Establishment of a Colloidal Gold Immunochromatographic Method for the Detection of Cypermethrin in Tobacco.

In this study, the establishment of a colloidal gold immunochromatographic method for the detection of cypermethrin in tobacco was achieved by using colloidal gold immunochromatography: strong specificity and high sensitivity of cypermethrin semi-antigens and encapsulants were prepared during the study. The best colloidal gold solution was prepared by spectrophotometer and transmission electron microscope screening; the preparation process of gold-labeled antibodies was optimized, and finally the product of colloidal gold rapid detection test strips for cypermethrin was developed. The results of technical parameters and detection indexes showed that the detection limit of cypermethrin in tobacco was 1 mg/kg, and there was no cross-reaction with bifenthrin, cypermethrin, cyfluthrin and phenothrin, and the detection results of 30 tobacco samples were consistent with those of gas chromatography.

Development of Colloidal Gold Test Strips for the Detection of Oxamyl Residues in Tobacco.

In this study, monoclonal antibodies against oxamyl were prepared, and colloidal gold immunochromatography was used to design a rapid test strip product for the detection of oxamyl in tobacco with high specificity, accuracy and stability without cross-reactivity to commonly used tobacco fungicides based on the optimization of conditions such as pH value of diluent, diluent dosage, concentration of antibody marker, type of confining solution and complex solution. 5 The results of five samples of post-harvest ready-to-bake tobacco and first-harvest tobacco were consistent with the gas chromatographic method, which proved the reliability of the test strips. The limits of detection for the post-harvest and first-harvest tobacco samples were 0.1 mg/kg, and the test strips developed in this study are suitable for mass testing in tobacco laboratories with good application prospects because of their short detection time, simple pre-treatment and detection methods.

Development of Colloidal Gold Test Strips for the Detection of Triadimenol Residues in Tobacco.

The rapid and accurate determination of triadimenol residues is of great significance. In this study, based on the advantages of high efficiency, rapidity, reliability, simplicity and low cost of immunology, a test strip product for the rapid detection of triadimenol residues in tobacco was designed based on the optimization of conditions such as pH and dosage of diluent, concentration of antibody stock solution, type of confining solution and complex solution, with high specificity, accuracy and The results of 20 samples of fresh and first roasted tobacco were all consistent with the method of gas chromatography, which proved the reliability of the test strips. The detection limit for fresh and roasted tobacco was 5 mg/kg, and the test strips developed in this study are suitable for mass testing of tobacco samples in tobacco-related laboratories because of their short detection time, simple pre-treatment and detection methods, and good application prospects.

Two new ent-atisane diterpenes from Sapium sebiferum.

Two new ent-atisane diterpenes, sebiferumnins K and L (1 and 2), were isolated from the branches of Sapium sebiferum, together with four known compounds, ent-3-oxoatis-16α, 17-acetonide (3), ent-l6α, 17-dihydroxyatisan-3-one (4), ent-atisane-3ß, 16α, 17-triol (5), ent-3α-hydroxyatis-16α,17-acetonide (6). The structures of these two ent-atisane diterpenes were elucidated by extensive analyses of the spectroscopic data. [Formula: see text].

New Sweet-Tasting Oleanane-Type Triterpenoid Saponins from "Tugancao" (Derris eriocarpa How).

With the aim to investigate the sweet-tasting compounds in Derris eriocarpa How (a substitute for licorice in "Zhuang" and "Dai" ethnopharmacy in Guangxi and Yunnan provinces of China) as well as to ascertain why the stem of D. eriocarpa can be used to substitute for licorice in the sweetness taste aspect, taste sensory-guided fractionation was conducted to isolate sweet constituents from the extract of D. eriocarpa. Four sweet-tasting triterpenoid saponins were obtained, including millettiasaponin A (1) and three new saponins named derrisaponins A-C (2-4). The sweetness potency was evaluated by a human sensory panel test. The sweetness intensities of compounds 1-4 were determined to be approximately 150, 80, 2, and 0.5 times relative to sucrose at the concentration of 1%, respectively, of which compounds 1 and 2, with a free carboxyl group at the C-30 position, showed more potent sweetness intensity. In addition, compounds 1 and 2 showed no acute toxic activity at doses of 250 and 400 mg/kg of body weight, respectively, assessed through caudal vein injection to ICR mice. The contents of the sweetest compounds in stems were analyzed quantitatively as 352.80 mg/kg for compound 1 and 1887.60 mg/kg for compound 2 performed by ultra-performance liquid chromatography-tandem mass spectrometry.

Antibacterial and antioxidant properties of crude extract, fractions and compounds from the stem bark of Polyscias fulva Hiern (Araliaceae).

BACKGROUND: In our previous work, the dichloromethane-methanol (1:1 v/v) extract, fractions and isolated compounds from Polyscias fulva stem bark showed interesting antifungal activity. As a continuity of that work, this study aimed to bring out complementary informations about the antimicrobial properties of P. fulva stem bark that may be useful in the standardization of phytomedicine from this plant. METHODS: The antibacterial activities of the crude extract, fractions (n-hexane, ethyl acetate, n-butanol and residual) and isolated compounds from Polyscias fulva stem bark were assayed by broth microdilution techniques. Their antioxidant activity were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), pyrogallol (superoxide anion) and ß-carotene - linoleic acid assays. RESULTS: The crude extract presented antibacterial activities against S. typhi (ATCC 6539), E. aerogenes (ATCC 13045), P. aeruginosa (PA01) and E. coli (ATCC 10536) with MIC values of 2000 to 8000 µg/ml. The fractionation led the ethyle acetate and n-butanol fractions relatively more active (MIC = 500 to 1000 µg/ml) as compared to the crude extract. ß-sitosterol and 3-O-α-L- arabinopyranosyl-hederagenin were the most active compounds on the tested bacteria with MIC values ranging from 6.25 to 100 µg/ml. The most sensitive was P. aeruginosa (PA01) on which all the tested compounds were active with MICs ranging from 6.25 to 400 µg/ml. Among all the tested substances, the crude extract (RSa50 = 84.86 µg/ml) and the methyl atrarate (RSa50 = 14.77 µg/ml), showed the highest scavenging activities against DPPH free radicals and those arising from the oxidation of the linoleic acid respectively. CONCLUSION: From this study, the results obtained reveal that the stem bark of P. fulva possesses antibacterial and antioxidant activities. It may then be useful in the development of an antimicrobial phytomedicine with a large spectrum of actvity endowed with antioxidant properties which can be standardised based on the isolated compounds.

