食品功能性成分降血脂作用机理研究进展

高脂饮食的摄入打破了体内脂质代谢平衡,是目前高脂血症患者数量急剧增加的原因之一。具有降血脂功效的食品很多,其功能成分主要为膳食纤维、多糖类、多酚类、生物碱类、皂苷等。本文综述了食物中常见的具有降血脂作用成分的功效及其作用机制的最新研究进展,为降血脂研究及功能食品的开发提供参考。     

Human synthetic sebum formulation and stability under conditions of use and storage

The human skin surface and hair are generally coated with a thin film of liquid phase sebaceous lipids. This surface lipid film contributes to the cosmetic properties of the skin. Synthetic sebum has been used for studies on properties of skin and hair. However, there has been no standardized formulation of synthetic sebum and many of the synthetic sebum formulations that have been used do not closely resemble actual sebum. In this study, a formulation for a standardized and inexpensive synthetic sebum is proposed, and the chemical stability of this lipid mixture is demonstrated under conditions of use and storage. The proposed synthetic sebum consists of 17% fatty acid, 44.7% triglyceride, 25% wax monoester (jojoba oil) and 12.4% squalene. This lipid mixture takes up approximately 6% of its weight in water when equilibrated in an atmosphere saturated with water vapour. It is stable on exposure to the atmosphere at 32°C for at least 48 h, and it is also stable on storage at 4 or −20°C, either dry or in chloroform : methanol solution for at least 6 months. This synthetic sebum could be useful in studies on cosmetic properties of the skin surface or hair, on penetration of chemicals into the skin or in development of standardized tests of laundry detergent performance.     

干腌火腿脂类的研究现状

脂类物质在火腿成熟过程中有非常重要的作用,是干腌火腿主要的风味前体物质。火腿中的脂类物质主要是甘油酯和磷脂、磷脂,对风味物质形成的贡献最突出。腌制过程中,脂类物质主要发生了水解、氧化。本文综合论述了脂类物质在火腿加工过程中所发生的变化及变化机制,并讨论了这些变化在火腿风味形成中的作用。     

Changes in the oxidative state of extra virgin olive oil used in baked Italian focaccia topped with different ingredients

Four different types of “focaccia” (Italian flat bread) prepared with the same dough and the same extra virgin olive oil but with different seasonings, were analyzed. Lipids were extracted from each sample using the Folch method. The indices commonly used to assess oil quality, the amounts of trans fatty acids and compounds of triglyceride polymerization, oxidation and hydrolysis, were determined in all the samples to better assess the degree of oxidation and hydrolysis of the oils. The findings showed that, once baked, the oil sampled from the different types of focaccias could not be included in the virgin category. The level of oxidation of the baked samples was greater than that in the uncooked oil. However the results obtained showed that the level of degradation of the extracted oils was lower than that found in edible refined oils and it seemed to be influenced by the topping used to flavour the focaccias.     

Lipase catalyzed formation of fatty amides

Certain lipase preparations were found to facilitate the preparation of fatty amides at 20°C in hexane. Lipase preparations investigated were from the fungiCandida rugosa, Rhizomucor miehei and porcine pancreas. Reactants were various primary alkylamines and fatty acid methyl esters or triglycerides. Moderate yields of fatty amides were obtained using aR. miehei lipase preparation which is immobilized on a solid support as catalyst, although all three lipase preparations showed some catalytic activity under these conditions and, in addition, showed different kinds of selectivity for fatty acid and alkylamine chain lengths. No reaction was observed in similar experiments using one fatty acid as the substrate or one secondary amine.     

中碳链甘油三酯及其应用

综述了中碳链甘油三酯的理化性质、体内代谢特色、中碳链甘油三酯的合成方法以及中碳链甘油三酯的应用及其安全性，对于开发研究中碳链甘油三酯具有参考价值。     

Electrospray ionization MS of high M.W. TAG oligomers

Reported are the on-line LC/electrospray ionization MS of large, high M.W. oligomers formed from heated triolein, a TAG used as a model for dietary oils. Triolein, the major component of olive oil, canola oil, and other dietary oils, was heated at frying temperature, and the TAG oxidation products were separated using RP-HPLC coupled to an ion trap mass spectrometer via an electrospray ionization interface. Ammonium formate was added as a sheath liquid to promote ammonium adduct formation. Masses corresponding to ammonium adducts of intact carbon-linked dimers (m/z 1783–1787), trimers (m/z 2666–2672), and tetramers (m/z 3547–3557) of triolein, with and without additional sites of unsaturation, were observed. Also, dimers, trimers, and tetramers containing one, two, or three additional oxygens, also with and without additional sites of unsaturation, are reported. Based on the formation of some types of triolein dimers, we believe that tristearin might also form dimers, even though it has no readily oxidizable sites of unsaturation. Oxidized tristearin monomers, tristearin dimers, chainaddition products, and chain-shortened products are observed.     

TG68, a Novel Thyroid Hormone Receptor-β Agonist for the Treatment of NAFLD

Activation of thyroid hormone receptor β (THRβ) has shown beneficial effects on metabolic alterations, including non-alcoholic fatty liver disease (NAFLD). Here, we investigated the effect of TG68, a novel THRβ agonist, on fatty liver accumulation and liver injury in mice fed a high-fat diet (HFD). C57BL/6 mice fed HFD for 17 or 18 weeks, a time when all mice developed massive steatohepatitis, were then given TG68 at a dose of 9.35 or 2.8 mg/kg for 2 or 3 weeks, respectively. As a reference compound, the same treatment was adopted using equimolar doses of MGL-3196, a selective THRβ agonist currently in clinical phase III. The results showed that treatment with TG68 led to a reduction in liver weight, hepatic steatosis, serum transaminases, and circulating triglycerides. qRT-PCR analyses demonstrated activation of THRβ, as confirmed by increased mRNA levels of Deiodinase-1 and Malic enzyme-1, and changes in lipid metabolism, as revealed by increased expression of Acyl-CoA Oxidase-1 and Carnitine palmitoyltransferase-1. The present results showed that this novel THRβ agonist exerts an anti-steatogenic effect coupled with amelioration of liver injury in the absence of extra-hepatic side effects, suggesting that TG68 may represent a useful tool for the treatment of NAFLD.     

Cell-cell communication between mouse mammary epithelial cells and 3T3-L1 preadipocytes: effect on triglyceride accumulation and cell proliferation.

Interaction between parenchyma and stroma is essential for organogenesis, morphogenesis, and differentiation. Mammary gland has being the chosen model for developmental biologist because the most striking changes in morphology and function take place after birth. We have demonstrated a regulation of triglyceride accumulation by protein factors synthesized by normal mouse mammary gland epithelial cells (NMMG), acting on a cell line, 3T3-L1, long used as a model for adipogenesis. In this paper, we demonstrate that this inhibitory effect seems to be shared by other cells of epithelial origin but not by other cell types. We found a regulation of cell proliferation when NMMG cells are cultured in the presence of conditioned media from Swiss 3T3 or 3T3-L1 cells. We found a possible point of regulation for the mammary factor on a key enzyme of the lipid metabolic pathway, the glycerol-3-phosphate dehydrogenase. The inhibitory factor seems to have an effect on this enzyme's activity and reduces it. The results presented herein contribute to the understanding of cell-cell communication in a model of a normal mammary gland.