scholarly journals The Synthesis of α-Aminophosphonates via Enantioselective Organocatalytic Reaction of 1-(N-Acylamino)alkylphosphonium Salts with Dimethyl Phosphite

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 405
Author(s):  
Alicja Walęcka-Kurczyk ◽  
Krzysztof Walczak ◽  
Anna Kuźnik ◽  
Sebastian Stecko ◽  
Agnieszka Październiok-Holewa
Keyword(s):  
Amino Acids ◽  
Biological Activities ◽  
Crop Protection ◽  
Asymmetric Induction ◽  
Flash Chromatography ◽  
Racemic Mixture ◽  
Phosphonium Salts ◽  
Dimethyl Phosphite ◽  
Aminophosphonic Acids ◽  
Subsequent Substitution

α-Aminophosphonic acids are phosphorus analogues of α-amino acids. Compounds of this type find numerous applications in medicine and crop protection due to their unique biological activities. A crucial factor in these activities is the configuration of the stereoisomers. Only a few methods of stereoselective transformation of α-amino acids into their phosphorus analogues are known so far and all of them are based on asymmetric induction, thus involving the use of a chiral substrate. In contrast, we have focused our efforts on the development of an effective method for this type of transformation using a racemic mixture of starting N-protected α-amino acids and a chiral catalyst. Herein, a simple and efficient stereoselective organocatalytic α-amidoalkylation of dimethyl phosphite by 1-(N-acylamino)alkyltriphenylphosphonium salts to enantiomerically enriched α-aminophosphonates is reported. Using 5 mol% of chiral quinine- or hydroquinine-derived quaternary ammonium salts provides final products in very good yields up to 98% and with up to 92% ee. The starting phosphonium salts were easily obtained from α-amino acid derivatives by decarboxylative methoxylation and subsequent substitution with triphenylphosphonium tetrafluoroborate. The appropriate self-disproportionation of enantiomers (SDE) test for selected α-aminophosphonate derivatives via achiral flash chromatography was performed to confirm the reliability of the enantioselectivity results that were obtained.

scholarly journals Enantioselective and Synergistic Herbicidal Activities of Common Amino Acids Against Amaranthus tricolor and Echinochloa crus-galli

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2071
Author(s):  
Nawasit Chotsaeng ◽  
Chamroon Laosinwattana ◽  
Patchanee Charoenying
Keyword(s):  
Amino Acids ◽  
Biological Activities ◽  
Racemic Mixture ◽  
Amaranthus Tricolor ◽  
Pigment Synthesis ◽  
Barnyard Grass ◽  
Chemical Structures ◽  
Natural Substances ◽  
Wide Range ◽  
Acid Herbicides

Amino acids have a wide range of biological activities, which usually rely on the stereoisomer presented. In this study, glycine and 21 common α-amino acids were investigated for their herbicidal property against Chinese amaranth (Amaranthus tricolor L.) and barnyard grass (Echinochloa crus-galli (L.) Beauv.). Both d- and l-isomers, as well as a racemic mixture, were tested and found that most compounds barely inhibited germination but moderately suppressed seedling growth. Various ratios of d:l-mixture were studied and synergy between enantiomers was found. For Chinese amaranth, the most toxic d:l-mixtures were at 3:7 (for glutamine), 8:2 (for methionine), and 5:5 (for tryptophan). For barnyard grass, rac-glutamine was more toxic than the pure forms; however, d-tryptophan exhibited greater activity than racemate and l-isomer, indicating the sign of enantioselective toxicity. The mode of action was unclear, but d-tryptophan caused bleaching of leaves, indicating pigment synthesis of the grass was inhibited. The results highlighted the enantioselective and synergistic toxicity of some amino acids, which relied upon plant species, chemical structures, and concentrations. Overall, our finding clarifies the effect of stereoisomers, and provides a chemical clue of amino acid herbicides, which may be useful in the development of herbicides from natural substances.

scholarly journals Changes in Amino Acid Profiles and Bioactive Compounds of Thai Silk Cocoons as Affected by Water Extraction

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2033
Author(s):  
Chuleeporn Bungthong ◽  
Sirithon Siriamornpun
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Biological Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Silk Protein ◽  
Extraction Time ◽  
Antioxidant Power ◽  
Silk Cocoon ◽  
Amino Acid Profiles

Silk proteins have many advantageous components including proteins and pigments. The proteins—sericin and fibroin—have been widely studied for medical applications due to their good physiochemical properties and biological activities. Various strains of cocoon display different compositions such as amino-acid profiles and levels of antioxidant activity. Therefore, the objectives of this study were to find a suitable silk protein extraction method to obtain products with chemical and biological properties suitable as functional foods in two strains of Bombyx mori silk cocoon (Nangsew strains; yellow cocoon) and Samia ricini silk cocoon (Eri strains; white cocoon) extracted by water at 100 °C for 2, 4, 6 and 8 h. The results showed that Nangsew strains extracted for 6 h contained the highest amounts of protein, amino acids, total phenolics (TPC) and total flavonoids (TFC), plus DPPH radical-scavenging activity, ABTS radical scavenging capacity, and ferric reducing antioxidant power (FRAP), anti-glycation, α-amylase and α-glucosidase inhibition. The longer extraction time produced higher concentrations of amino acids, contributing to sweet and umami tastes in both silk strains. It seemed that the bitterness decreased as the extraction time increased, resulting in improvements in the sweetness and umami of silk-protein extracts.

