[Evaluation of nutritional value of Bambusae Concretio Silicea based on content of 15 amino acids].

The content of 15 total amino acids(TAAs) in Bambusae Concretio Silicea was determined by HPLC with phenyl-isothiocyanate(PITC) for pre-column derivatization. The results showed that the content of TAA was 0.61-12.25 mg·g~(-1), and aspartic acid(Asp), glutamic acid(Glu), proline(Pro), glycine(Gly), and valine(Val) were the top five amino acids in terms of the average content. The content of essential amino acids(EAAs), conditionally essential amino acids(CEAAs), non-essential amino acids(NEAAs), and medicinal amino acids(MAAs) was 0.24-4.75, 0.30-4.73, 0.40-7.50, and 0.36-6.51 mg·g~(-1), respectively. Among the delicious amino acids, sweet amino acids(SAA), bitter amino acids(BAA), fresh-taste amino acids(FAAs), and odourless amino acids(OAAs) had the content of 0.22-4.70, 0.19-4.03, 0.13-2.26, and 0.06-1.26 mg·g~(-1), respectively. The 21 batches of Bambusae Concretio Silicea samples presented the same composition but significant differences in the content of amino acids. Among the three producing areas, Guangdong was the area where the samples had the highest content of TAAs, EAAs, CEAAs, NEAAs, MAAs, and delicious amino acids. Furthermore, the ratio of amino acid(RAA), ratio coefficient of amino acid(RCAA), and score of ratio coefficient of amino acid(SRCAA) were calculated to evaluate the nutritional value of Bambusae Concretio Silicea. The results showed that the Bambusae Concretio Silicea samples from Guangdong had better nutritional value. The nutritional value evaluation based on the content of 15 amino acids was proposed to provide data support for the quality grading of Bambusae Concretio Silicea and lay a foundation for the development and utilization of the medicinal material resources.

A novel integrated automatic strategy for amino acid composition analysis of seeds from 67 species.

The composition and quantity of amino acids (AAs) in seeds are complicated due to the various origins and modifications of different species. In this study, a novel automatic neutral loss filtering (ANLF) strategy based on accurate mass searching by Python was developed to analyze the free and hydrolyzed AA-phenyl isothiocyanate (PITC) derivatives from seeds of Gymnosperm and Angiosperm phyla. Compared with traditional strategies, ANLF showed much higher accuracy in screening AA derivatives by filtering nitrogen-containing non-AA compounds and efficiency in processing large datasets. Meanwhile, the content phenotype of 20 proteinogenic AAs from seeds of these two families was characterized by a 35-min HPLC method combined with an automated peak-matching strategy. AA profiles of 232 batches of seeds from 67 species, consisting of 19 proteinogenic AAs, 21 modified AAs, and 77 unknown AAs, would be a good reference for their application in food and medicine.

Synthesis and Evaluation of Thioamide and Bromo Derivatives of 1,3-Diphenylpropane-1,3-dione as 5α-Reductase Inhibitors.

BACKGROUND: 1,3-Diphenylpropane-1,3-dione (1) is an acetylacetone ß-diketone in which both of the methyl groups have been replaced with phenyl groups. It is a component of licorice root extract (Glycyrrhiza glabra) and has anti-mutagenic and anti-cancer properties. It functions as a metabolite, an anti-mutagen, and an anti-neoplastic agent. It is an aromatic ketone and a ß-diketone. 1,3-Diphenylpropane-1,3-dione (1) is primarily used in PVC hard and soft materials, including plates, films, profiles, pipes, and fittings. OBJECTIVES: This research aims to examine the utility of 1,3-diphenylpropane-1,3-dione (1) for the synthesis of a variety of new heterocyclic compounds, such as thioamide, thiazolidine, thiophene-2-carbonitrile, phenylthiazole, thiadiazole-2-carboxylate, 1,3,4-thiadiazole derivatives, 2-bromo-1,3-diphenylpropane-1,3-dione, new substituted benzo[1,4]thiazines, phenylquinoxalines, and imidazo[1,2-b][1,2,4]triazole derivatives of potential biological activity Methods: 1,3-Diphenylpropane-1,3-dione (1) was used as a starting compound for the synthesis of 3-oxo-N,3-diphenyl-2-(phenylcarbonyl)propanethioamide (3) and 2-bromo-1,3-diphenylpropane-1,3-dione (25), which can be used for further preparations. The 5α-reductase inhibitor activity of some of the synthesized compounds was also tested in vivo; the ED50 and LD50 data were established, Results: Using IR, 1H-NMR, mass spectroscopy, and elemental analysis, the structures of all produced compounds were elucidated. Some of these prepared compounds were reported as 5α-reductase inhibitors. CONCLUSION: New heterocyclic compounds can be formed via 1,3-diphenylpropane-1,3-dione (1), and some of these compounds can act as 5α-reductase inhibitors.

