Serum metabolomics analyses reveal biomarkers of osteoporosis and the mechanism of Quanduzhong capsules.

With the aging of the population, the prevalence of osteoporosis (OP) is rising rapidly, making it an important public health concern. Early screening and effective treatment of OP are the primary challenges facing the management of OP today. Quanduzhong capsule (QDZ) is a single preparation composed of Eucommia ulmoides Oliv., which is included in the Pharmacopoeia of the People's Republic of China. It is used to treat OP in clinical practice, but its mechanisms are unclear. This study involved 30 patients with OP, 30 healthy controls (HC), and 28 OP patients treated with QDZ to identify potential biomarkers for the early diagnosis of OP and to investigate the potential mechanism of QDZ in treating OP. The serum samples were analyzed using targeted amino acid metabolomics. Significant differences in amino acid metabolism were identified between the OP cohort and the HC group, as well as between OP patients before and after QDZ treatment. Compared with HC, the serum levels of 14 amino acids in OP patients changed significantly. Kynurenine, arginine, citrulline, methionine, and their combinations are expected to be potential biomarkers for OP diagnosis. Notably, QDZ reversed the changes in levels of 10 amino acids in the serum of OP patients and significantly impacted numerous metabolic pathways during the treatment of OP. This study focuses on screening potential biomarkers for the early detection of OP, which offers a new insight into the mechanism study of QDZ in treating OP.

[Simultaneous determination of eight additives in polyethylene food contact materials by ultrahigh-performance liquid chromatography].

Measurement of additive residues in food contact materials is important for safety monitoring at the initial stage. Most of the current studies focus on the determination of the migration amounts of chemical hazards from food contact materials into food simulants. Studies on chemical hazard residues in food contact materials are limited to monomers, oligomers, heavy metals, phthalic acid esters, and biphenols, which are known environmental pollutants. Only a few studies have investigated analysis methods for additive residues in food contact materials. In this study, the main factors (monitoring wavelength, chromatographic column, mobile phase, extraction solvent, etc.) that affect the accuracy and sensitivity of eight compounds, including three antioxidants, three light stabilizers, and two plasticizers, were investigated during sample preparation and instrument analysis. A method based on ultrahigh-performance liquid chromatography (UPLC) was developed for the simultaneous determination of these eight additives in polyethylene (PE). The PE food contact material sample was ground to homogenize the particle sizes under freeze-grinding. After comparing the extraction efficiencies of methylbenzene, chloroform, acetone, and acetonitrile, 2.0 g of the sample was extracted with methylbenzene at 80 ℃ and 10.34-11.72 MPa (1500-1700 psi) by accelerated solvent extraction (ASE) for 10 min once. The exaction solvent (10 mL) was transferred and concentrated to near dryness under a gentle stream of nitrogen gas and then re-dissolved in 10 mL of the initial mobile phase (70% (v/v) methanol in water). Finally, the eight compounds were analyzed by UPLC. After optimization of the analytical column and mobile phases, the eight analytes were separated on an ACQUITY UPLC BEH C8 chromatographic column (100 mm×2.1 mm, 1.7 µm) by gradient elution using water and acetonitrile as the mobile phases. The column oven temperature, flow rate of the mobile phase, and injection volume were 30 ℃, 0.3 mL/min, and 5 µL, respectively. The analytes were detected by a diode assay detector (DAD) in the scanning range of 210 nm to 400 nm. The monitoring wavelength was set at 230 nm, 250 nm, 280 nm, and 330 nm. External standard calibration curves were used for quantification. Under the optimized conditions, the calibration curves for the eight compounds showed good linearity in the range of 0.2 µg/mL to 10 µg/mL, and the correlation coefficients were >0.999. The recoveries in spiked blank polyethylene samples at the level of 0.05% were in the range of 83.8% to 103.4%, with relative standard deviations (RSDs) ranging from 0.14% to 7.86%. To validate the method, PE reference materials containing these eight compounds were manufactured at the content level of 0.2% to 0.9%. The recoveries using the prepared reference materials ranged from 63.5% to 118.5%, and the RSDs were in the range of 4.61% to 15.6%. The limits of detection (LODs, S/N=3) of all the eight compounds were 0.005% and the limits of quantification (LOQs, S/N=10) were 0.02%, in compliance with the current legislation. To assess the feasibility and potential of the proposed approach for routine analyses of these eight compounds, the developed method was applied to the analysis of these compounds in ten PE food packages and PE gloves. In six samples, tris(2,4-di-tert-butylphenyl)phosphite (Irganox 168) was detected at a level of 0.02%-0.07%, which was lower than the maximum level of this compound in PE food contact material products regulated in GB 9685-2016 at 0.2%. The method is compliant with the current legislation, and it can be used for the monitoring and supervision of these eight additives in PE food contact materials.

Pharmacokinetics and Tissue Distribution of Alnustone in Rats after Intravenous Administration by Liquid Chromatography-Mass Spectrometry.

Alnustone, a nonphenolic diarylheptanoid, first isolated from Alnus pendula (Betulaceae), has recently received a great deal of attention due to its various beneficial pharmacological effects. However, its pharmacokinetic profile in vivo remains unclear. The purpose of this study is to establish a fast and sensitive quantification method of alnustone using liquid chromatography tandem mass spectrometry (LC-MS/MS) and evaluate the pharmacokinetic and tissue distribution profiles of alnustone in rats. The sample was precipitated with acetonitrile with 0.5% formic acid and separated on BEH C18 Column. The mobile phase was composed of 0.1% formic acid in water and methanol at a flow rate of 0.3 mL/min. Alnustone and the internal standard (caffeine) were quantitatively monitored with precursor-to-product ion transitions of m/z 262.9→105.2 and m/z 195.2→138.0, respectively. The calibration curve for alnustone was linear from 1 to 2000 ng/mL. The intra- and inter-day assay precision (RSD) ranged from 1.1-9.0 % to 3.3-8.6%, respectively and the intra- and inter-day assay accuracy (RE) was between -8.2-9.7% and -10.3-9.9%, respectively. The validated method was successfully applied to the pharmacokinetic studies of alnustone in rats. After single-dose intravenous administration of alnustone (5 mg/kg), the mean peak plasma concentration (Cmax) value was 7066.36 ± 820.62 ng/mL, and the mean area under the concentration-time curve (AUC0-t) value was 6009.79 ± 567.30 ng/mL∙h. Our results demonstrated that the residence time of alnustone in vivo was not long and it eliminated quickly from the rat plasma. Meanwhile, the drug is mainly distributed in tissues with large blood flow, and the lung and liver might be the target organs for alnustone efficacy. The study will provide information for further application of alnustone.