Anti-tumor activity of triterpenoid-rich extract from bamboo shavings (Caulis bamfusae in Taeniam)

Bamboo shavings are a kind of Chinese traditional medicine, which have been certificated as a material of functional food by the Ministry of Health in China. The anti-tumor activities of a triterpenoid-rich extract of bamboo shavings (EBS) and its main component, friedelin were evaluated in the present study. It was proved that EBS could inhibit the growth of P388 and A549 cancer cell lines effectively by SRB and MTT assay. Meanwhile, EBS had notable inhibitory effect on the sarcoma-loaded mice S180 model, which led to a depressed trend of tumor weight, compared to cyclophosphamide. Furthermore, the anti-tumor activity of friedelin monomer, a main triterpenoid separated from EBS, was tested by MTT assay and results showed that friedelin displayed rather strong anti-tumor activities on the proliferation of four cancer lines, A375, L929, Hela and THP-1, with a time-dose relationship compared to de-methylcantharidin, respectively. Therefore, it is suggested that EBS has a great potential to be applied in functional food for its anti-tumor activity, in which friedelin was one of the most important active factors

Construction of Quality Index System and Screening of Characteristic Index of Rice for Different Uses

Taking rice as the object of study, this study systematized quality evaluation indicators, assessment methods, and their foundations, constructing a rice quality indicator system tailored to different uses. It explored the quality variances among rice from different premier production regions and primary cultivars, identifying distinctive quality indicators for rice suited to specific uses, with the goal of standardizing the quality assessment of rice. The Delphi and G1 methods were applied to distill key quality indicators from a broader set, culminating in the development of a structured quality indicator system. The study assessed the differences in essential quality indicator components across 262 rice samples. Techniques such as correlation analysis, principal component analysis, and multiple linear regression analysis were utilized to pinpoint characteristic quality indicators tailored to the intended use of the rice. The results showed that the dominant producing areas of rice for edible commercial rice were the rice dominant areas in northeast China (Liaoning, Jilin) and the rice dominant areas in the Yangtze River basin (Jiangsu), high quality varietiesare, Shennong 511, Jijing 816, Nanjing 46, and the characteristicquality indicators were food taste value, protein, smell. The dominant producing areas of rice for rice noodles processing were the southeast coastal areas (Guangdong, Guangxi, Zhejiang) and the Yangtze River basin (Hunan), high-quality varieties were Zhongzao 39, Xiangzao Xian 45, Zhengui, and Chunliangyou 61, and the characteristic quality indexes were the peak viscosity, final viscosity, protein content and amylose content. The dominant producing areas of rice for fermentation products were the southeast coastal areas (Zhejiang) and the Yangtze River basin (Jiangxi, Hunan), high-quality varieties were Zhongzao 39, Zhongzao 33, and Xiangzao Xian 45, and the characteristic quality indexes were the amylose content, saccharification property and reducing sugar content. The results of this study provide a theoretical basis and scientific basis for the quality evaluation of rice for different purposes

Construction of Quality Evaluation Systems for Coffee Beans and Their Application to Chinese Coffee Beans

In order to explore quality evaluation methods for Chinese coffee beans for freshly ground coffee and instant coffee and to select evaluation indicators, the major quality indicators were selected from the basic quality indicators through the Delphi evaluation method and sequence relationship analysis to construct a quality index system. Then the differences in the major quality indicators of 53 coffee bean samples from different production areas in Yunnan and Hainan provinces were determined, the characteristic quality indicators of coffee beans for different purposes were selected by correlation analysis, principal component analysis (PCA) and cluster analysis, and stepwise multiple linear regression analysis was conducted based on the comprehensive scores of the principal components of the samples. Finally, grain size, taste, aroma and carbohydrate content were selected as the characteristic quality indicators of instant coffee and grain size, taste, aroma and caffeine content as the characteristic quality indicators of freshly ground coffee. It is determined that the major varieties suitable for instant coffee are Catimor and Typica, and the major production area is Yunnan province. The major variety suitable for freshly ground coffee is Catimor, and the major production area is Yunnan province