The Selection of the Best Derivatization Reagents for the Determination of Polyamines in Home-Made Wine Samples.

The procedures of putrescine, spermine, spermidine, and cadaverine derivatization using 2-chloro-1,3-dinitro-5-(trifluoromethyl)benzene, 1-fluoro-2-nitro-4-(trifluoromethyl) benzene, and 3,5-bis-(trifluoromethyl)phenyl isothiocyanate for chromatographic determination in home-made wine samples are compared in the present study. The procedures discussed were compared regarding simplicity, linearity, precision, and accuracy. The polyamines derivatives were isolated and characterized by X-ray crystallography and 1H, 13C, and 19F NMR spectroscopy. The obtained structures of aliphatic amines showed that all amino groups, four in spermine, two in putrescine and cadaverine, and three in spermidine, regardless of the applied reagent, were substituted. The applicability of the described procedures was tested during the chromatographic analysis of the compounds' content in home-made wines. For this purpose, a simple and environmentally friendly sample preparation procedure was developed. The obtained results present the derivatization of polyamines with 1-fluoro-2-nitro-4-(trifluoromethyl)benzene as a better choice for the determination of these compounds in food samples.

Detection of Balenine in Mouse Plasma after Administration of Opah-Derived Balenine by HPLC with PITC Pre-Column Derivatization.

We examined the absorption of balenine (Bal) in mouse blood after the administration of a high-purity Bal prepared from opah muscle. Using HPLC with phenyl isothiocyanate pre-column derivatization, we successfully isolated imidazole peptides and their constituents. We detected Bal and 3-methylhistidine (3-Me-His) in mouse blood 1 h after the administration of opah-derived Bal. The concentrations of Bal and 3-Me-His significantly increased to 128.27 and 69.09 nmol/mL in plasma, respectively, but were undetectable in control and carnosine (Car)-administrated mice. In contrast, ß-alanine and histidine did not increase in mouse plasma 1 h after the administration of Car and opah-derived Bal. The present study is the first report on the absorption of food-derived Bal in mouse blood and serves as a pilot study for future clinical trials.

An Injectable Hybrid Gelatin Methacryloyl (GelMA)/Phenyl Isothiocyanate-Modified Gelatin (Gel-Phe) Bioadhesive for Oral/Dental Hemostasis Applications.

Biomaterials are widely used for effectively controlling bleeding in oral/dental surgical procedures. Here, gelatin methacryloyl (GelMA) was synthesized by grafting methacrylic anhydride on gelatin backbone, and phenyl isothiocyanate-modified gelatin (Gel-Phe) was synthesized by conjugating different gelatin/phenyl isothiocyanate molar ratios (G/P ratios) (i.e., 1:1, 1:5, 1:10, 1:15, 1:25, 1:50, 1:100, and 1:150) with gelatin polymer chains. Afterward, we combined GelMA and Gel-Phe as an injectable and photo-crosslinkable bioadhesive. This hybrid material system combines photo-crosslinking chemistry and supramolecular interactions for the design of bioadhesives exhibiting a highly porous structure, injectability, and regulable mechanical properties. By simply regulating the G/P ratio (1:1-1:15) and UV exposure times (15-60 s), it was possible to modulate the injectability and mechanical properties of the GelMA/Gel-Phe bioadhesive. Moreover, we demonstrated that the GelMA/Gel-Phe bioadhesive showed low cytotoxicity, a highly porous network, and the phenyl-isothiourea and amine residues on Gel-Phe and GelMA polymers with synergized hemostatic properties towards fast blood absorption and rapid clotting effect. An in vitro porcine skin bleeding and an in vitro dental bleeding model confirmed that the bioadhesive could be directly extruded into the bleeding site, rapidly photo-crosslinked, and reduced blood clotting time by 45%. Moreover, the in situ crosslinked bioadhesive could be easily removed from the bleeding site after clotting, avoiding secondary wound injury. Overall, this injectable GelMA/Gel-Phe bioadhesive stands as a promising hemostatic material in oral/dental surgical procedures.

