Novel acylflavones from Sideritis syriaca ssp. syriaca

In the framework of the detailed phytochemical analysis of the aerial parts of Sideritis syriaca, two novel acylflavones were isolated together with three acetylated flavone glycosides and acylated flavone glycosides. The novel acylflavones were identified as isoscutellarein 7-trans-p-coumarate and apigenin 7-,4′-bis(trans-p-coumarate). Their structures were elucidated by means of UV, 1D and 2D NMR, LC–DAD–MS and confirmed by HR-MS spectroscopy.     

Fractionation of soybean phospholipids by high-performance liquid chromatography with an evaporative light-scattering detector

Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from 23 soybean lines with a wide range of fatty acid compositions were resolved into seven fractions by high-performance liquid chromatography (HPLC). Fraction identities were assigned from fatty acid compositions determined by gas chromatography (GC). A mass detector, i.e., an evaporative light-scattering detector, was used for HPLC quantification. The detector response was a power function of PC and PE concentrations. Various correction methods were applied to the detector response to obtain the best agreement between phospholipid (PL) fatty acid compositions determined by GC and that calculated from the corrected HPLC fraction percentages. The corrected HPLC fraction composition also was compared with that calculated from stereospecific distribution data using a 1-random-2-random hypothesis. Correlation between PL-fatty acid and HPLC-fraction percentages showed that genetic modification of soybean oil composition caused changes in PL species, which alter physical properties and may alter the physiological functions of PL in biomembranes.     

A simple and cost-effective gram-scale chromatographic method for the purification of soybean phospholipids

A method was developed for the preparative fractionation of soybean lecithin to enable the study of the functional properties of pure soybean phospholipids. Hereby, a coarse and irregularly shaped silica gel was used as the stationary phase, whereas the mobile phase consisted of three mixtures of hexane, 2-propanol, and water with increasing polarity. These solvents were included in a step gradient, which was formed by an isocratic pump connected to a solvent switcher. With this system, two grams of soybean lecithin were fractionated. The purity was evaluated by analytical high-performance liquid chromatography, and the recovery was estimated from concentration determinations by flow injection analysis. From these results, it was concluded that 60 to 75% of the three major soybean phospholipids could be recovered with a purity of at least 93%. Only 1.5 L of solvents were needed for both the column equilibration and the elution of all soybean phospholipids. Senior research associate of the Belgian National Fund for Scientific Research (N.F.W.O.).     

Structure–activity relationships of acetylated flavone glycosides from Galeopsis ladanum L. (Lamiaceae)

Antioxidant activity, neuroprotective effect and acetylcholinesterase inhibitor activity were studied in acetylated flavones from Galeopsis ladanum L. (Lamiaceae), previously isolated and identified by UV-spectra, UPLC–MS/MS and ¹H-NMR spectroscopy. Structure–activity relationships of flavonoids have been determined in many antioxidant assays, generally focused on hydroxyl groups. In this study we have detected new interesting structure–activity relationships for the isolated flavonoids due to the acetylation of sugar moiety of these flavonoids. Methylation at 4′-OH and monoacetylation is beneficial to inhibiting AChE and shows a neouroprotective effect.     

Symposium review: Milk fat globule size: Practical implications and metabolic regulation

Milk fat globule (MFG) size ranges over 3 orders of magnitude, from less than 200 nm to over 15 µm. The significance of MFG size derives from its tight association with its lipidome and proteome. More specifically, small MFG have relatively higher content of membrane compared with large globules, and this membrane exerts diverse positive health effects, as reported in human and animal studies. In addition, MFG size has industrial significance, as it affects the physicochemical and sensory characteristics of dairy products. Studies on the size regulation of MFG are scarce, mainly because various confounders indirectly affect MFG size. Because MFG size is determined before and during its secretion from mammary epithelial cells, studies on the size regulation of its precursors, the intracellular lipid droplets (LD), have been used as a proxy for understanding the mechanisms controlling MFG size. In this review, we provide evidence for 2 distinct mechanisms regulating LD size in mammary epithelial cells: co-regulation of fat content and triglyceride-synthesis capacity of the cells, and fusion between LD. The latter is controlled by the membrane's polar lipid composition and involves mitochondrial enzymes. Accordingly, this review also discusses MFG size regulation in the in vivo metabolic context, as MFG morphometric features are often modulated under conditions that involve animals' altered energy status.     

菜籽油脚中脑磷脂的提取与纯化工艺研究

以菜籽油脚为原料,采用溶剂分提法与柱色谱分离法相结合的工艺制备高纯度脑磷脂(PE).通过正交试验得出最佳的溶剂分提工艺参数为:分提时间20 min,粉末磷脂与95%乙醇溶剂比1:7,分提次数3次,分提温度40℃.在此条件下所得产物中PE含量为46.3%.采用硅胶为固定相的柱色谱分离技术对溶剂分提产物进行进一步纯化,试验结果表明:控制洗脱流速为3 mL/min,进样量为1.5 g(100 g硅胶),氯仿-甲醇(体积比2:1)为洗脱剂的条件下分离效果较好,所得PE产品的纯度为94.5%,回收率为85.1%.