Untargeted and targeted mass spectrometry reveal the effects of theanine on the central and peripheral metabolomics of chronic unpredictable mild stress-induced depression in juvenile rats

L-theanine has been shown to have a therapeutic effect on depression.However,whether L-theanine has an excellent preventive effect on depression in children and adolescents and what its mechanism is have not been well explained.Given the complexity of the pathogenesis of depression,this study investigated the preventive effect and mechanism of L-theanine on depression in juvenile rats by combining serum and hippocampal metabolomic strategies.Behavioral tests,hippocampal tissue sections,and serum and hippocampal biochemical indexes were studied,and the results confirmed the preventive effect of Ltheanine.Untargeted reversed-phase liquid chromatography-quadrupole-time-of-flight mass spectrometry and targeted hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry were developed to analyze the metabolism changes in the serum and hippocampus to screen for potential biomarkers related to L-theanine treatment.The results suggested that 28 abnormal metabolites in the serum and hippocampus that were considered as potential biomarkers returned to nearnormal levels after L-theanine administration.These biomarkers were involved in various metabolic pathways,mainly including amino acid metabolism and lipid metabolism.The levels of amino acids and neurotransmitters in the phenylalanine,tryptophan,and glutamic acid pathways were significantly reduced after L-theanine administration compared with chronic unpredictable mild stress-induced rats.In summary,L-theanine had a significant preventive effect on depression and achieved its preventive results on depression by regulating various aspects of the body,such as amino acids,lipids,and inflammation.This research systematically analyzed the mechanism of L-theanine in preventing depression and laid the foundation for applying L-theanine to prevent depression in children and adolescents.

Analysis of pesticide residues in commercially available chenpi using a modified QuEChERS method and GC-MS/MS determination

To ensure the safety of the commercially available chenpi,a convenient and fast analytical method was developed for the determination of 133 pesticide residues in chenpi using gas chromatography-tandem mass spectrometry(GC-MS/MS).In this study,different extraction solvents,redissolution solvents and adsorbents were tested according to the recovery and purification effect to obtain a modified QuEChERS method.The samples were extracted with acetonitrile.During the clean-up step,octadecyl-modified silica(C18)and graphitized carbon black(GCB)were selected,and aminopropyl(NH2)was used instead of primary secondary amine(PSA)because of its weaker ion exchange capacity which had little effect on the recovery of ditalimfos.Samples were quantified by matrix-matched calibration with internal standards.All pesticides showed good linearity in the respective range,both with values of r2>0.99.The average recoveries of the pesticides spiked samples ranged from 70.0% to 112.2% with the RSDs of 0.2%–14.4%.The modified QuEChERS method was validated and applied to twenty real samples.Five pesticides were found in eight batches,but no pesticide exceeded the maximum residue limits(MRL,MRL reference to European commission).

Metabonomic analysis of plasma biochemical changes in pyrexia rats after treatment with Gegenqinlian decoction,aspirin and itraconazole by UHPLC-FT-ICR-MS

A metabonomic approach involving an ultrahigh-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry(UHPLC-FT-ICR-MS)was used to investigate the changes in the endogenous metabolites in the plasma of rats with yeast-induced pyrexia treated with Gegenqinlian decoction(GQLD),aspirin and itraconazole.The differences in the small molecule profiles of treatment using traditional Chinese medicine,etiological treatment and symptomatic treatment were elucidated.Thirty-six plasma metabolites were identified or putatively identified,and the effects of the three medicines on the thirty-six metabolites were studied.Their metabolic pathways indicated that GQLD,aspirin and itraconazole ameliorated the rats with yeast-induced pyrexia predominantly by regulating the metabolisms of phospholipid,sphingolipid,fatty acid oxidation,fatty acid amides,amino acid and glycerolipid in vivo.The pharmacodynamics and metabonomic results showed that the three medicines exhibited the therapeutic effects on pyrexia by regulating the perturbations of multiple metabolisms.The study provided a scientific basis for an in-depth understanding of the therapeutic effects of GQLD,aspirin and itraconazole on rats with yeast-induced pyrexia.

