Emulsifying Properties of Polysaccharide Conjugates Prepared from Chin-Brick Tea.

Chin-brick tea polysaccharide conjugates (TPC-C) were prepared to study their emulsion capabilities. Interfacial tension and the effects of some factors, such as storage time, metal ion concentrations (Na+, Ca2+), pH (2.0-8.0), and heat treatment (70-100 °C) on the emulsions stabilized by TPC-C were studied. The interfacial tension of TPC-C (10.88 mN/m) was lower than that of gum arabic (15.18 mN/m) at a concentration of 0.08%. As the TPC-C concentration increased from 0.1 to 3.0 wt %, the mean particle diameter (MPD) (d32) of emulsions stabilized by TPC-C decreased from 1.88 to 0.16 µm. Furthermore, at a concentration of 0.5 wt % or higher, the MPD (d32) of emulsions stabilized by TPC-C at 25 and 60 °C for 10 days was between 0.20 and 0.50 µm. In the tested pH conditions from 2.0 to 8.0, the MPD (d32) of emulsions stabilized by 2.0 wt % TPC-C was less than 0.20 µm. At Na+ concentration conditions between 0.10 and 0.50 mol/L, the MPD (d32) of emulsions was between 0.19 and 0.20 µm, and the zeta potential values varied from -34.10 to -32.60 mV. However, with an increasing Ca2+ concentration from 0.01 to 0.05 mol/L, the MPD (d32) of emulsions was between 0.20 and 21.65 µm, and the zeta potential raised sharply from -34.10 to -28.46 mV. The emulsions stabilized by TPC-C have a decent storage stability after a high-temperature heat treatment. Overall, tea polysaccharide conjugates strongly stabilized the emulsions, which support their new application as natural emulsifiers.

Some Physical Properties of Protein Moiety of Alkali-Extracted Tea Polysaccharide Conjugates Were Shielded by Its Polysaccharide.

Polysaccharide conjugates were alkali-extracted from green tea (TPC-A). Although it contained 11.80% covalently binding proteins, TPC-A could not bind to the Coomassie Brilliant Blue dyes G250 and R250. TPC-A had no expected characteristic absorption peak of protein in the UV-vis spectrum scanning in the range of 200-700 nm. The UV-vis wavelength of 280 nm was not suitable to detect the presence of the protein portion of TPC-A. The zeta potential of TPC-A merely presented the negative charge properties of polysaccharides instead of the acid-base property of its protein section across the entire pH range. Furthermore, TPC-A was more stable when the pH of solution exceeded 4.0. In addition, no precipitation or haze was generated in the TPC-A/(-)-epigallocatechin gallate (EGCG) mixtures during 12 h storage. TPC-A has emulsifying activity, which indicated that its protein moiety formed hydrophobic groups. Thus, it was proposed that some physical properties of TPC-A protein were shielded by its olysaccharide, since the protein moiety was wrapped by its polysaccharide chains.

Preventive Effects of Catechins on Cardiovascular Disease.

Catechins are polyphenolic phytochemicals with many important physiological activities that play a multifaceted health care function in the human body, especially in the prevention of cardiovascular disease. In this paper, various experimental and clinical studies have revealed the role of catechins in the prevention and treatment of cardiovascular disorders, and we review the preventive effects of catechins on cardiovascular disease from the following aspects: Regulating lipid metabolism, regulating blood lipid metabolism, vascular endothelial protection, and reducing blood pressure.

Effect of vascular network and nanoparticles on heat transfer and intracellular ice formation in tumor tissues during cryosurgery.

BACKGROUND: Cryosurgery is a physical therapy of tumor treatment which is welcome in clinics for its minimally invasive advantage. However, the high recurrence rate makes the conventional cryosurgery unsatisfactory, which needs adjuvant treatment such as introduction of nanoparticles. OBJECTIVE: This study is to examine the effects of vascular network and MgO nanoparticles on heat transfer and intracellular ice formation in tumor tissues during cryosurgery. METHOD: We developed a multi-scale model to study the efficiency of cryosurgery, including the macro-level (mass tumor tissue) heat transfer and the micro-level (tumor cells) probability of intracellular ice formation (PIF). The model is used to examine the effects of fractal vascular network (VN) and nanoparticles with different concentration on heat transfer and PIF during cryosurgery in the breast cancer tissue (MCF-7 cells). The nucleation rate kinetic parameter and the thermodynamic parameter of MCF-7 cells are determined by nonlinear curve-fitting the published experimental data, and then the probability of intracellular ice formation of the picked points in the tumor tissue are determined using the classic model for intracellular ice nucleation with the simulated thermal profiles at those points during cryosurgery. RESULTS AND CONCLUSION: The introduction of nanoparticles have significantly enhanced the heat transfer in the mass tumor tissue and increased the PIF of tumor cells, indicating the nanocryosurgery is more efficient than conventional cryosurgery.

A new decalin derivative from red yeast rice.

A new decalin derivative, monascusic acid A (1), together with a new natural product (2), was isolated from the ethanol extract of red yeast rice. Their structures were elucidated by spectroscopic methods.