Advanced Materials Research Vols. 550-553

Abstract: This paper describes a new kind of 9-residue half-sequence ionic-complementary peptide P-X7-P, which can spontaneously self-assemble into well-ordered and long interconnected nanofibrilar network structure in pure water, and can be used as a hydrophobic compounds carrier. Psoralen, a natural product, is slight water soluble but has various treatments in medicine. In order to fully understand the interaction between the self-assembling peptide and psoralen,the nanostructures formed by two of them were characterized by atomic force microscopy (AFM), field-emission scanning electron microscopy (FE-SEM). This work provides insights on the interaction between the amphiphilic self-assembling peptide and psoralen that are useful for the bottom up development of peptide sequence for local natural product drug delivery applications.

Abstract: AIM：To investigate the chemical constituents of Illicium dunnianum. METHODS: Compounds were isolated and purified by carious chromatographic techniques and their structures were elucidated by physicochemical and spectral data. RESULTS: Eleven known compounds were isolated and identified as (2R, 3R)-3, 5, 7, 3', 5'-pentahydroxyflavan (1), epicatechol (2), pinocembrin (3), (2R, 3R)-3, 5, 7, 3′, 4′-pentahydroxyflavan (4), (-)-epiafzelechin (5), quercetin-3-O-α- L-rhamnoside(6), methyl 2,5-dihydroxybenzoate (7), gallic acid (8), shikimic acid (9) and ethyl shikimate(10) and 4,5-Dimethoxy-6-(2-propenyl)-1,3-benzodioxole(11). CONCLUSION: Compound 1-8, 10 and 11 were isolated from this plant for the first time.

Abstract: N-nitrosamine is a kind of carcinogenic substance, which is possibly formed in the reaction of nitrites with amino acids or secondary amines. Two in vitro model systems were designed to evaluate the influence of oxidized myofibrils protein subjected to repeated freeze-thaw cycles (0, 1, 2, 3, 4, 7, 10 times) on N-nitrosamine formation. Model system I contains diethylamine and sodium nitrite, while model system II contains only sodium nitrite as reaction solution. Oxidized myofibrils protein were added to both systems. The results revealed that as the number of freeze-thaw cycles increased, cross-linking of myosin heavy chains and the content of protein carbonyl increased, but the content of protein sulfydryl decreased, which indicates oxidization of protein occurred. The concentration of N-nitrosodiethylamine increased as the number of freeze-thaw cycles increased, especially after four cycles. Oxidized myofibrils protein promoted the formation of N-nitrosodiethylamine. The more the times of freeze-thaw cycles were subjected, the more oxidization of myofibrils protein occurred and the higher yield of the N-nitrosodiethylamine.

Abstract: To extend the application of the thermally unstable pigments from Phytolacca americana L.’s fruits on textiles, the thermal degradation kinetics and thermodynamics of pigments in solution have been studied and taken into account in dyeing processes. The experimental datas of the thermal degradation kinetics, thermodynamics and dyeing kinetics have been analyzed using First Order Reaction Kinetics, Arrhenius Equation, and Vickerstaff Adsorption Hyperbolic Curve theories, respectively. The results indicate that, the Vickerstaff Adsorption Hyperbolic Curve theories can be used to describe the dyeing adsorption kinetics of the pigments dyed on mercerized wool yarns taking thermal degradation into consideration. The values of half-time, rate constant of thermal degradation, equilibrium dyeing percentage, adsorption constant, dyeing time, dyeing temperature and others parameters also have been analyzed in this article. The appropriate dyeing time and dyeing temperature for the pigments dyed on mercerized wool yarns have been found out.