Rapid analysis of phenyl isothiocyanate derivatives of amino acids present in Czech meads.

Amino acids (AAs) are minor compounds occurring in meads contributing to their final organoleptic properties. Determination of AAs profile and content can help to assess the mead authenticity, adulteration and thus its quality. This work deals with the optimization of rapid analysis of 21 AAs present in mead using reversed-phase high performance liquid chromatography with spectrophotometric detection after simple derivatization procedure with phenyl isothiocyanate agent without any sample pre-treatment. Optimized derivatization and separation conditions have been successfully applied to the quantification of AAs present in five Czech meads using the multiple point standard addition method. The total amino acid content was in the range of 134-828 mg/L. The content of proline was confirmed by Harmonised spectrophotometric method. Both chromatographic and spectrophotometric methods provided overlapping results in the range of 30-266 mg/L.

Mannose-anchored N,N,N-trimethyl chitosan nanoparticles for pulmonary administration of etofylline.

Drug delivery to lungs via pulmonary administration offers potential for the development of new drug delivery systems. Here we fabricated the etofylline (ETO) encapsulated mannose-anchored N,N,N-trimethyl chitosan nanoparticles (Mn-TMC NPs). The prominent characteristics like biocompatibility, controlled release, targeted delivery, high penetrability, enhanced physical stability, and scalability mark Mn-TMC NPs as a viable alternative to various nanoplatform technologies for effective drug delivery. Mannosylation of TMC NPs leads to the evolution of new drug delivery vehicle with gratifying characteristics, and potential benefits in efficient drug therapy. It is widely accepted that following pulmonary administration, the introduction of mannose to the surface of drug nanocarriers provide selective macrophage targeting via receptor-mediated endocytosis. The fabricated Mn-TMC NPs exhibited particle size of 223.3 nm, PDI 0.490, and ζ-potential -19.1 mV, drug-loading capacity 76.26 ± 1.2%, and encapsulation efficiency of 91.75 ± 0.88%. Sustained drug release, biodegradation studies, stability, safety, and aerodynamic behavior revealed the effectiveness of prepared nanoformulation for pulmonary administration. In addition, the in vivo pharmacokinetic studies in Wistar rat model revealed a significant improvement in therapeutic efficacy of ETO, illustrating mannosylation a promising approach for efficient therapy of airway diseases following pulmonary administration.

Isothiocyanates: An Overview of Their Antimicrobial Activity against Human Infections.

The use of plant-derived products as antimicrobial agents has been investigated in depth. Isothiocyanates (ITCs) are bioactive products resulting from enzymatic hydrolysis of glucosinolates (GLs), the most abundant secondary metabolites in the botanical order Brassicales. Although the antimicrobial activity of ITCs against foodborne and plant pathogens has been well documented, little is known about their antimicrobial properties against human pathogens. This review collects studies that focus on this topic. Particular focus will be put on ITCs' antimicrobial properties and their mechanism of action against human pathogens for which the current therapeutic solutions are deficient and therefore of prime importance for public health. Our purpose was the evaluation of the potential use of ITCs to replace or support the common antibiotics. Even though ITCs appear to be effective against the most important human pathogens, including bacteria with resistant phenotypes, the majority of the studies did not show comparable results and thus it is very difficult to compare the antimicrobial activity of the different ITCs. For this reason, a standard method should be used and further studies are needed.

Application of 3,5-bis-(trifluoromethyl)phenyl isothiocyanate for the determination of selected biogenic amines by LC-tandem mass spectrometry and 19F NMR.

3,5-Bis-(trifluoromethyl)phenyl isothiocyanate, was used as a convenient reagent for the derivatization of histamine, tyramine, tryptamine and 2-phenylethylamine, which eliminates the purification step. The obtained derivatives were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Additionally, the total amount of these amines was determined by 19F nuclear magnetic resonance analysis. The procedures were optimized and validated for linearity, limit of detection and quantification, intra- and inter-day precision and recovery resulting in good reproducibility and accuracy. The reagent was applied for determination of the above mentioned biogenic amines in beverages, and permitted an undemanding separation and determination of the derivatives. Moreover, it is a convenient reagent for analysis of the total amine content by quantitative 19F NMR.

A New Reactive 1,8-Naphthalimide Derivative for Highly Selective and Sensitive Detection of Hg2.