New antimicrobial pregnane glycosides from the stem of Ecdysanthera rosea.

Phytochemical investigation on the stem of Ecdysanthera rosea led to the isolation of eight new C-21 pregnane glycoside ecdysosides A-H (1-8), together with one known pregnane glycoside ecdysantheroside A (9). Their structures were elucidated based on extensive spectroscopic data (MS, IR, 1D and 2D NMR) analysis, as well as comparison with the reported literature data. Antimicrobial activities of all the compounds were evaluated against bacteria and yeasts. Compounds 1, 9, 3 and 5 exhibited moderate antibacterial activities against respective Enterococcus faecalis and Providensia smartii, with MIC value of 12.5 µg/mL. Compound 8 showed significant anti-yeast activity against Cryptococcus neoformans with MIC value of 12.5 µg/mL.

Fragrant volatile sesquiterpenoids isolated from the essential oil of Laggera pterodonta by using olfactory-guided fractionation.

Chemical composition of the essential oil from Laggera pterodonta (Compositae) was inverstigated. GC/MS Analyses led to the identification of 68 components, representing more than 96% of the total oil. By focusing on the woody note fraction of the essential oil, one new bisabolane-type sesquiterpenoid, bisabola-2,7(14),11-trien-10-ol (1), together with ten known compounds, bisabolol oxide B (2), ylangenol (3), copaborneol (4), guai-11-en-10-ol (5), spathulenol (6), aromadendran-10-ol (7), caryophyllenol (8), 5α,7α-eudesm-11(13)-en-4α-ol (9), γ-costic acid (10), and eudesma-4(15),11(13)-diene-12,5ß-olide (11), were isolated by using olfactory-guided fractionation. The structures of the eleven compounds were determined by NMR and MS analyses. All the volatile compounds reported here were isolated for the first time from this plant. On the basis of preliminary odor assessment, the odor of the woody-note fractions of the essential oil was assumed to be due to these isolated sesquiterpenoids.

Chemical composition and antimicrobial activity of the essential oil from the edible aromatic plant Aristolochia delavayi.

The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)-dec-2-enal (52.0%), (E)-dodec-2-enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 µg/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 µg/ml, while (E)-dec-2-enal presented a lower antifungal activity than the essential oil.

[Study on the degradation of phenol wastewater using hydroxyl radical produced by plasma and the course by UV spectra].

The phenol wastewater with high concentration was treated by hydroxyl radical produced by a strong ionization discharge plasma in the present article. Salicylic acid used as molecular probe to determine the concentration of hydroxyl radical. The phenol elimination efficiency of wastewater whose initial concentration was 1 21 5 mg x L(-1) could reach 99.11% when the concentration of hydroxyl radical was 1 037 mg x L(-1); while the initial concentration of 8 853 mg x L(-1) of phenol wastewater dropped to 6 250 mg x L(-1) under the same conditions, that is, 1 mg hydroxyl radicals could oxidize 2.5 mg of phenol. The smaller the initial phenol concentration, the higher the removal. However, the higher the initial concentration, the greater the absolute quantity of treatment. And the relation between the changes including pH value and the conductivity and the concentration of hydroxyl radical was stated and explained. With the concentration of hydroxyl radicals increasing, the pH value of wastewater changed from close to neutral to acidity gradually. The higher the concentration of hydroxyl radical, the stronger the acidity of wastewater. When continuing the increase in the concentration of hydroxyl radical, the change began to smooth. With the addition of hydroxyl radical, as is different from other phenomena, there was a tiny descending stage before ascending as shown on the conductivity curve, indicating that phenol had been oxidized and generated the organic acids continuously. Catechol, hydroquinone and benzoquinone are the important compounds of the intermediate products as shown by the analysis of UV spectra and chromatography. The final UV spectra curve indicated that there were little organic compounds containing conjugated structure in the treated wastewater.

[Overproduction of glucoamylase by recombinant Aspergillus niger harboring multiple copies of glaA].

The glucoamylase gene (glaA) of Aspergillus niger CICIM F0410 was cloned, sequenced and expressed. The integrated plasmid pBC-Hygro-glaA carrying the glaA was constructed and transformed into A. niger F0410. Transformants with multiple copies of glaA integrated in the chromosome were selected by 150 microg/mL hygromycin B and identified by real-time PCR. Two to three multiples of glaA in the chromosome were found to be optimal for higher expression of glucoamylase. Shake-flask fermentation under optimal conditions showed that glucoamylase secreted by the transformant GB0506 was 17.5% higher than parental strain F0410 at the end of fermentation. In conclusion, increasing copy number of glaA by chromosomal integration significantly improves the yield of glucoamylase in the industrial strain of A. niger.