.01), but there was no significant change in other parameters.

CONCLUSION

It was indicated that the high dose of TMP could apparently increase the intragastric absorption extent of CsA, while almost had no effect on its elimination process.

[Effects of D-limonene and L-limonene on transdermal absorption of ligustrazine hydrochloride]

AIM

To investigate the effects and permeation mechanism of D-limonene and L-limonene on transdermal delivery of ligustrazine hydrochloride (LH).

METHODS

Transdermal flux of LH through porcine skin was determined in vitro by Franz-type diffusion cells. The peak shift and peak areas of C-H stretching vibration absorption were estimated by Fourier transform-infrared (FTIR). Morphological changes in the stratum corneum (SC) treated with enhancers were observed by a scanning electron microscope (SEM) and apparent density, a new concept, was proposed to estimate the desquamated extent of SC for the first time.

RESULTS

There were no statistic difference (P > 0.05) between the transdermal fluxs of the enantiomer enhancers which were higher than those of control and azone. But the lag time of L-limonene was 2.55 times than that of D-limonene. The FTIR results revealed that the shift and decreased peak area of C-H stretching vibrations in the SC lipids were dependent on the enhancers. The enantiomers permeation enhancers, D-limonene and L-limonene, were able to perturb and extract the SC lipids to different extent. The disordering and extracting lipids activity of L-limonene was stronger than that of D-limonene. SEM studies demonstrated that the extraction of lipids was depended on the selected penetration promoters.

CONCLUSION

D-limonene was the most effective enhancer which had the greater transdermal flux of LH and the least lag time. The results showed that the permeation enhancement mechanism of the enantiomer enhancers to LH was multiple ones including disordering and extracting the SC lipids and probably including stereoselective mechanism.

Tetramethylpyrazine production from glucose by a newly isolated Bacillus mutant

2,3,5,6-Tetramethylpyrazine (TTMP) was produced using a newly isolated Bacillus mutant. Culture medium optimization studies showed that soytone, an enzyme-hydrolysate of soybean meal, with the supplementation of vitamins, can fully replace yeast extract plus peptone in supporting TTMP production from glucose. In a 5-l fermenter, using the optimized medium which contained 20% glucose, 5% soytone, 3% (NH(4))(2)HPO(4), and vitamin supplements, fermentations were carried out with stirring at 700 rpm, air flow at 1.0 vvm, controlled pH at 7.0, and temperature at 37 degrees C. TTMP reached 4.33 g l(-1) after 64.6 h cultivation. A product recovery method was described, which involved evaporation, crystallization, and lyophilization. The product purity was 99.88%, determined by GC with the normalization method. The main impurities were 2,3,5-trimethylpyrazine (0.09%) and 2-ethyl-3,5,6-trimethylpyrazine (0.02%), which were identified by GC/MS. (13)C NMR determination also gave a consistent result. Natural and high purity of the product and the utilization of cheap green renewable materials make this process promising to compete with TTMP chemical synthetic methods.

[Protective effects of ligustrazine against photoreceptor cell injury induced by N-methyl-N-nitrosourea and its mechanism]

AIM

To study the protective effect of ligustrazine against photoreceptor cell injury induced by N-methyl-N-nitrosourea (MNU) in Sprague-Dawley (SD) rats.

METHODS

Ligustrazine injections of different doses were injected intraperitoneally into 47-day female SD rats once a day and a single intraperitoneal injection of MNU 60 mg x kg(-1) was given to 50-day rats. At different intervals after MNU treatment,the animals were sacrificed. The apoptotic index of photoreceptor cells was calculated by TUNEL labeling at 24 h following MNU treatment; peripheral retinal damage was evaluated based on retinal thickness at the d 7 after MNU treatment, and the expression of c-jun and c-fos genes was detected by RT-PCR technique.