Composition analysis and antioxidant activities of the Rhus typhina L.stem

The present investigation reports the chemical composition of the Rhus typhina L. stem identified via mass spectrometry and NMR as gallic acid, 1-O-galloyl-β-D-glucose, tryptophan, scopolin, methyl gallate, fustin, quercetin, rutin, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose. The antioxidant properties and the chemical composition contents of the R. typhina L. stem grown in different regions in China were determined. To determine the antioxidant activity, a total phenolic content analysis, 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity assay, ferric reducing antioxidant power assay, and β-carotene linoleic acid model system were conducted. The results showed that the Rhus typhina L. stem possessed high antioxidant capacities due to its high phenolic content. The contents of the nine isolated compounds were determined by UPLC-ESI-MS/MS. The calibration curves of the nine isolated compounds were linear within the concentration range and the average recoveries were high. The result showed that 1-Ogalloyl-β-D-glucose, gallic acid, methyl gallate, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose could be the compounds mainly responsible for the antioxidant capacity of the R. typhina L. stem. This reveals that the R. typhina L. stem is a good source of antioxidants.

Species authentication and geographical origin discrimination of herbal medicines by near infrared spectroscopy:A review

Near infrared （NIR） spectroscopy as a rapid and nondestructive analytical technique, integrated with chemometrics, is a powerful process analytical tool for the pharmaceutical industry and is becoming an attractive complementary technique for herbal medicine analysis. This review mainly focuses on the recent applications of NIR spectroscopy in species authentication of herbal medicines and their geo- graphical origin discrimination.

Study on chemical composition of Viscum coloratum and its HPLC fingerprint in different harvest periods

The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical analysis,and to determine the optimal harvest time of Viscum coloratum.8 compounds were isolated from Viscum coloratum by a variety of isolation techniques,3 of which were isolated from the genus Viscum L.for the first time.The fingerprint of Viscum coloratum was established by HPLC,and 16 common peaks were obtained,4 of which were identified by comparison with the reference substances.Results showed that the Viscum coloratum harvested in 6 months could be roughly divided into three groups based on the chemical profiles,and the Viscum coloratum harvested in January had higher levels of the marked compounds.The HPLC fingerprint objectively reveals the characteristics of Viscum coloratum harvested in different months,which can be used to evaluate and control the quality of Viscum coloratum harvested in different months.

Determination of atractylon in rat plasma by a GC-MS method and its application to a pharmacokinetic study

A sensitive and selective method based on gas chromatography hyphenated to mass spectrometry （GC- MS） was developed and validated for the determination of atractylon in rat plasma. Plasma samples were processed by liquid-liquid extraction with ethyl acetate-n-hexane （1：1, v/v） using acetophenone as an internal standard （IS）. Analytes were determined in selective ion monitoring （SIM） mode using target ions at m/z 108.1 for atractylon and m/z 105.1 for acetophenone. The calibration curve was linear over the concentration range of 10-1000 ng/mL with lower limit of quantification of 10 ng/mL. The intra- and inter-day precision variations were not more than 10.4% and 9.6%, respectively, whilst accuracy values ranged from -6.5% to 4.9%. Extraction recovery of the assay was satisfactory. This method was suc- cessfully applied to quantification and pharmacokinetic study of atractylon in rat plasma after in- tragastric administration of Atractvlodis extract.

Influence of light absorption on the metallic nanotextured reflectors of GaN-based light emitting diodes

Metallic nanotextured reflectors have been widely used in light emitting diodes(LEDs) to enhance the light extraction efficiency. However, the light absorption loss for the metallic reflectors with nanotexture structure is often neglected. Here, the influence of absorption loss of metallic nanotextured reflectors on the LED optoelectronic properties were studied. Two commonly used metal reflectors Ag and Al were applied to green GaN-based LEDs. By applying a Ag nanotextured reflector, the light output power of the LEDs was enhanced by 78% due to the improved light extraction. For an Al nanotextured reflector, however,only a 6% enhancement of the light output power was achieved. By analyzing the metal absorption using finite-difference timedomain(FDTD) and the metal reflectivity spectrum, it is shown that the surface plasmon(SP) intrinsic absorption of metallic reflectors with nanotexture structure play an important role. This finding will aid the design of the high-performance metal nanotextured reflectors and optoelectronics devices.

