scholarly journals Synthesis, Spectral, andIn VitroAntibacterial Studies of Organosilicon(IV) Complexes with Schiff Bases Derived from Amino Acids

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Har Lal Singh ◽  
Jangbhadur Singh ◽  
A. Mukherjee
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Antimicrobial Activity ◽  
Schiff Bases ◽  
Spectroscopic Studies ◽  
Molar Conductance ◽  
Molar Ratio ◽  
Trigonal Bipyramidal ◽  
Antibacterial Evaluation

The present work stems from our interest in the synthesis, characterization, and antibacterial evaluation of organosilicon(IV) complexes of a class of amino-acid-based Schiff base which have been prepared by the interaction of ethoxytrimethylsilane with the Schiff bases (N OH) in 1 : 1 molar ratio. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including electronic IR and NMR (1H,13C, and29Si) spectroscopy. The analytical and spectral data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated forin vitroantimicrobial activity against bacteria (Bacillus cereus,Nocardiaspp.,E. aerogenes,Escherichia coli,Klebsiellaspp., andStaphylococcusspp.). The complexes were found to be more potent as compared to the ligands.

scholarly journals Hypercoordinated Organosilicon(IV) and Organotin(IV) Complexes: Syntheses, Spectral Studies, and Antimicrobial Activity In Vitro

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kiran Singh ◽  
Parvesh Puri ◽  
Yogender Kumar ◽  
Chetan Sharma
Keyword(s):  
Antimicrobial Activity ◽  
Schiff Bases ◽  
Structural Features ◽  
Antimicrobial Activities ◽  
Molar Conductance ◽  
Spectral Studies ◽  
Nmr Studies ◽  
Trigonal Bipyramidal ◽  
Elemental Analyses

This paper deals with the syntheses and structural features of some new diorganosilicon(IV) and diorganotin(IV) complexes having general formulae (CH3)2MCl(L1), (CH3)2MCl(L2), (CH3)2M(L1)2, and (CH3)2M(L2)2 with new Schiff bases (M = Si and Sn). The Schiff bases HL1 and HL2 have been derived from the condensation of 3-bromobenzaldehyde with 4-amino-3-ethyl-5-mercapto-1,2,4-triazole and 4-amino-5-mercapto-3-propyl-1,2,4-triazole, respectively. The compounds have been characterized by the elemental analyses, molar conductance, and spectral (UV, IR, 1H, 13C, 29Si, and 119Sn NMR) studies. The resulting complexes have been proposed to have trigonal bipyramidal and octahedral geometries. In vitro antimicrobial activities of the compounds have been carried out.

scholarly journals Biological and Spectral Studies of Newly Synthesized Triazole Schiff Bases and Their Si(IV), Sn(IV) Complexes

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Kiran Singh ◽  
Parvesh Puri ◽  
Yogender Kumar ◽  
Chetan Sharma ◽  
Kamal Rai Aneja
Keyword(s):  
Nmr Spectroscopy ◽  
Metal Complexes ◽  
Schiff Bases ◽  
Molar Conductance ◽  
Molar Ratio ◽  
Spectral Studies ◽  
Trigonal Bipyramidal ◽  
Elemental Analyses ◽  
Bacteria And Fungi

The Schiff bases HL1-3have been prepared by the reaction of 5-bromothiophene-2-carboxaldehyde with 4-amino-5-mercapto-3-methyl/propyl/isopropyl-s-triazole, respectively. Organosilicon(IV) and organotin(IV) complexes of formulae (CH3)2MCl(L1-3), (CH3)2M(L1-3)2were synthesized from the reaction of (CH3)2MCl2and the Schiff bases in 1 : 1 and 1 : 2 molar ratio, where and Sn. The synthesized Schiff bases and their metal complexes have been characterized with the aid of various physicochemical techniques like elemental analyses, molar conductance, UV, IR,1H,13C,29Si, and119Sn NMR spectroscopy. Based on these studies, the trigonal bipyramidal and octahedral geometries have been proposed for these complexes. The ligands and their metal complexes have been screenedin vitroagainst some bacteria and fungi.

