Wettability behavior of DTMS modified SiO2: Experimental and molecular dynamics study.

In this research, the wetting behavior of SiO2 modified with dodecyltrimethoxysilane (DTMS) was explored using both experimental and molecular dynamics (MD) simulation approaches. The experimental results reveal that DTMS can chemically bond to the SiO2 surface, and the contact angle (CA) reaches the maximum value of 157.7° when the mass of DTMS is twice that of SiO2. The different wetting behaviors caused by DTMS grafting were analyzed by CA fitting, ionic pairs, concentration distribution, molecule orientation, and interfacial interaction energy. The results demonstrate that a 25 % DTMS grafting rate resulted in a maximum CA of 158.2°, which is ascribed to the disruption of interfacial hydrogen bonding and changes in the hydration structure caused by DTMS grafting. Moreover, the above hydrophobic SiO2 model shows a slight decrease in CA as the water temperature increases, which is consistent with the experimental findings. In contrast, an opposite change was observed for the pristine SiO2 model. Although the higher water temperature enhances the diffusion capacity of water molecules in both models, the difference in interfacial interactions is responsible for the change in CA. We hope this finding will contribute to a deeper understanding of the wetting adjustment of SiO2.

Molecular dynamics study of the corrosion protection improvement of superhydrophobic dodecyltrimethoxysilane film on mild steel.

Recently, superhydrophobic surfaces have received increasing interest in metal corrosion protection due to their excellent waterproofing characteristics. However, little attention has been paid to the related anti-corrosion mechanism at the molecular level. In this work, the protection behaviors provided by the superhydrophobic dodecyltrimethoxysilane for mild steel were first explored using molecular dynamics (MD) simulation in terms of silane absorption orientations and water cluster wetting behaviors. The results show that the conformations of dodecyltrihydroxysilane (DTHS) on the Fe substrate are greatly dependent on the solvent environment. Typically, the DTHS molecule adopts a "standing" orientation with the hydrophilic head attached to the Fe surface and the hydrophobic tail remaining in the polar phase, which is conducting to generate a good repulsive effect on the water droplet. Based on this, the diffusion performance of corrosive species in the superhydrophobic DTHS film was further investigated. The computational results indicate that the corrosive species are confined to specific regions of the film, which results in a decreased diffusion coefficient. Additionally, the weak movement of DTHS molecules also increases the transport resistance of the corrosive medium through the superhydrophobic DTHS film, thereby improving the corrosion protection of the underlying metal substrate. The results obtained in this work will deepen our understanding of the anticorrosion mechanism of superhydrophobic silane films.

Baicalin attenuated metabolic dysfunction-associated fatty liver disease by suppressing oxidative stress and inflammation via the p62-Keap1-Nrf2 signalling pathway in db/db mice.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the main cause of chronic liver disease. Baicalin (Bai), a bioactive molecule found in Scutellaria baicalensis Georgi, possesses antioxidant and antiinflammatory properties. These activities suggest Bai could be a promising therapeutic agent against NAFLD; however, its specific effects and underlying mechanism are still not clear. This study aims to explore the effect of Bai to attenuate MAFLD and associated molecular mechanisms. Bai (50, 100 or 200 mg/kg) was orally administered to db/db mice with MAFLD for 4 weeks or db/m mice as the normal control. Bai markedly attenuated lipid accumulation, cirrhosis and hepatocytes apoptosis in the liver tissues of MAFLD mice, suggesting strong ability to attenuate MAFLD. Bai significantly reduced proinflammatory biomarkers and enhanced antioxidant enzymes, which appeared to be modulated by the upregulated p62-Keap1-Nrf2 signalling cascade; furthermore, cotreatment of Bai and all-trans-retinoic acid (Nrf2 inhibitor) demonstrated markedly weakened liver protective effects by Bai and its induced antioxidant and antiinflammatory responses. The present study supported the use of Bai in attenuating MAFLD as a promising therapeutic agent, and its strong mechanism of action in association with the upregulating the p62-keap1-Nrf2 pathway.

MS-based metabolite analysis of two licorice chalcones in mice plasma, bile, feces, and urine after oral administration.