Molecular Dynamics Analysis Reveals Structural Insights into Mechanism of Nicotine N-Demethylation Catalyzed by Tobacco Cytochrome P450 Mono-Oxygenase

CYP82E4, a cytochrome P450 monooxygenase, has nicotine N-demethylase (NND) activity, which mediates the bioconversion of nicotine into nornicotine in senescing tobacco leaves. Nornicotine is a precursor of the carcinogen, tobacco-specific nitrosamine. CYP82E3 is an ortholog of CYP82E4 with 95% sequence identity, but it lacks NND activity. A recent site-directed mutagenesis study revealed that a single amino acid substitution, i.e., cysteine to tryptophan at the 330 position in the middle of protein, restores the NND activity of CYP82E3 entirely. However, the same amino acid change caused the loss of the NND activity of CYP82E4. To determine the mechanism of the functional turnover of the two molecules, four 3D structures, i.e., the two molecules and their corresponding cys–trp mutants were modeled. The resulting structures exhibited that the mutation site is far from the active site, which suggests that no direct interaction occurs between the two sites. Simulation studies in different biological scenarios revealed that the mutation introduces a conformation drift with the largest change at the F-G loop. The dynamics trajectories analysis using principal component analysis and covariance analysis suggests that the single amino acid change causes the opening and closing of the transfer channels of the substrates, products, and water by altering the motion of the F-G and B-C loops. The motion of helix I is also correlated with the motion of both the F-G loop and the B-C loop and; the single amino acid mutation resulted in the curvature of helix I. These results suggest that the single amino acid mutation outside the active site region may have indirectly mediated the flexibility of the F-G and B-C loops through helix I, causing a functional turnover of the P450 monooxygenase

Thermoelectric Generation Using Counter-Flows of Ideal Fluids

Thermoelectric (TE) performance of a three-dimensional (3-D) TE module is examined by exposing it between a pair of counter-flows of ideal fluids. The ideal fluids are thermal sources of TE module flow in the opposite direction at the same flow rate and generate temperature differences on the hot and cold surfaces due to their different temperatures at the channel inlet. TE performance caused by different inlet temperatures of thermal fluids are numerically analyzed by using the finite-volume method on 3-D meshed physical models and then compared with those using a constant boundary temperature. The results show that voltage and current of the TE module increase gradually from a beginning moment to a steady flow and reach a stable value. The stable values increase with inlet temperature of the hot fluid when the inlet temperature of cold fluid is fixed. However, the time to get to the stable values is almost consistent for all the temperature differences. Moreover, the trend of TE performance using a fluid flow boundary is similar to that of using a constant boundary temperature. Furthermore, 3-D contours of fluid pressure, temperature, enthalpy, electromotive force, current density and heat flux are exhibited in order to clarify the influence of counter-flows of ideal fluids on TE generation. The current density and heat flux homogeneously distribute on an entire TE module, thus indicating that the counter-flows of thermal fluids have high potential to bring about fine performance for TE modules

Thermoelectric performance using counter-flowing thermal fluids

Counter-flowing thermal fluids are conducive to generate a homogeneous temperature difference on thermoelectric (TE) generator. This study allowed the hot and cold fluids of having constant inlet temperature to flow in the opposite, and examined TE performance of module at different flow rates. The results show that TE performance gradually increases with flow rate in the initial stage of fluid flow, and reaches a transient peak value after the module surfaces are completely covered by thermal fluids, and then tends to be stable. High flow rate leads to larger performance and reduces the time of achieving them. Effect of flow rate on stable performance is slightly more than that of inlet temperature of thermal fluids, which makes regulating the flow rate to be a feasible way to harvest more heat for TE conversion. Module features present a specific trend and provide the supports for the benefit of counter-flowing thermal fluids. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved