A NOVEL SYNTHESIS METHOD OF LIPOPHILIC EGCG PALMITATE AND EVALUATION FOR ITS ALPHA AMYLASE AND ALPHA GLUCOSIDASE INHIBTORY POTETIAL | Author : Weidong Yan | Abstract | Full Text | Abstract :This work describes a green and novel approach to synthesize a lipophilic EGCG palmitate by chemical acylation of EGCG with palmitoyl chloride, and thus the significant elevated stability and bioavailability of EGCG are achieved. Various parameters affecting the acylation reaction process, such as the base, solvent, as well as the mole ratio of palmitoyl chloride have been studied, in order to optimize the acylation procedure. The compound 1 in the reaction mixture was separated by silica column chromatography. The compound 1 was confirmed by HPLC-MS and NMR and was identified as the EGCG palmitate (PEGCG). The stability of the EGCG palmitates and EGCG in different conditions were studies. Compared with EGCG, PEGCG showed better inhibition on the activities of a-amylase and a-glucosidase, with IC50 values of 1.64 and 0.22 µM, respectively. These observations open a novel and effective synthetic pathway for derivation of EGCG and suggest that the lipophilic PEGCG may act as an antidiabetic agent.
Keywords: EGCG; Acylation; a-Glucosidase inhibition; a-Amylase inhibition; Antidiabetic activities |
| Drying characteristics and solar convective drying kinetics of China Hami melon slice | Author : Hai Wang | Abstract | Full Text | Abstract :This experimental study aims to investigate the influence of solar drying parameters on water loss of fresh Hami melon flakes. This article presented the experiment results of drying kinetics .In this study, drying kinetics was conducted on a solar convective dryer with heat pump at four air temperatures (i.e., 40 °C, 50 °C, 60 °C, and 70 °C), flow rates (i.e., 1, 2, 3, and 4 m/s), and sample thickness (i.e., 2, 5, 8, and 11 mm). The characteristic drying curve of Hami melon has been determined by experimental results. Eight models were simulated, and the Midilli–Kucuk model had highest fitting degree in thin layer drying models when all drying data was simulated. Within the scope covered, Fick’s second law of diffusion was often used to compute an effective water diffusivity, which raised from 8.66×10-11 m2/s to 3.12×10-9 m2/s with drying temperatures, airflow rates, and thickness. The activation energy is 11.71 kJ/mol, it indicates the effect of temperature on diffusion coefficient.
Keywords: Hami melon; Solar drying; Kinetics; Characteristic drying curve; Drying models |
| Large genome deletions reveal gene effects on ethanol tolerance in Saccharomyces cerevisiae | Author : Mingqiang Qiao | Abstract | Full Text | Abstract :The yeast Saccharomyces cerevisiae, which is a model system for biological research, has been widely used as an industrial host. Using the mazF-mediated deletion system, we made large deletions, including both terminal and internal regions of the chromosome. We obtained 12 deletion strains with different sizes of the deleted genome region(s), varying from 20 kb to 80 kb. Each deletion removed a cluster of non-essential genes, as deduced by an online prediction program. Phenotype analysis of the mutants with large deletions showed that genome regions YOR124C/YOR134W and YOL020W/YOL011W appeared to be related to ethanol tolerance and high salinity sensitivity, respectively. The loss of CAT5, ADE2, or RGA1 reduced the ethanol tolerance of yeast. Dispensable genes or interactions among non-essential genes were involved in the functional effects of genome deletions.
Key words: ethanol tolerance; genome deletions; non-essential genes; oxygen response; Saccharomyces cerevisiae |
| The quality assessment of frozen shrimp (Metapenaeus ensis): protein changes, texture and total volatile basic nitrogen | Author : Shan Xiao | Abstract | Full Text | Abstract :Proteins of shrimp muscle suffered chemical and physical changes during frozen storage which may result in quality deterioration. There are lots of parameters widely used to assess the degree of protein changes. While, not much information was available on using different parameters to investigate changes in proteins of frozen shrimp. The present study was conducted to evaluate the changes in proteins using different parameters, including myofibrillar solubility, myofibrillar size distribution and myofibrillar UV absorption spectrum. Meanwhile, in order to make clear the direct effects of these protein changes on frozen shrimp quality, the variation in total volatile basic nitrogen (TVB-N), texture and microstructure were determined as well. The results of this research may help to better understand the mechanism of frozen shrimp quality deterioration. The results showed that the protein had been changed during shrimp frozen storage which could result from protein freeze denaturation, protein oxidation, protein degradation and other biochemical actions. All the three parameters could well characterize the changes in protein during shrimp frozen storage. It was shown that the TVB-N levels increased, and the texture and microstructure went worse over shrimp frozen storage. These variations could be the results of protein changes.
Keywords Shrimp, Frozen, Quality, Protein |
| The Anti-Hyperplasia of Mammary Gland Effect of Chinese Traditional Medicine compound RPXT in Rats | Author : Dongshun Zhou | Abstract | Full Text | Abstract :Rupixiao Tablets (RPXT) is a Chinese Traditional Medicine compound and comprises of 15 Chinese medicines, but the effect of anti-mammary gland hyperplasia, toxicity and mechanism are not clear. We investigated the protective effect of RPXT on hyperplasia of mammary gland (HMG) induced by estrogen and progestogen in SD rats. The rats were randomly divided into three groups (n = 10), including normal control group, HMG model group and RPXT treatment group. The toxicity study of RPXT on HMG rats was performed at 500 mg/kg/day by i.g. for 35 consecutive days. Changes of nipple height and diameter, serum sex hormones levels and organ indexes, pathologic changes of mammary gland, heart, liver, spleen, kidney and lung, hematological and biochemical analysis were measured or observed to evaluate the anti-HMG effect and toxicology of RPXT. The expression of AP-2a, P53 and caspase-3 in mammary gland of rats were analyzed by western blot. The results indicated that RPXT could remarkably decrease nipple height and diameter, uterus index and E2 concentration of HMG rat serum, and no toxicity at dose of 500 mg/kg/day. AP-2a, P53 and caspase-3 expression in mammary gland was significantly decreased in mammary gland of RPXT -treated HMG rats. The whole results indicated that RPXT has protective and therapeutic effects on HMG rats, and is a promising Chinese Traditional Medicine for human mammary cancer prevention which is related to caspase-3, AP-2a and P53 expression.
Key words: Chinese Traditional Medicine compound; anti-hyperplasia of mammary gland; toxicity; RPXT |
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