RESULTS

Ligustrazine injection could remarkably increase total thickness of peripheral retina and decrease apoptotic index of photoreceptor cells induced by MNU in a dose-dependent manner. Compared with MNU-treated rats, the gene expression of c-jun and c-fos was time-dependently down-regulated in ligustrazine-treated group.

CONCLUSION

Ligustrazine injection partially protects against MNU-induced retinal damage by down-modulating the expression of c-jun and c-fos genes to inhibit apoptosis of photoreceptor cells.

Tetramethylpyrazine protected photoreceptor cells of rats by modulating nuclear translocation of NF-kappaB

AIM

To evaluate the effect of tetramethylpyrazine (TMP) injection on retinal damage induced by N-methyl-N-nitrosourea (MNU) in rats and on nuclear factor-kappa B (NF-kappaB) family members.

METHODS

Female Sprague-Dawley (SD) rats were randomly divided into groups: (i), control group; (ii), model group; and (iii), TMP-injection groups, in which the rats were subdivided into 40 mg/kg, 80 mg/kg and 160 mg/kg groups. Drugs were injected ip into 47-day-old SD rats once a day. At 50 days of age, all rats in the model group and drug groups also received a single ip injection of 60 mg/kg MNU. Rats in group 1 received ip injection of physiological saline. All rats were killed at different times after MNU or physiological saline treatment. The apoptotic index of photoreceptor cells was calculated by TUNEL labeling; retinal damage was evaluated based on retinal thickness and the expression of NF-kappaB family members was detected by Western blot.

RESULTS

TMP injections, in a dose-dependent manner, suppressed photoreceptor cell apoptosis and decreased its loss in the peripheral retina. As compared with the MNU-treated group, TMP injection at a dose of 160 mg/kg also time-dependently upregulated the NF-kappaB/p65 protein level in the nucleus and downregulated the IkappaBalpha protein level in the cytoplasm. However, no protective effect of TMP injection on MNU-induced central retinal damage was found.

CONCLUSION

TMP injection partially protects against MNU-induced retinal damage by upregulating the nuclear translocation of p65 to inhibit photoreceptor cells apoptosis.

The Chafer Pheromone Buibuilactone and Ant Pyrazines are also Produced by Marine Bacteria

Headspace extracts obtained from agar plate cultures of two marine bacteria from the North Sea (Germany), Loktanella strain BIO-204 and Dinoroseobacter shibae strain DFL-27, were analyzed by GC-MS. Several gamma-lactones and one delta-lactone were identified, besides pyrazines and some sulfur compounds. The absolute configuration of the major lactone (R,Z)-dodec-5-en-4-olide, known as buibuilactone, a pheromone of several scarab beetles, was determined by a new catalytic enantioselective synthesis and GC on a chiral stationary phase. Unsaturated lactones in the extracts included (E)-dodec-5-en-4-olide and the regioisomer (Z)-dodec-6-en-4-olide, previously identified as a component of black-tailed deer urine. The pyrazines 2-butyl-3,6-dimethylpyrazine and 2-isopentyl-3,6-dimethylpyrazine were identified by comparison with synthesized material. The latter compound is a known ant pheromone, as is another identified pyrazine, 2-ethyl-3,6-dimethylpyrazine. The striking similarity between insect pheromones and these bacterial volatiles is discussed, suggesting the possibility of more widespread occurrence of symbiosis between microorganisms and insects than previously thought.

Preparative isolation and purification of chuanxiongzine from the medicinal plant Ligusticum chuanxiong by high-speed counter-current chromatography

Ligusticum chuanxiong Hort has been used widely in traditional medicines for the treatment of various kinds of disorders such as cardiovascular and cerebrovascular diseases. High-speed counter-current chromatography was applied to the isolation and purification of the bioactive component chuanxiongzine from L. chuanxiong Hort. The crude chuanxiongzine was obtained by extraction with ethanol from the dried roots of L. chuanxiong Hort under sonication. Preparative high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (5:5:3:7, v/v) was successfully performed yielding 11.5 mg chuanxiongzine at 96.8% purity from 300 mg of the crude extract (4.2% chuanxiongzine) with the recovery of 91% in a one-step separation.