scholarly journals Synthesis, Spectroscopic, Molecular Structure, and Antibacterial Studies of Dibutyltin(IV) Schiff Base Complexes Derived from Phenylalanine, Isoleucine, and Glycine

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Har Lal Singh ◽  
Jangbhadur Singh
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Schiff Bases ◽  
Molar Conductance ◽  
Schiff Base Complexes ◽  
Spectral Studies ◽  
E Coli ◽  
Elemental Analyses ◽  
In Vitro Antibacterial Activity

New series of organotin(IV) complexes and Schiff bases derived from amino acids have been designed and synthesized from condensation of1H-indole-2,3-dione, 5-chloro-1H-indole-2,3-dione, andα-amino acids (phenylalanine, isoleucine, and glycine). All compounds are characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (1H,13C, and119Sn NMR) spectral studies. The results suggest that Schiff bases behave as monobasic bidentate ligands and coordinate with dibutyltin(IV) in octahedral geometry according to the general formula [Bu2Sn(L)2]. Elemental analyses and NMR spectral data of the ligands with their dibutyltin(IV) complexes agree with their proposed distorted octahedral structures. Few representative compounds are tested for their in vitro antibacterial activity against Gram-positive (B. cereus,Staphylococcusspp.) and Gram-negative (E. coli,Klebsiellaspp.) bacteria. The results show that the dibutyltin complexes are more reactive with respect to their corresponding Schiff base ligands.

scholarly journals Spectral Studies and Bactericidal, Fungicidal, Insecticidal and Parasitological Activities of Organotin(IV) Complexes of Thio Schiff Bases Having no Donor Atoms

1995 ◽  
Vol 2 (6) ◽  
pp. 297-309 ◽  
Author(s):  
Mala Nath ◽  
Savita Goyal
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Schiff Bases ◽  
Thermal Studies ◽  
Far Infrared ◽  
Trichophyton Mentagrophytes ◽  
Spectral Studies ◽  
No Donor

Twelve new organotin(IV) complexes of the type RnSnLm [where n = 3, m = 1, R = CH3 or C6H5 ; n = 2, m = 2, R = C6H5 or C4H9 ; L = anion of Schiff bases derived from the condensation of 2-amino-5-(o -anisyl)-l,3,4-thiadiazole with salicylaldehyde (HL-1), 2- hydroxynaphthaldehyde (HL-2) and 2-hydroxyacetophenone (HL-3)] have been synthesized and characterized by elemental analysis, molar conductances, electronic, infrared, far-infrared, H1 NMR and S119n Mössbauer spectral studies. Thermal studies of two complexes, viz., Ph3Sn (L-1) and Ph2Sn(L-2)2 have been carried out in the temperature range 25-1000∘C using TG, DTG and DTA techniques. All these complexes decompose gradually with the formation of SnO2 as an end product. In vitro antimicrobial activity of the Schiff bases and their complexes has also been determined against Streptococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus Penicillin resistance (2500 units), Candida albicans, Cryptococcus neoformans, Sporotrichum schenckii, Trichophyton mentagrophytes and Aspergillus fumigatus. The Schiff bases (HL-1), (HL-2) and the organotin(IV) compounds have also been tested against various important herbicidal, fungicidal, insecticidal species and also for parasitological activity against freeliving nematode.

Diorganotin(IV) complexes of flexible N-protected amino acids and ketoximes: preparation and structure – antimicrobial activity relationship

2016 ◽  
Vol 94 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Arti Sharma ◽  
Asha Jain ◽  
Sanjiv Saxena
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Antimicrobial Activity ◽  
Spectral Data ◽  
Molar Ratio ◽  
Spectral Studies ◽  
Sodium Salts ◽  
Mass Spectral ◽  
Elemental Analyses