A 1,8-naphthalimide derivative with a reactive aliphatic hydroxyl was designed and synthesized as a fluorescent probe. Its structure was characterized by IR, 1H NMR, 13C NMR, LC-MS and HPLC. The probe showed high selectivity and sensitivity to Hg2+ over other metal ions such as Pb2+, Na+, K+, Cd2+, Cr3+, Zn2+, Cu2+, Ni2+, Ca2+, Fe3+, Fe2+, Co2+, Mn2+ and Mg2+ in MeCN/H2O (15/85, v/v). The increase in fluorescence intensity was linearly proportional to the concentration of Hg2+ in the range of 18-40 µM with a detection limit of 1.38 × 10-7 mol/L. The probe could work in a pH span of 4.3-9.0 and respond to Hg2+ quickly with strong anti-interference ability. Job's plot suggested a 1:2 complex of the probe and Hg2+.

Simultaneous determination of 14 amino acids in Pfaf fia by RP-HPLC with pre-column derivatization / 药学实践杂志

Objective To develop a HPLC method for determining 14 hydrolyzed amino acids in Pfaf fia .Methods The sample was derivatized with phenyl isothiocyanate (PITC) .Amino acids were separated on Waters XBridge Shield RP18 (4.6 mm × 250 mm ,5 μm) column at the flow rate of 0.8 ml/min ,detected at 254 nm .The column temperature was 25 ℃ . Results The response was linear for 14 amino acids with a correlation coefficient r>0 .9990 .The average recoveries (n=6) were 90 .2%-105 .1% .Amino acids derivative solution remained stable in 24 hours .Conclusion This well-established method is very reliable .It can be used as a quantitative determination method for 14 amino acids in Pfaf fia .

Determination and analysis of free amino acids in snake venom / 中国生化药物杂志

Objective To establish a method for simulataneous determination of 18 free amino acids in snake venom. Methods Preparation of free amino acid samples by membrane. HPLC analysis was performed after derivatization by using phenyl isothiocyanate (PITC) as a derivative reagent, samples were analyzed on Ultimate LP-C18 column with gradient elution column of 0.05 mol/L sodium acetate buffer and methanol-acetonitrile- water (40:40:20), and current speed was1.0 mL/min, and the column temperature was set at 35℃, and detection wavelength was 254nm. Results The 18 kinds of amino acids showed a good linearity with the correlation coefficients ≥0.99. The recovery rate was 74.59%~110.62%. Snake venom contained 17 kinds of amino acids, the total content of amino acids was 0.2%. Conclusion The method was accurate, reproducible and reliable, and can be used for the determination of amino acids in snake venom and related products.

Absolute configuration, stability, and interconversion of 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine valine adducts and their phenylthiohydantoin derivatives.

Pyrrolizidine alkaloid-containing plants are widespread in the world and probably the most common poisonous plants affecting livestock, wildlife, and humans. Pyrrolizidine alkaloids require metabolic activation to form dehydropyrrolizidine alkaloids that bind to cellular proteins and DNA leading to hepatotoxicity, genotoxicity, and tumorigenicity. At present, it is not clear how dehydropyrrolizidine alkaloids bind to cellular amino acids and proteins to induced toxicity. We previously reported that reaction of dehydromonocrotaline with valine generated four highly unstable 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived valine (DHP-valine) adducts that upon reaction with phenyl isothiocyanate (PITC) formed four DHP-valine-PITC adduct isomers. In this study, we report the absolute configuration and stability of DHP-valine and DHP-valine-PITC adducts, and the mechanism of interconversion between DHP-valine-PITC adducts.

Crystal structure of chlorido-(η(2)-phenyl iso-thio-cyanate-κ(2) C,S)-mer-tris-(tri-methyl-phosphane-κP)iridium(I).

The molecule of the title compound, [IrCl(C7H5NS)(C3H9P)3], is a distorted octa-hedral iridium complex with three PMe3 ligands arranged in a meridional geometry, a chloride ion cis to all three PMe3 groups and the phenyl iso-thio-cyanate ligand bonded in an η(2)-fashion through the C and S atoms. The C atom is trans to the chloride ion and the S atom is responsible for a significant deviation from an ideal octa-hedral geometry. The geometric parameters for the metal-complexing phenyl isothiocyanate group are compared with other metal-complexed phenyl iso-thio-cyanates, as well as with examples of uncomplexed aryl iso-thio-cyanates.