Removal of earthy-musty odorants in drinking water by powdered activated carbon

The removal of four earthy-musty compounds, 2-methylisoborneol (MIB), 2,4,6-trichloroanisole (TCA), 2-isopropyl-3-methoxy-pyrazine (IPMP), and 2-isobutyl-3-methoxy-pyrazine (IBMP), by powdered activated carbon (PAC) were investigated under the simulative condition of Xicun water plant, Guangzhou. The adsorption kinetics of odor compounds by two PACs show that main removal of odor compounds occurs within contact time of 1 h. Compared with the wood-based PAC, the coat-based PAC evidently improves the removal efficiency of poorly adsorbed compounds like MIB. The effects on removal efficiency such as optimum PAC dosage, initial concentration of the organics, chlorine residual, background organics, and changes of water quality were investigated. The percent removal of trace odorants at any given time for a particular carbon dosage is irrelative to the initial concentration of the odor compounds. Adsorptive capacity of PAC for target compounds is reduced by chlorine residual and background organics. Characteristics of raw water have vast influence on the removal of target compounds by PAC.

[Study on the interactions between four components in Ligusticum chuanxiong rhizome and acceptors on cardiac muscle membrane]

OBJECTIVE

To study the interactions between four components in Ligusticum chuanxiong rhizome and heart cell membrane acceptors.

METHOD

Through observing the retention characteristics of the four components (tetramethylpyrazine, vanillic, chrysophol, ferulic acid) on cell membrane stationary phase (CMSP) chromatographic column, whether the components combine with cell membrane acceptors was studied, and through further comparing the retention characteristics with those of known activators or antagonists corresponding to cell membrane acceptors, the kind of acceptor with which one component combines was studied.

RESULT

Tetramethylpyrazine, vanillic and chrysophol had retention on CMSP chromatographic column while ferulic acid hadn't. The retention characteristics of tetramethylpyrazine were similar to activator and antagonist corresponding to a acceptor, vanillic with beta1 acceptor activator.

CONCLUSION

Tetramethylpyrazine, vanillic and chrysophol can all combine with cardiac muscle membrane acceptors, while ferulic acid can not; tetramethylpyrazine probably acts on a acceptor and vanillic acts on beta1 acceptor.

[Effect of ligustrazine on injury of vascular endothelial cells ECV-304 induced by hypoxia and lack of glucose]

OBJECTIVE

To investigate the effects of ligustrazine on nitric oxide (NO), malonaldehyde (MDA) production, release of intracellular lactate dehydrogenase (LDH) and membrane fluidity of the injured human umbilical vein vascular endothelial cell line (ECV-304) with hypoxia and lack of glucose.

METHOD

The experiments were performed in culture of ECV-304 injured with hypoxia and lack of glucose in vitro. The released LDH of ECV-304 was measured with automatic biochemistry analyse. NO content of ECV-304 was monitored with colorimetry. Lipid peroxidation of ECV-304 was monitored as MDA with a fluorometric assay. The membrane fluidity of ECV-304 was measured with the fluorescence polarization method.

RESULT

After culture ECV-304 in hypoxia and lack of glucose for 24 h, the LDH release, MDA production and the membrane fluidity increased significantly and NO level was decreased. Preincubation of ECV-304 with ligustrazine for 24 h reduced LDH release, MDA production, membrane fluidity increasing and increased the level of NO in ECV-304 due to hypoxia and lack of glucose.

CONCLUSION

Ligustrazine has protective effect on injury of ECV-304 induced by hypoxia and lack of glucose.

[Effect of ligustrazine on proliferative glomerulonephritis]

OBJECTIVE

To investigate the therapeutic effect of ligustrazine on proliferative nephritis.

METHODS

45 patients with mesangial cell proliferation were randomly divided into two groups according to age, clinical manifestations and the pathological lesions. Steroid, cyclophosphamide, losartan and dipyridamole were given to 20 patients in the control group. Ligustrazine with the dosage of 80 mg twice a day was given to 25 patients in the treatment group by intravenous perfusion besides the medicine used in the control group. The course of ligustrazine treatment lasted three weeks.

RESULT

The proteinuria and hematuria were decreased significantly with the increases of urine volume, serum albumin and creatinine clearance after ligustrazine treatment. The improvement of serum albumin, proteinuria and hematuria in the treated group were significant compared with control group after treatment.

CONCLUSION

Ligustrazine is eutherapeutic in treating proliferative glomerulonephritis, with the less risk of hemorrhage, ligustrazine can be used for long-term treatment without special monitored.

A new 1-hydroxy-2,6-pyrazinedione associated with hypovirulent isolates of Sclerotinia minor

A new 1-hydroxy-2,6-pyrazinedione, sclerominol (1), was isolated from cultures of hypovirulent isolates of Sclerotinia minor, a fungal plant pathogen associated with lettuce drop and other plant diseases. This compound was characterized by NMR, mass spectrometry, and X-ray crystallography. One other 1-hydroxy-2,6-pyrazinedione, flutimide, has been reported. Flutimide has activity as an inhibitor of influenza virus endonuclease, and therefore, sclerominol was evaluated for related biological activity. Sclerominol (1) displayed some activity against cancer cell lines but little activity against three influenza virus strains. The role of 1 in the physiology of hypovirulent isolates of S. minor has not been determined, but 1 has also been recovered from debilitated isolates of S. sclerotiorum.

Pharacine, a natural p-cyclophane and other indole derivatives from Cytophaga sp. strain AM13.1

From the ethyl acetate extract of the bacterial strain Cytophaga sp. AM13.1, among many known compounds, the new natural products 2,5-bis(3-indolylmethyl)pyrazine (2) and a highly symmetrical p-cyclophane named pharacine (5) were identified. In addition, tryptamine isovalerate (1) and p-hydroxyphenylacetamide (4), known as plant metabolites, were isolated and characterized from a microorganism for the first time. The new natural products showed no activity against three microalgae, the fungus Mucor miehei, the yeast Candida albicans, and the bacteria Staphylococcus aureus, Bacillussubtilis, Escherichia coli, and Streptomyces viridochromogenes.

New convulsive compounds, brasiliamides A and B, from Penicillium brasilianum batista JV-379

New convulsive compounds, brasiliamides A (1) and B (2), were isolated by activity-guided fractionation from okara fermented with a soil isolate of Penicillium brasilianum Batista JV-379. Their structures were elucidated on the basis of spectral and chemical evidence and by X-ray crystallography of the hydrogenated product of 2. In the 1H- and 13C-NMR spectra of 2, the signals were complicated, all being doubled or broadened in several deuterated solvents at room temperature. The conformational change of 2 was clarified as the rotational isomerization of amide bonds in solution by NMR measurements at various temperatures. Four rotamers of 2 at two amide bonds were presented at -60 degrees C in CDCl3, whereas only two isomers were apparent at room temperature, owing to rapid rotation of one of the amide bonds. Brasiliamides A and B respectively showed convulsive activity against silkworms with ED50 values of 300 and 50 microg/g of diet.

Current studies on anti-endotoxic chemical components of traditional Chinese medicine in China

Endotoxin (ET) was found to have wide bioactivities and ET antagonists have become the pop research topic in life science. The chemical components of traditional Chinese medicine (TCM) were the substance basis of its pharmacology. This review demonstrated the study state of about 18 chemical components from TCM, eg, organic acids of Radix Isatidis, anisodamine, matrine, tetramethypyrazine, colchicine, and glycine, etc, which showed anti-endotoxin effects through different routes. But now the most of them were limited to the laboratory. In the future, the trends of development should not only enlarge the range of research, but also strengthen the clinical study.