NMR Analysis of Lipid Oxidation in Flaxseed Oil-in-Water Emulsions.

The formation of linolenic (Ln) and linoleic (L) acyl oxidation products during storage of flaxseed oil (FO)-in-water emulsions was monitored using proton nuclear magnetic resonance (1H NMR) spectroscopy, as well as chemical analytical methods and gas chromatography. Emulsions containing 10% FO and 1% Tween 60 were prepared by homogenization and then stored at 37 °C in the dark for 21 days under accelerated oxidation conditions (500 µmol ferrous sulfate). The induction time of the emulsions, after which rapid lipid oxidation was first observed, was 5-7 days, as shown by increases in peroxide values and hydroperoxide concentrations determined by NMR spectroscopy. Analysis of the hexanal and propanal concentrations during storage by HS-SPME-GC indicated that the oxidation of Ln and L acyls in the emulsions occurred simultaneously. The oxidation products originating from the Ln and L acyls were monitored using 1H NMR spectroscopy throughout the oxidation process. These results also showed that the Ln and L acyls oxidized simultaneously, and isomers of hydroperoxy-cyclic hydroperoxides (HCPs), Z,E-conjugated dienic hydroperoxides (ZECDHPs), and E,E-conjugated dienic hydroperoxides (EECDHPs) were the major primary oxidation products. Aldehydes were observed after 7 days, which was taken to be the start of the propagation stage, with the formation of a significant amount of oxygenated α, ß-unsaturated aldehydes (OαßUAs). Based on the concentrations of hydroperoxides originating from the Ln and L acyls, our results suggested that the loss rate of L acyls was parallel to that of Ln acyls. This result was consistent with Ln acyls adopting a tighter packing at the oil-water interface in the emulsions than L acyls. This hypothesis was supported by the NMR relaxation time data. A good correlation between the isomer concentrations of ZECDHPs and HCPs in Ln acyls and between ZECDHPs and EECDHPs in L acyls was shown, with the mole ratios between them being 1.2 and 1.1, respectively. Droplet size and microstructure analyses showed that droplet aggregation occurred from 11 days onwards, which was attributed to polar oxidation products located at the oil droplet surfaces promoting coalescence. Zeta-potential measurements indicated that the droplets became more negative during storage, which was attributed to the accumulation of anionic reaction products at the droplet surfaces.

Research progress of the CXCR4 mechanism in Alzheimer's disease.

Alzheimer's disease (AD) is a degenerative brain disease with complex clinical manifestations and pathogeneses such as abnormal deposition of beta-amyloid protein and inflammation caused by the excessive activation of microglia. CXC motif chemokine receptor type 4 (CXCR4) is a type of G protein-coupled receptor that binds to CXC motif ligand 12 (CXCL12) to activate downstream signaling pathways, such as the Janus kinase/signal transducer and activator of transcription and the renin-angiotensin system (Ras)/RAF proto-oncogene serine (Raf)/mitogen-activated protein kinase/extracellular-regulated protein kinase; most of these signaling pathways are involved in inflammatory responses. CXCR4 is highly expressed in the microglia and astrocytes; this might be one of the important causes of inflammation caused by microglia and astrocytes. In this review, we summarize the mechanism and therapeutics of AD, the structures of CXCR4 and the CXCL12 ligand, and the mechanisms of CXCR4/CXCL12 that are involved in the occurrence and development of AD. The possible treatment of AD through microglia and astrocytes is also discussed, with the aim of providing a new method for the treatment of AD.

Four new compounds from the roots of Euphorbia ebracteolata and their inhibitory effect on LPS-induced NO production.

Three new diterpenoids, ebractenoids O~Q (1-3), and a new phenolic glucoside, γ-pyrone-3-O-ß-d-(6-galloyl)-glucopyranoside (4), together with 6 known compounds, were isolated from the 95% ethanol extract of the roots of Euphorbia ebracteolata, and their structures were elucidated on the basis of spectroscopic data. The absolute configurations of 1-3 were determined by electronic circular dichroism (ECD) calculations. The inhibitory effects of all the isolates with exception of compounds 8 and 10 on the NO production in lipopolysaccharide (LPS)-induced macrophages were evaluated. All of them exhibited significant inhibitory activity.