Abstract: The ability to decorate silicate surface with different organoalkoxysilanes creates powerful new capabilities for catalyst, adsorbents and chemical separation. Mesopororus silica, MCM-41 was modified by grafting of amino and mercaptopropyl functional group. The structures of these materials were characterized by using Fourier Transform Infrared Spectroscopy (FT-IR), and X-Ray diffraction (XRD). The samples were found to exhibit structural properties similar to those reported earlier. Significant functional groups of the modified mesoporous silicates were found in the spectrum of FT-IR. Standard structure of mesoporous silicates were found to be preserved at planar [100] of XRD difractogram of mesoporous silicates. Adsorption of Cu (II) ions were done under different temperatures, initial concentrations and pH. Adsorption process also was determined from kinetic point of view and was found to be better fitted to pseudo second order of kinetic model.

Abstract: Using amino nitrogen content ( AN for short ) as standards, the conditions of low molecular weight polypeptides with three kinds of enzymes hydrolysis as well as the sequence and way of adding enzymes with microwave heating was found in this paper, which was examined by fluorescence analysis method, seperated by Sephadex G-50. The result shows that three kinds of enzymes hydrolysis were prefer to one enzyme obviously, amino nitrogen was higher for 2813.4 mg/L, the relative molecular mass of soybean polypeptides was mostly below 1000 D. Soybean polypeptide was well tested and seperated by Sephadex G-50 and fluorescence analysis method.

Abstract: We isolated 6 bacterial cellulose-production strains from the natural decay of a variety of different types of fruit with sucrose as carbon, peptone and yeast extract as nitrogen sources in the 30 º C, pH = 6.0 by enrichment culture and diluted coating. M7, one of the screened strains from mango, yield the highest yield bacterial cellulose of wet weight 66.01g/100ml (cellulose g/100ml medium) and the production of cellulose film thickness 1.65cm in course of subculturing.

Abstract: Pseudomonas sp. B3-1, a wild strain isolated from soil, produced catechol from benzoate and accumulated it outside the cell. catA, a gene encodes a catechol 1,2-dioxygenase in the bioconversion of aromatic compounds, plays the central role in accumulation of catechol. Mutant of the catA gene is disrupted without blocking the transcription of downstream genes was analyzed. The result showed that the mutant had less catechol 1, 2-dioxygenase activity, only 1/3 of strain B3-1’s. The mutant produced a maximal amount of catechol (1.22 mg/ml) from 4 mg/ml of sodium benzoate after growing for 48 h. The conversion rate of benzoate to catechol was 51.5% on a molar basis.

Abstract: Solanesol is an important pharmaceutical intermediate. In this paper, organic solvent is used to extract solanesol from the abandoned tobacco. The conditions of extracting the solanesol are optimized, such as extraction solvent, solvent ratio, extraction temperature and time. The extraction times are also identified. L9(34) design is selected to investigate the factors above. Finally, the optimal extraction conditions are proposed. The petroleum ether is used as solvent, the solvent ratio is 15:1(volume of solvent is 15ml, quality of leaves is 1g), the extraction temperature is 50°C and the time is 4h. The purity of solanesol reaches to 57.56% and the total yield reaches to 6.39%.

Abstract: To optimize the extraction process of total flavonoids from RADIX RHIZOMA GLYCYRRHIZAE and Study on the Antioxidant Activity. Total flavonoids were extracted from RADIX RHIZOMA GLYCYRRHIZAE with ethanol by ultrasonic-assisted method, whose extraction process was optimized by orthogonal test design.The scavenging effect of pumpkin polysaccharide on OH and O2-were studied by salicylic acid and pyrogallic acid method. The optimum extraction process was as follows: ethanol concentration of 75%, solid-liquid ratio of 1:25,ultrasonic power of 350 W and ultrasonic duration of 25 min.Under the above conditions, the extraction rate of total flavonoids reached as high as 1.943%. The influencing order of each factor on extraction rate of polysaccharides was determined to be: ethanol concentration＞solid-liquid ratio＞ultrasonic power＞ultrasonic duration. When the solution concentration is 1.1296mg/ml, the scavenging rate of crude flavonoids on superoxide radical is 50%.Suggesting that it would be an effctive natural free radical scavenger. The study could provide a scientific basis for the further exploitation and utilization of RADIX RHIZOMA GLYCYRRHIZAE