Pharmacological characterization of the vascular effects of aryl isothiocyanates: is hydrogen sulfide the real player?

Hydrogen sulfide (H2S) is an endogenous gasotransmitter, which mediates important physiological effects in the cardiovascular system. Accordingly, an impaired production of endogenous H2S contributes to the pathogenesis of important cardiovascular disorders, such as hypertension. Therefore, exogenous compounds, acting as H2S-releasing agents, are viewed as promising pharmacotherapeutic agents for cardiovascular diseases. Thus, this paper aimed at evaluating the H2S-releasing properties of some aryl isothiocyanate derivatives and their vascular effects. The release of H2S was determined by amperometry, spectrophotometry and gas/mass chromatography. Moreover, the vascular activity of selected isothiocyanates were tested in rat conductance (aorta) and coronary arteries. Since H2S has been recently reported to act as an activator of vascular Kv7 potassium channels, the possible membrane hyperpolarizing effects of isothiocyanates were tested on human vascular smooth muscle (VSM) cells by spectrofluorescent dyes. Among the tested compounds, phenyl isothiocyanate (PhNCS) and 4-carboxyphenyl isothiocyanate (PhNCS-COOH) exhibited slow-H2S-release, triggered by organic thiols such as L-cysteine. These compounds were endowed with vasorelaxing effects on conductance and coronary arteries. Moreover, these two isothiocyanates caused membrane hyperpolarization of VSM cells. The vascular effects of isothiocyanates were strongly abolished by the selective Kv7-blocker XE991. In conclusion, the isothiocyanate function can be viewed as a suitable slow H2S-releasing moiety, endowed with vasorelaxing and hypotensive effects, typical of this gasotransmitter. Thus, such a chemical moiety can be employed for the development of novel chemical tools for basic studies and promising cardiovascular drugs.

Content Determination of 18 Amino Acids in Compound Amino Acid Injection by HPLC with Pre-column PITC Derivatization / 世界科学技术-中医药现代化

An efficient and sensitive analytical method for the simultaneous content determination of 18 amino acids in compound amino acid injection was developed using high performance liquid chromatography (HPLC) with pre-column derivatization. Phenyl isothiocyanate (PITC) was used as derivatization reagent. The target compounds were separated on a Unitary-C18 column (250 mm í 4.6 mm, 5 μm) in gradient elution mode using sodium acetate and the mixture of acetonitrile, methanol and water as mobile phases. The detection wavelength was 254 nm. The derivatization reagent dosage, derivatization time, salt concentration, the pH and the column temperature of mobile phase were investigated. Finally, 18 amino acids were separated within 40 minutes. The method showed that the good linearity (r2 ≥ 0.997 7) was at a range from 9 μg·mL-1 to 1 021 μg·mL-1. The recoveries ranged from 92.6% to 110.7%. And the relative standard deviations (RSD) ranged from 0.01% to 5.68%. The limits of quantification (LOQ, S/N = 10) ranged from 0.02 μg·mL-1 to 13.41 μg·mL-1. This method, which was simple, sensitive and accurate, can be applied for the content determination of amino acids in compound amino acid injections.

Determination of 13 amino acids in Asini Corii Colla by RP-HPLC with precolumn derivatization / 中草药

Objective: To establish a RP-HPLC method for the simultaneous determination of 13 amino acids in Asini Corii Colla. Methods: Asini Corii Colla was hydrolyzed for 3 h at 120°C using 6 mol/L hydrochloric acid, and the amino acids were determined by RP-HPLC after being derived with phenyl isothiocyanate. HPLC was performed on an Eclipse AAA column (75 mm × 4.6 mm, 3.5 μm) with acetonitrile-110 mmol/L ammonium acetate solution (1:99) as mobile phase A and acetic acid-acetonitrile-water (0.05:80:20) as mobile phase B in the gradient mode at a flow rate of 0.6 mL/min. The column temperature was 42°C, and the detection wavelength was set at 254 nm. Results: The 13 amino acids were separated within 36 min with a good linearity (r > 0.9977) in the range of the test concentration. The average recoveries (n = 3) were 95.2%-104.4% and the RSD values were less than 5.0%. Conclusion: The method is simple, accurate, and repeatable, which could be available for the quality control of Asini Corii Colla. It may also serve as a good reference for the determination of amino acids in other pharmaceuticals.