Diorganotin(IV) complexes of flexible N-protected amino acids and ketoximes having the compositions Me2Sn [[Formula: see text]CHRCOO][ON = C6H10] (where R = –CH2CH(CH3)2, –CH(CH3)C2H5,–CH2C6H5, –CH(CH3)2) and Me2Sn[[Formula: see text]CHRCOO][ON=CR′R″] (where R = –CH2CH(CH3)2, –CH(CH3)C2H5, –CH2C6H5, R′ = R″ = CH3; R = –CH(CH3)C2H5, –CH2C6H5, –CH(CH3)2, R′ = CH3, R″ = C6H5) were prepared by the reaction of dimethyltin(IV) dichloride with sodium salts of flexible N-protected amino acids and ketoximes in 1:1:1 molar ratio in refluxing dry benzene. The synthesized complexes were characterized by elemental analyses and IR, multinuclear NMR (1H, 13C, and 119Sn), and mass spectral studies. Plausible structures of these complexes have been suggested on the basis of molecular weight measurements and spectral data. 119Sn NMR spectral data indicate the presence of pentacoordinated tin centres in these complexes. Some of the synthesized complexes and their ligands were also screened for their in vitro antimicrobial activity.

Mechanisms involved in effects of antimicrobial peptides, bactenectins ChBac3.4, ChBac5, and mini-ChBac7.5Nb, on bacterial cells

2017 ◽  
pp. 43-50
Author(s):  
О.В. Шамова ◽  
М.С. Жаркова ◽  
П.М. Копейкин ◽  
Д.С. Орлов ◽  
Е.А. Корнева
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Innate Immunity ◽  
Infectious Diseases ◽  
Metabolic Activity ◽  
Capra Hircus ◽  
Bacterial Cells ◽  
Antibiotic Resistant ◽  
Resistant Strains

Антимикробные пептиды (АМП) системы врожденного иммунитета - соединения, играющие важную роль в патогенезе инфекционных заболеваний, так как обладают свойством инактивировать широкий спектр патогенных бактерий, обеспечивая противомикробную защиту живых организмов. В настоящее время АМП рассматриваются как потенциальные соединения-корректоры инфекционной патологии, вызываемой антибиотикорезистентными бактериями (АБР). Цель данной работы состояла в изученим механизмов антибактериального действия трех пептидов, принадлежащих к семейству бактенецинов - ChBac3.4, ChBac5 и mini-ChBac7.5Nb. Эти химически синтезированные пептиды являются аналогами природных пролин-богатых АМП, обнаруженных в лейкоцитах домашней козы Capra hircus и проявляющих высокую антимикробную активность, в том числе и в отношении грамотрицательных АБР. Методы. Минимальные ингибирующие и минимальные бактерицидные концентрации пептидов (МИК и МБК) определяли методом серийных разведений в жидкой питательной среде с последующим высевом на плотную питательную среду. Эффекты пептидов на проницаемость цитоплазматической мембраны бактерий для хромогенного маркера исследовали с использованием генетически модифицированного штамма Escherichia coli ML35p. Действие бактенецинов на метаболическую активность бактерий изучали с применением маркера резазурина. Результаты. Показано, что все исследованные пептиды проявляют высокую антимикробную активность в отношении Escherichia coli ML35p и антибиотикоустойчивых штаммов Escherichia coli ESBL и Acinetobacter baumannii in vitro, но их действие на бактериальные клетки разное. Использован комплекс методик, позволяющих наблюдать в режиме реального времени динамику действия бактенецинов в различных концентрациях (включая их МИК и МБК) на барьерную функцию цитоплазматической мембраны и на интенсивность метаболизма бактериальных клеток, что дало возможность выявить различия в характере воздействия бактенецинов, отличающихся по структуре молекулы, на исследуемые микроорганизмы. Установлено, что действие каждого из трех исследованных бактенецинов в бактерицидных концентрациях отличается по эффективности нарушения целостности бактериальных мембран и в скорости подавления метаболизма клеток. Заключение. Полученная информация дополнит существующие фундаментальные представления о механизмах действия пролин-богатых пептидов врожденного иммунитета, а также послужит основой для биотехнологических исследований, направленных на разработку на базе этих соединений новых антибиотических препаратов для коррекции инфекционных заболеваний, вызываемых АБР и являющимися причинами тяжелых внутрибольничных инфекций. Antimicrobial peptides (AMPs) of the innate immunity are compounds that play an important role in pathogenesis of infectious diseases due to their ability to inactivate a broad array of pathogenic bacteria, thereby providing anti-microbial host defense. AMPs are currently considered promising compounds for treatment of infectious diseases caused by antibiotic-resistant bacteria. The aim of this study was to investigate molecular mechanisms of the antibacterial action of three peptides from the bactenecin family, ChBac3.4, ChBac5, and mini-ChBac7.5Nb. These chemically synthesized peptides are analogues of natural proline-rich AMPs previously discovered by the authors of the present study in leukocytes of the domestic goat, Capra hircus. These peptides exhibit a high antimicrobial activity, in particular, against antibiotic-resistant gram-negative bacteria. Methods. Minimum inhibitory and minimum bactericidal concentrations of the peptides (MIC and MBC) were determined using the broth microdilution assay followed by subculturing on agar plates. Effects of the AMPs on bacterial cytoplasmic membrane permeability for a chromogenic marker were explored using a genetically modified strain, Escherichia coli ML35p. The effect of bactenecins on bacterial metabolic activity was studied using a resazurin marker. Results. All the studied peptides showed a high in vitro antimicrobial activity against Escherichia coli ML35p and antibiotic-resistant strains, Escherichia coli ESBL and Acinetobacter baumannii, but differed in features of their action on bacterial cells. The used combination of techniques allowed the real-time monitoring of effects of bactenecin at different concentrations (including their MIC and MBC) on the cell membrane barrier function and metabolic activity of bacteria. The differences in effects of these three structurally different bactenecins on the studied microorganisms implied that these peptides at bactericidal concentrations differed in their capability for disintegrating bacterial cell membranes and rate of inhibiting bacterial metabolism. Conclusion. The obtained information will supplement the existing basic concepts on mechanisms involved in effects of proline-rich peptides of the innate immunity. This information will also stimulate biotechnological research aimed at development of new antibiotics for treatment of infectious diseases, such as severe in-hospital infections, caused by antibiotic-resistant strains.

