The effect of L-proline as a promoter on the condensation reaction of salicylaldehyde or its derivatives with ethyl acetoacetate in neutral ionic liquid [emim]BF4 was studied. All reactions were carried out under mild reaction conditions and achieved high yields. Moreover, the ionic liquid containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity. The results show that the L-proline-[emim]BF4 system has a potential in contribution to the development of environmentally friendly and inexpensive processes in organic syntheses.
Coumarins ; chemical synthesis ; Ionic Liquids ; chemistry ; Proline ; chemistry

In this paper, fourteen new L-proline derivatives were designed and synthesized, and their acetlcholinesterase (AChE) inhibitory activities were also investigated in vitro. New L-proline derivatives were prepared from substituted 2-bromo-1-acetophenones through four-step reaction; and their bioactivities as AChE inhibitors were measured by Ellman spectrophotometry. The results showed that the target compounds had a certain AChE inhibitory activity to in vitro. The bioactivity of compound 8b was the best of them, and its IC50 value was 5.45 µmol.L-1, which was better than that of rivastigmine. So the acetylcholinesterase inhibitory activities of new L-proline derivatives were worth to be further studied.
Acetylcholinesterase ; Cholinesterase Inhibitors ; chemical synthesis ; chemistry ; Drug Design ; Proline ; analogs & derivatives ; Rivastigmine ; chemistry ; Structure-Activity Relationship

This study developed an optimal pre-processing technique for the reference substance of the classic formula Gualou Xiebai Banxia Decoction(GXBD) and established a comprehensive quality control method for GXBD reference substance to provide a reference for its overall quality evaluation. The authors prepared 15 batches of GXBD samples and innovatively used the extracted ion chromatogram under the base peak chromatogram mode to establish a liquid chromatography-mass spectrometry(LC-MS) fingerprint, identify characteristic peaks, and perform quantitative analysis of indicator components. The yield of the 15 batches of GXBD samples ranged from 50.28% to 76.20%. In the positive ion mode, 12 common characteristic peaks were detected in the LC-MS fingerprint, and the structures of five common peaks were identified by comparison with reference standards. The similarity between the fingerprint profiles of different batches of samples and the reference fingerprint profile ranged from 0.920 to 0.984. Finally, liquid chromatography-triple quadrupole mass spectrometry(LC-QQQ/MS) in multiple reaction monitoring(MRM) mode was used to determine the content of eight indicator components in GXBD, including loliolide, chrysoeriol, rutin, cucurbitacin D, macrostemonoside Ⅰ, 25S-timosaponin B Ⅱ, 25R-timosaponin B Ⅱ, and peptide proline-tryptophan-valine-proline-glycine(PWVPG). The method established in this study can reduce matrix interference in the compound, and it has good accuracy, stability, and practical value. It effectively reflects the quality attributes of GXBD samples and can be used for the comprehensive quality control of GXBD.
Chromatography, Liquid ; Tandem Mass Spectrometry/methods* ; Drugs, Chinese Herbal/chemistry* ; Proline ; Chromatography, High Pressure Liquid/methods*

OBJECTIVETo establish a method to determine the underivatized glycine (Gly) and proline (Pro) in vinegar turtle shell.

METHODAn HPLC-ELSD method was conducted on a Prevail C18 column (4.6 mm x 250 mm, 5 microm) with the mobile phase of acetonitrile and 0.7% trifluoroacetic acid solution (containing 5.0 mmol x L(-1) heptafluorobutyric acid), and elution time was 15 min.

RESULTThe calibration curves were showed good linearity within the concentration range of 0.14-0.6 g x L(-1). The average recoveries were 101.2% and 102.5%, and RSD were 1.9% and 2.5%, respectively.

CONCLUSIONSince this method needs neither the special amino acid analyzer nor derivation of amino acid., it is efficient, simple and accurate., which could be used for quality control of vinegar turtle shell.

Animal Shells ; chemistry ; Animals ; Chromatography, High Pressure Liquid ; Glycine ; analysis ; Proline ; analysis ; Quality Control ; Reference Standards ; Reproducibility of Results ; Turtles

OBJECTIVETo establish a new method for determining norepinephrine (NE) in the presence of epinephrine and ascorbic acid using proline-modified glassy carbon electrode (GCE).

METHODSIn phosphate buffer solution (pH 9.0), the poly-proline-modified electrode was prepared by cyclic voltammetry method. The voltammetric behavior of NE on poly(proline) film were analyzed to establish a electrochemical analysis method for determination of NE on the modified electrode.

RESULTSIn PBS (pH 7.0), a couple of redox peaks of NE was observed on the modified electrode. The modified electrode was used to determine NE in a excess of epinephrine (EP) and ascorbic acid (AA) by reduction peak current of cyclic voltammetry. The reduction peak currents were in linear relationship with the NE concentrations within the range of 7.0 x 10(-7) to 1.1 x 10(-4) mol/L, with the detection limit of 6.0x10(-8) mol/L.

CONCLUSIONThe modified electrode shows good sensitivity, selectivity, and stability for NE determination, and is well applicable for analysis of injection solution samples.

Ascorbic Acid ; analysis ; Biosensing Techniques ; instrumentation ; methods ; Carbon ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Electrochemistry ; instrumentation ; methods ; Epinephrine ; analysis ; Humans ; Microelectrodes ; Norepinephrine ; analysis ; Proline ; chemistry ; Reproducibility of Results

Ecdysis is a common phenomenon that happens throughout the life phase of the giant freshwater prawn Macrobrachium rosenbergii. It is vital to better understand the correlation between cannibalism and biochemical compound that exists during the moulting process. The objective of the present study was to determine the amino acid profile released by M. rosenbergii during the ecdysis process that promotes cannibalism. To accomplish this, changes in amino acid levels (total amino acid (TAA) and free amino acid (FAA)) of tissue muscle, exoskeleton, and sample water of culture medium from the moulting (E-stage) and non-moulting (C-stage) prawns were analysed using high-performance liquid chromatography (HPLC). Comparison study revealed that among the TAA compounds, proline and sarcosine of tissues from moulting prawn were found at the highest levels. The level of FAA from water that contains moulting prawns (E-stage) was dominated by tryptophan and proline. Significant values obtained in the present study suggested that these amino acid compounds act as a chemical cue to promote cannibalism in M. rosenbergii during ecdysis. The knowledge of compositions and compounds that were released during the moulting process should be helpful for better understanding of the mechanism and chemical cues that play roles on triggering cannibalism, and also for future dietary manipulation to improve feeding efficiencies and feeding management, which indirectly impacts productivity and profitability.
Amino Acids/chemistry* ; Animals ; Aquaculture ; Cannibalism ; Chromatography, High Pressure Liquid ; Feeding Behavior ; Fresh Water ; Malaysia ; Molting ; Palaemonidae/physiology* ; Proline/chemistry* ; Tryptophan/chemistry*

Even though chemistry is now in place that potentially allows high coupling efficiencies to be attained, successful coupling is usually a challenge when so-called "difficult sequences" is encountered in peptide synthesis. Some factors that affect the coupling efficiency have been discussed and related methods to overcome those obstacles have been introduced in present review. All suggestions proposed here are valuable and also feasible to improve the coupling completeness in both liquid-phase or solid-phase
Acylation ; Amino Acid Sequence ; Molecular Structure ; Organophosphorus Compounds ; chemistry ; Peptide Fragments ; chemical synthesis ; chemistry ; Peptides ; chemical synthesis ; chemistry ; Proline ; analogs & derivatives ; chemistry ; Resins, Synthetic ; chemistry ; Temperature ; Thiazoles ; chemistry ; Thiocyanates ; chemistry ; Triazoles ; chemistry

AIMTo identify the main metabolites of stachydrine in rat.

