Lipidomics and metabolomics reveal the molecular mechanisms underlying the effect of thermal treatment on composition and oxidative stability of walnut oil.

Roasting walnut kernel significantly improves the oxidative stability and sensory properties of its oil. However, the effect of roasting temperatures on the molecular change of main components and micronutrients in walnut oil is still unclear. Herein, lipidomics and metabolomics were integrated to comprehensively profile the walnut oil obtained at different roasting temperatures (30 °C, 120 °C, 140 °C, 160 °C, and 180 °C). Lipidomics showed that the content of glycerolipids, sphingolipids, and glycerophospholipids decreased with roasting temperatures, while the oxidized fatty acids and triglycerides increased. Ratios of linoleic acid and linolenic acid varied with roasting temperatures and were most close to 4-6:1 at 140 °C, 160 °C, and 180 °C. Major classes of micronutrients showed a tendency to increase at the roasting temperature of 120 °C and 140 °C, then decrease at 160 °C and 180 °C. Liposoluble amino acids identified for the first time in walnut oil varied with roasting temperatures. Correlation analysis demonstrated that the higher contents of liposoluble amino acids and phenolics are positively associated with enhanced oxidative stability of walnut oil obtained at 140 °C. Furthermore, glutamine and 5-oxo-D-proline were expected to be potential biomarkers to differentiate the fresh and roasted walnut oil. The study is expected to provide new insight into the change mechanism of both major lipids and micronutrients in walnut oil during the roasting process.

Liquid Chromatography Tandem Mass Spectrometry Based Label-Free Quantification Method for Assessment of Allergen-Induced Anaphylactoid Reactions.

Mast cells are essential in mediating inflammatory processes. When activated, mast cells can rapidly release characteristic granules and various mediators into the interstitium. Tryptase (TPS) and ß-hexosaminidase (HEXB) are typical protease mediators stored in granules and released upon activation. They have been recognized as important biomarkers of anaphylaxis, and the released level is associated with the severity of allergic reactions. In this study, a sensitive, accurate, and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneously quantifying the two biomarkers was developed and validated in LAD2 cell culture supernatant, and P14R was used as internal standard. Good linearity was observed in the range of 50-2500 ng/mL for TPS and 10-2000 ng/mL for HEXB both with R2 > 0.99. The matrix effect and recovery were both within acceptable limits. We quantified TPS and HEXB released from Laboratory of Allergic Disease 2 (LAD2) mast cells treated with several potential allergens, and the results demonstrate that the method can be used to investigate TPS and HEXB levels in LAD2 mast cell model during allergy research. We anticipate our approach to be a robust and sensitive assessment method for more biomarkers with similar kinetics characteristics and to be a major tool of allergic drug assessment or antiallergic drug development in research.

Occurrence and indicators of pharmaceuticals in Chinese streams: A nationwide study.

Pharmaceutically active compounds (PhACs) are excreted by humans and animals and released into the aquatic environment through wastewater, which can have potential negative impacts on ecological systems. To conduct a nationwide investigation of the occurrence of PhACs in water resources in China, an analytical procedure based on solid-phase extraction (SPE) and LC-MS/MS was used to measure 45 PhACs in surface water samples from a network of 29 rivers across 31 provinces in China in 2014 and 2015. PhACs were prevalent in all sampled streams. The concentrations of commonly detected PhACs were comparable to those detected in other countries. High total concentrations (mean > 1 µg L-1) of all tested PhACs were primarily detected in areas under extreme water stress, specifically northern and eastern coastal areas. Source apportionment based on the profiles of the target compounds found that 54% of the PhACs in China originated from freshly discharged untreated sewage. Metformin (MET) and its biodegradation product, guanylurea (GUL), were used as a pair of indicators to predict PhAC contamination levels and differentiate between biotreated and unbiotreated wastewater. High MET/GUL can be used to indicate untreated wastewater, whereas low MET/GUL values are a strong indicator of treated wastewater. Furthermore, wastewater biotreatment ratios were calculated. We estimated that the biotreatment ratios of most of the provinces in China were less than 50%. We conclude that more attention should be paid to untreated sewage water, especially water in rural areas rather than the existing concentration on urban sewage treatment-oriented management.

Quantitation of lanosterol in the vitreous humor of rabbits after ocular administration of lanosterol/thermogel formulation by ultra high performance liquid chromatography-tandem mass spectrometry with the electrospray ionization mode.

Cataracts are the most common cause of blindness worldwide affecting tens of millions of people. Here, we report a simple, rapid, sensitive and specific method by ultra performance liquid chromatography-tandem mass spectrometry with the electrospray ionization mode (UPLC-ESI-MS/MS) for quantitation of lanosterol, a possible effective drug for cataracts, in the vitreous humor of rabbits after ocular administration. The injected lanosterol was prepared by dispersing lanosterol molecules into the poly-(dl-lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly-(dl-lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) thermogel solution. The analyte and internal standard (IS, panaxadiol) were extracted by the simple protein precipitation with methanol. The chromatographic separation used an Agilent RRHD SB-C18 column with a methanol mobile phase containing 50mM of ammonium acetate aqueous solution (with 0.1% formic acid) (95:5, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring (MRM) with a mass spectrometer. The mass transitions m/z 443.5→235 and m/z 461→127 were used to measure the analyte and IS, respectively. The assay exhibited a linear dynamic range of 1-1250ngmL-1 for lanosterol in vitreous samples. The lower limit of quantitation (LLOQ) was 1ngmL-1 with a relative standard deviation (RSD) of less than 15%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 5min per sample offered a throughput of more than 200 samples per day. This validated method was used to analyze vitreous samples of New Zealand white rabbits for pharmacokinetic studies. The results provided useful information on pharmacological action mechanism of lanosterol and were meaningful for cataract treatment among the elderly population.