Isoliquiritigenin (ILG) and isoliquiritin (ILQ), two kinds of major flavonoids in licorice, are biological active substances with antioxidant, anti-inflammatory, and tumor-suppressive effects. However, their in vivo metabolites, possible material basis of this two licorice chalcones for the treatment of diseases, have not been studied completely. To determine the metabolism of ILG and ILQ, after oral administration of 100 mg/kg/day of these compounds for consecutive 8 days, the metabolites of these two licorice chalcones in mice plasma, urine, feces, and bile were determined using liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry in this study. The structures of those metabolites were tentatively identified according to their fragment pathways, accurate masses, characteristic product ions, metabolism law, and reference standards-matching. As a result, a total of 25 and 29 metabolites of ILG and ILQ were identified, respectively. Seven main metabolic pathways, oxidation and reduction, deglycosylation and glycosylation, dehydroxylation and hydroxylation, demethoxylation and methoxylation, acetylation, glucuronidation, and sulfation, were summarized to tentatively explain how the metabolites were biologically transformed. These results provide the important information on the metabolism of ILG and ILQ, which may be helpful for the further research of their pharmacological mechanism.

Metabolic profiling of mice plasma, bile, urine and feces after oral administration of two licorice flavonones.

ETHNOPHARMACOLOGICAL RELEVANCE: Licorice is an ancient food and medicinal plant. Liquiritigenin and liquiritin, two kinds of major flavonoes in licorice, are effective substances used as antioxidant, anti-inflammatory and tumor-suppressive food, cosmetics or medicines. However, their in vivo metabolites have not been fully explored. AIM OF STUDY: To clarify the metabolism of liquiritigenin and liquiritin in mice. MATERIALS AND METHODS: In this study, we developed a liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry approach to determine the metabolites in mice plasma, bile, urine and feces after oral administration of liquiritigenin or liquiritin. The structures of those metabolites were tentatively identified according to their fragment pathways, accurate masses, characteristic product ions, metabolism laws or reference standard matching. RESULTS: A total of 26 and 24 metabolites of liquiritigenin or liquiritin were respectively identified. The products related with apigenin, luteolin or quercetin were the major metabolites of liquiritigenin or liquiritin in mice. Seven main metabolic pathways including (de)hydrogenation, (de)hydroxylation, (de)glycosylation, (de)methoxylation, acetylation, glucuronidation and sulfation were summarized to tentatively explain their biotransformation. CONCLUSION: This study not only can provide the evidence for in vivo metabolites and pharmacokinetic mechanism of liquiritigenin and liquiritin, but also may lay the foundation for further development and utilization of liquiritigenin, liquiritin and then licorice.

Metabolomics Study of Metabolic Changes in Renal Cells in Response to High-Glucose Exposure Based on Liquid or Gas Chromatography Coupled With Mass Spectrometry.

Diabetic nephropathy (DN) is one of the most serious microvascular complications and the leading causes of death in diabetes mellitus (DM). To find biomarkers for prognosing the occurrence and development of DN has significant clinical value for its prevention, diagnosis, and treatment. In this study, a non-targeted cell metabolomics-based ultra-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry and gas chromatography coupled with mass spectrometry was developed and performed the dynamic metabolic profiles of rat renal cells including renal tubular epithelial cells (NRK-52E) and glomerular mesangial cells (HBZY-1) in response to high glucose at time points of 12 h, 24 h, 36 h, and 48 h. Some potential biomarkers were then verified using clinical plasma samples collected from 55 healthy volunteers, 103 DM patients, and 57 DN patients. Statistical methods, such as principal component analysis and partial least squares to latent structure-discriminant analysis were recruited for data analyses. As a result, palmitic acid and linoleic acid (all-cis-9,12) were the potential indicators for the occurrence and development of DN, and valine, leucine, and isoleucine could be used as the prospective biomarkers for DM. In addition, rise and fall of leucine and isoleucine levels in plasma could be used for prognosing DN in DM patients. Through this study, we established a novel non-targeted cell dynamic metabolomics platform and identified potential biomarkers that may be applied for the diagnosis and prognosis of DM and DN.