METHODSThe ionization, cleavage and chromatographic characteristics of stachydrine were studied by using high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry (HPLC-ESI/MS) for the first time. These characteristics of stachydrine were used as the basis for the analyses of metabolites in rat urine. The 0 - 24 h urine samples of rats after ig 25 mg x kg(-1) stachydrine were collected and purified by using C10 solid-phase extraction cartridge, and then analyzed by HPLC-ESI/MS to identify stachydrine and its metabolites.

RESULTSThe parent drug (stachydrine), 6 phase I metabolites (N-demethyl, dehydrogenation, ring-oxidation) and 2 phase II metabolites (glycine conjugates of 2 ring-oxidation products) were identified existing in rat urine.

CONCLUSIONThe presented method was proved to be sensitive, rapid, high selective and specific for the identification of stachydrine and its metabolites in rat urine.

Animals ; Chromatography, High Pressure Liquid ; methods ; Plant Roots ; chemistry ; Plants, Medicinal ; chemistry ; Proline ; analogs & derivatives ; isolation & purification ; metabolism ; urine ; Rats ; Rats, Wistar ; Sensitivity and Specificity ; Spectrometry, Mass, Electrospray Ionization ; methods ; Stachys ; chemistry

The quality and grade of traditional Chinese medicinal herbs were assessed by their characteristics traditionally. According to traditional experience, the quality of the purple Flos Farfarae is better than that of yellow buds. NMR-based metabolomic approach combined with significant analysis of microarray (SAM) and Spearman rank correlation analysis were used to investigate the different metabolites of the Flos Farfarae with different color feature. Principal component analysis (PCA) showed clear distinction between the purple and yellow flower buds of Tussilago farfara. The S-plot of orthogonal PLS-DA (OPLS-DA) and t test revealed that the levels of threonine, proline, phosphatidylcholine, creatinine, 4, 5-dicaffeoylquinic acid, rutin, caffeic acid, kaempferol analogues, and tussilagone were higher in the purple flower buds than that in the yellow buds, in agreement with the results of SAM and Spearman rank correlation analysis. The results confirmed the traditional medication experience that "purple flower bud is better than the yellow ones", and provide a scientific basis for assessing the quality of Flos Farfarae by the color features.
Caffeic Acids ; analysis ; Color ; Creatinine ; analysis ; Flowers ; chemistry ; Kaempferols ; analysis ; Magnetic Resonance Spectroscopy ; Metabolomics ; Phosphatidylcholines ; analysis ; Plants, Medicinal ; chemistry ; Principal Component Analysis ; Proline ; analysis ; Quinic Acid ; analogs & derivatives ; analysis ; Rutin ; analysis ; Sesquiterpenes ; analysis ; Threonine ; analysis ; Tussilago ; chemistry

OBJECTIVEOptimize the technic condition of Duzhong Jiangya prescription with Semi-bionic Extraction.

METHODUsing homogeneous design, under the same materials granularity, decoction temperature, consumption of water, filtration, concentration, and taking aucubin, hydrochloric acid stachydrine, maloicacid, baicalin, ethanol extract, dry extract as the indexes, the results were comprehensive considered to optimize the semi-bionic extraction condtions.

RESULTThe optimized SBE extraction conditions are the following: pH values of the water for the thrice extraction is 5.845 3, 7.496 1, 8.011 7, and the total extraction time is 3.418 0 h.

CONCLUSIONConsidering the fact of manufacture, the SBE extraction conditions are the following: pH values of the water for the thrice extraction is 6.0, 7.5, 8.0, and the thrice extraction time is 1.5, 1.0, 1.0 h.

Antihypertensive Agents ; chemistry ; isolation & purification ; Drug Combinations ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Eucommiaceae ; chemistry ; Flavonoids ; analysis ; Glucosides ; analysis ; Hydrogen-Ion Concentration ; Iridoid Glucosides ; Iridoids ; analysis ; Leonurus ; chemistry ; Plants, Medicinal ; chemistry ; Proline ; analogs & derivatives ; analysis ; Prunella ; chemistry ; Scutellaria baicalensis ; chemistry ; Technology, Pharmaceutical ; methods ; Time Factors ; Triterpenes ; analysis ; Uncaria ; chemistry