Nanosheet-Enhanced Asymmetric Induction of Chiral α-Amino Acids in Catalytic Aldol Reaction

2012 ◽  
Vol 18 (48) ◽  
pp. 15323-15329 ◽  
Author(s):  
Li-Wei Zhao ◽  
Hui-Min Shi ◽  
Jiu-Zhao Wang ◽  
Jing He
Keyword(s):  
Amino Acids ◽  
Aldol Reaction ◽  
Asymmetric Induction

scholarly journals Assessment and determination of lyoprotectant for survival of freeze-dried Lactobacillus rhamnosus

2016 ◽  
Vol 20 (1) ◽  
pp. 105-113
Author(s):  
Zongcheng Miao ◽  
Yang Zhao ◽  
Xiaoping Huo
Keyword(s):  
Amino Acids ◽  
Fractional Factorial Design ◽  
Biological Activities ◽  
Lactobacillus Rhamnosus ◽  
Fractional Factorial ◽  
Practical Application ◽  
Steepest Ascent ◽  
Freeze Dried ◽  
Viable Bacteria

Abstract Currently research of lactic acid bacteria focus primarily on the functional probiotics, which are major beneficial biota in the gastrointestinal tract, have been industrial manufactured. Probiotics confer health benefits on the host need adequate amounts. However, the absence of data makes it difficult to ensure the maintenance biological activities and population of probiotic. In this research, a fractional factorial design and steepest ascent experiment were used to analyze the influence of lyoprotectant as carbohydrates, prebiotics and amino acids on the survival of the probiotic Lactobacillus rhamnosus. The results indicated a maximum survival rate and population of viable bacteria of L. rhamnosus to be 55.84 % and 1.60 ×1011 CFU/g after freeze-dried by using a combination of 10 g/100mL Sucrose, 2.5 g/100mL Isomaltooligosaccharide, 12 g/100mL Hydroxyproline. To a large extent, the survival and viability were dependent on the cryoprotectant used and make probiotics more attractive from a practical application in industrial viewpoint.

New structural insights into anomeric carbohydrate recognition by frutalin: an α-d-galactose-binding lectin from breadfruit seeds

2019 ◽  
Vol 476 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Antonio Eufrásio Vieira Neto ◽  
Felipe Domingos de Sousa ◽  
Humberto D'Muniz Pereira ◽  
Frederico Bruno Mendes Batista Moreno ◽  
Marcos Roberto Lourenzoni ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biological Activities ◽  
3D Structure ◽  
Carbohydrate Binding ◽  
X Ray Crystallography ◽  
Multiple Binding Sites ◽  
Multiple Binding ◽  
New Perspective ◽  
Dynamics Simulations ◽  
Binding Lectin

Abstract Frutalin (FTL) is a multiple-binding lectin belonging to the jacalin-related lectin (JRL) family and derived from Artocarpus incisa (breadfruit) seeds. This lectin specifically recognizes and binds α-d-galactose. FTL has been successfully used in immunobiological research for the recognition of cancer-associated oligosaccharides. However, the molecular bases by which FTL promotes these specific activities remain poorly understood. Here, we report the whole 3D structure of FTL for the first time, as determined by X-ray crystallography. The obtained crystals diffracted to 1.81 Å (Apo-frutalin) and 1.65 Å (frutalin–d-Gal complex) of resolution. The lectin exhibits post-translational cleavage yielding an α- (133 amino acids) and β-chain (20 amino acids), presenting a homotetramer when in solution, with a typical JRL β-prism. The β-prism was composed of three 4-stranded β-sheets forming three antiparallel Greek key motifs. The carbohydrate-binding site (CBS) involved the N-terminus of the α-chain and was formed by four key residues: Gly25, Tyr146, Trp147 and Asp149. Together, these results were used in molecular dynamics simulations in aqueous solutions to shed light on the molecular basis of FTL-ligand binding. The simulations suggest that Thr-Ser-Ser-Asn (TSSN) peptide excision reduces the rigidity of the FTL CBS, increasing the number of interactions with ligands and resulting in multiple-binding sites and anomeric recognition of α-d-galactose sugar moieties. Our findings provide a new perspective to further elucidate the versatility of FTL in many biological activities.