Extent of damage to amino acid availability of whey protein heated with sugar

1991 ◽  
Vol 58 (4) ◽  
pp. 431-441 ◽  
Author(s):  
Thérèse Desrosiers ◽  
Laurent Savoie
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Whey Protein ◽  
Significant Proportion ◽  
Protein Digestibility ◽  
Heating Time ◽  
Heat Treatments ◽  
Molar Ratio ◽  
Amino Acid Availability

SummaryThe effect of heat treatments, at various water activities (αw), on digestibility and on the availabilities of amino acids of whey protein samples in the presence of lactose was estimated by an in vitro digestion method with continuons dialysis. Four αw (0·3, 0·5, 0·7 and 0·97), three temperatures (75, 100 and 121 °C) and three heating periods (50, 500 and 5000 s) were selected. The initial lysine: lactose molar ratio was 1:1. Amino acid profiles showed that excessive heating of whey (121 °C, 5000 s) destroyed a significant proportion of cystine at all αw, lysine at αw 0·3, 0·5 and 0·7, and arginine at αw 0·5 and 0·7. At αw 0·3, 0·5 and 0·7, protein digestibility decreased (P < 0·05) as the temperature increased from 75 to 121 °C for a heating period of 5000 s, and as the heating time was prolonged from 500 to 5000 s at 121 °C. Excessive heating also decreased (P < 0·05) the availabilities of ail amino acids at αw 0·3, 0·5 and 0·7. The availabilities of lysine, proline, aspartic acid, glutamic acid, threonine, alanine, glycine and serine were particularly affected. Severe heating at αw 0·97 did not seem to favour the Maillard reaction, but the availabilities of cystine, tyrosine and arginine were decreased, probably as a result of structural modifications of the protein upon heating. Heating whey protein concentrates in the presence of lactose not only affected lysine, but also impaired enzymic liberation of other amino acids, according to the severity of heat treatments and αw.

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