A rapid and sensitive liquid chromatography–tandem mass spectrometric method for the determination of hederasaponin B in rat plasma: Application to a pharmacokinetic study

A rapid, simple and sensitive ultra-high performance liquid chromatography–tandem mass spectrometric(UPLC–MS/MS) method was developed and validated for the determination of hederasaponin B, an active triterpenoid saponin widely existed in Hedera helix L. Plasma samples were processed by protein precipitation with acetonitrile and separated on a Thermo Hypersil GOLD C18(2.1 mm × 50 mm,1.9 μm) at flow rate of 0.3 ml/min, with a gradient elution consisting of acetonitrile and water containing 0.1%(v/v) formic acid at 30 ℃ and detected by electrospray ionization mass spectrometry in the positive multiple reaction monitoring(MRM) mode. The linearity was found to be within the concentration range of 0.5–5000 ng/ml with a lower limit of quantification of 0.5 ng/ml. The absolute oral bioavailability of hederasaponin B was 0.24 ± 0.49%. This indicated that the concentration-time course of the hederasaponin B existed a double-peak phenomenon. This method was further applied to the determination of hederasaponin B in rat plasma and showed good practicability, for the first time, after intragastric(25 mg/kg) and intravenous(2 mg/kg) administration in rats.

Prediction of the Slope Solute Loss Based on BP Neural Network

The existence of soil macropores is a common phenomenon.Due to the existence of soil macropores,the amount of solute loss carried by water is deeply modified,which affects watershed hydrologic response.In this study,a new improved BP(Back Propagation)neural network method,using Levenberg–Marquand training algorithm,was used to analyze the solute loss on slopes taking into account the soil macropores.The rainfall intensity,duration,the slope,the characteristic scale of macropores and the adsorption coefficient of ions,are used as the variables of network input layer.The network middle layer is used as hidden layer,the number of hidden nodes is five,and a tangent transfer function is used as its neurons transfer function.The cumulative solute loss on the slope is used as the variable of network output layer.A linear transfer function is used as its neurons transfer function.Artificial rainfall simulation experiments are conducted in indoor experimental tanks in order to verify this model.The error analysis and the performance comparison between the proposed method and traditional gradient descent method are done.The results show that the convergence rate and the prediction accuracy of the proposed method are obviously higher than that of traditional gradient descent method.In addition,using the experimental data,the influence of soil macropores on slope solute loss has been further confirmed before the simulation.

A validated reversed phase HPLC method for determination of process-related impurities in DHDK-loaded mPEG-PLA micelles

A new compound named DHDK was isolated from Viscum coloratum and identified as (1E,4E)-1,7-bis(4-hydroxyphenyl)hepta -1,4-dien-3-one. DHDK, a new potential anti-tumor drug, was synthesized and prepared poly(ethylene glycol)-poly(D.L-lactic acid)(mPEG-PLA) micelles due to cytotoxic effects on a range of cancer cells. A revered phase liquid chromatographyic method has been developed and validated for the determination of potential related impurities in DHDK-loaded mPEG-PLA micelles. The micelles was subjected to the stress conditions of acid, base, oxidation, thermal and photolysis. The determination was achieved on Phenomenex SynergiTM 4 μm Fusion-RP 80?(250 mm × 4.6 mm, 4 μm) with a gradient elution and the detection wavelength was set at 220 nm. Regression analysis shows as r value (correlation coefficient) of greater than 0.999 for DHDK and six potential impurities. Recoveries of impurities were found between 90.0% and 108.0%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness, which can be used for determination of related impurities in DHDK-loaded mPEG-PLA micelles.

GaN-based LEDs for light communication

Rapid improvement in the efficiency of GaN-based LEDs not only speed up its applications for general illumination, but offer the possibilities for data transmission. This review is to provide an overview of current progresses of GaN-based LEDs for light communications. The modulation bandwidth of GaN-based LEDs has been first improved by optimizing the LED epilayer structures and the modulation bandwidth of 73 MHz was achieved at the driving current density of 40 A/cm2 by changing the multi-quantum well structures. After that, in order to increase the current density tolerance, different parallel flip-chip micro-LED arrays were fabricated. With a high injected current density of ~7900 A/cm2, a maximum modulation bandwidth of ~227 MHz was obtained with optical power greater than 30 mW. Besides the increase of carrier concentrations, the radiative recombination coefficient B was also enhanced by modifying the photon surrounding environment based on some novel nanostructures such as resonant cavity, surface plasmon, and photonic crystals. The optical 3 dB modulation bandwidth of GaN-based nanostructure LEDs with Ag nanoparticles was enhanced by 2 times compared with GaN-based nanostructure LEDs without Ag nanoparticles.Our results demonstrate that using the QW-SP coupling can effectively help to enhance the carrier spontaneous emission rate and also increase the modulation bandwidth for LEDs, especially for LEDs with high intrinsic IQE. In addition, we discuss the progress of the faster color conversion stimulated by GaN-based LEDs.