Oxidative Degradation of Amino Acids and Aminophosphonic Acids by 2,2′-Bipyridine Complexes of Copper(II)

2014 ◽  
Vol 2014 (17) ◽  
pp. 2829-2838 ◽  
Author(s):  
József S. Pap ◽  
Nadia El Bakkali-Tahéri ◽  
Antoine Fadel ◽  
Szabina Góger ◽  
Dóra Bogáth ◽  
...  
Keyword(s):  
Amino Acids ◽  
Oxidative Degradation ◽  
Aminophosphonic Acids

scholarly journals A Theoretical Model to Study the Interaction Between Boronic Acids and Insulin

2020 ◽  
Author(s):  
Durgesh Kumar ◽  
Kamlesh Kumari ◽  
PRASHANT SINGH
Keyword(s):  
Amino Acids ◽  
Theoretical Model ◽  
Boronic Acid ◽  
Significant Interaction ◽  
Biological Activities ◽  
Boronic Acids ◽  
Biological Molecules ◽  
Computational Tools ◽  
Medical Expertise ◽  
Stabilizing Agents

Boronic acids are widely used in various applications in view of their ability to recognize and bind at specific sites of the biological molecules to mimic several processes. Therefore, this has attracted the researchers, academician and medical expertise to explore them. In the present work, the authors have designed a theoretical approach to study the interaction of boronic acid with insulin using computational tools. A library of boronic acids (114 compounds) are designed, optimized and interacted with insulin using computational tools i.e. iGEMDOCK. Further, their different biological activities and toxicity are determined. Results indicates the promising potential of the boronic acids on interaction with the insulin. Amongst, 114 molecules of boronic acids, 3-Benzyloxyphenylboronic acid (71) showed the best interaction with amino-acids of insulin and significant interaction was shown with the Glu21 and His5 residues. Further, these results were compared with the stabilizing agents and found to be more potent.

scholarly journals Enantioselective organocatalysis in the synthesis of biologically relevant compounds

2016 ◽  
Author(s):  
Lukasz Albrecht
Keyword(s):  
Organic Chemistry ◽  
Amino Acids ◽  
Organic Molecules ◽  
Asymmetric Induction ◽  
Chiral Catalyst ◽  
Biologically Relevant ◽  
Enantioselective Reactions ◽  
Asymmetric Organocatalysis ◽  
Biologically Relevant Molecules ◽  
Operational Simplicity

The development of methods for the preparation of biologically relevant compounds in an enantiomerically enriched form constitutes one of the most significant tasks in the contemporary organic chemistry. In particular, enantioselective reactions where prochiral substrates are converted into enantiomerically enriched products in the presence of chiral catalyst are of great importance. Recently, asymmetric organocatalysis, where simple organic molecules are used as catalysts of various enantiodifferentiating reactions, has become a highly useful synthetic tool enabling for the efficient asymmetric induction based on diverse activation modes. Herein, we report our studies on organocatalytic, enantioselective strategies for the synthesis of biologically relevant molecules such as: quaternary α-amino acids and their isoelectronic analogs α-aminophosphonates, benzo[1,5]oxazocines, α-methylidene-δ-lactones, α-alkylidene-ketones, furfural derivatives, and benzothiophenes. The devised approaches utilize readily available chiral organocatalysts to control stereo-chemical reaction outcomes. Operational simplicity, efficiency and high enantio- and diastereoselectivities are the main benefits of the developed strategies.

Lactoserum

2019 ◽  
pp. 432-456
Author(s):  
Charu Gupta ◽  
Consuelo Pacheco ◽  
Dhan Prakash
Keyword(s):  
Amino Acids ◽  
Nutritive Value ◽  
Animal Feed ◽  
Biological Activities ◽  
Tissue Growth ◽  
Growth Enhancement ◽  
Full Spectrum ◽  
Health Goals ◽  
Cheese Industry ◽  
Branched Chain

Lactoserum, a byproduct of cheese industry, is rich in nutrients, but it is discharged directly into the environment. It has many human applications that promise to be a complete nutraceutical for the future generations. It is of high nutritive value and its products can be used as functional ingredients in food and pharmaceutical applications and as nutrients in dietary and health foods. They contain full spectrum of amino acids including essential and branched-chain amino acids which are important in tissue growth and repair. The other biological activities of lactoserum are antibiotic, anti-cancer, anti-toxin, immune-enhancer, and prebiotic (growth enhancement of gut microflora such as bifidobacteria). Lactoserum can thus be used as nutraceutical in various products like infant formulas, food supplements, cheese spreads, sports bars, and beverages to meet a variety of health goals for people of all ages, including animal feed.

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