scholarly journals Vitamin imposters: Hijacking the biosynthesis of coenzyme A for antimicrobial drug development

2015 ◽  
Vol 37 (1) ◽  
pp. 19-23
Author(s):  
Marianne de Villiers ◽  
Erick Strauss
Keyword(s):  
Biosynthetic Pathway ◽  
Antimicrobial Agents ◽  
Coenzyme A ◽  
Mechanisms Of Action ◽  
Clinical Use ◽  
Bacterial Strains ◽  
Dna And Rna ◽  
Drawing Board ◽  
To Come ◽  
Made In

Humankind's struggle to find cures for infectious diseases is as old as humanity itself. During the last century, we have probably made the greatest advance in our battle against these diseases: the discovery of antibiotics. Importantly, the first antimicrobial agents introduced for clinical use in 1937, the sulfonamide drugs, act by hijacking the disease-causing organism's biosynthetic pathway for making folic acid, a vitamin that is required in the synthesis of DNA and RNA. Since then, many other antibiotics with diverse mechanisms of action have been discovered, and, by the early 1960s, it seemed as if any infection could be treated successfully with a course of antibiotics. However, since the first introduction of these drugs, we have also started to suffer our greatest defeat: bacterial strains that show resistance against nearly every antibiotic were often isolated within a few years of their first clinical use. We have been forced back to the drawing board to come up with new antimicrobials, and this has led us to revisit the antimetabolite inhibition strategy used by the sulfonamide drugs. This article discusses the recent advances that have made in discovering compounds that interfere with the biosynthesis of the essential metabolic cofactor coenzyme A (CoA) from pantothenate (vitamin B5).

The Cephalosporin Antibiotics

1994 ◽  
Vol 15 (2) ◽  
pp. 54-62
Author(s):  
Toni Darville ◽  
Terry Yamauchi
Keyword(s):  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
The United States ◽  
Mechanisms Of Action ◽  
Clinical Use ◽  
Hospital Expenditures ◽  
Lactam Ring ◽  
Cephalosporin Antibiotics ◽  
Thiazolidine Ring ◽  
Antibacterial Spectrum

Introduction The first cephalosporin released for clinical use was cephalothin in 1964. Since that time, more than 20 cephalosporin antibiotics have been introduced. These are the most commonly prescribed antibiotics in the United States and account for the largest share of hospital expenditures. To determine which agent to use for an infection in a particular patient involves weighing competing claims of improved antibacterial spectrum, side effects, pharmacokinetics, and cost. This review will address these issues, as well as the basic mechanisms of action of the cephalosporins and their mechanisms of bacterial resistance. In addition, instances in which cephalosporins serve as appropriate alternatives or in which they offer distinct advantages over previously available antimicrobial agents will be described. Chemistry and Mechanism of Action Cephalosporins resemble penicillins (Fig.1) in that they have a β-lactam structure, but the five-member thiazolidine ring characteristic of the penicillins is replaced by a six-member dihydrothiazine ring (Fig. 2). The dihydrothiazine ring of the cephalosporins provides the molecule with the ability to resist bacterial enzymes; the antibacterial activity emanates from the β-lactam ring shared by penicillins and cephalosporins. Modifications at position 7 of the cephalosporin nucleus generally affect the antibacterial spectrum, and substitutions at position 3 of the dihydrothiazine ring alter the pharmacokinetics and metabolic parameters of the drug.

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Analysis ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Biological Evaluation ◽  
Fungal Strain ◽  
Bacterial Strains ◽  
Standard Drug ◽  
Gram Negative ◽  
E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

Preliminary in Vitro Investigations on The Inhibitory Activity of The Original Dietary Supplement Oxidal® on Pathogenic Bacterial Strains

2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov
Keyword(s):  
Dietary Supplement ◽  
Broad Spectrum ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Clinical Effectiveness ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Microbial Strains

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.

STUDIES ON SOME BACTERIAL DISEASES IN OREOCHROMIS NILOTICUS WITH SPECIAL REFERENCES TO TREATMENT

2018 ◽  
pp. 39-47
Author(s):  
Viola Zaki ◽  
Ahmed EL-gamal ◽  
Yasmin Reyad
Keyword(s):  
Oreochromis Niloticus ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Histopathological Examination ◽  
Klebsiella Oxytoca ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Tissue Samples ◽  
Hydropic Degeneration ◽  
Total Prevalence

he present research carried out to study the common bacterial infections in Oreochromis niloticus (Nile tilapia) in Manzala area at Dakahlia governorate and possible antimicrobial agents used for treatment. A total number of 400 fish were randomly collected from Manzala private farms at Dakahlia governorate and subjected to the clinical, bacteriological and histopathological examination. The highest prevalence of bacterial isolates during the whole period of examination of naturally infected O.niloticus was recorded for A.hydrophila (22.66%), followed by V.alginolyticus (19.01%), V.parahemolyticus (13.80%), Streptococcus spp. (12.24%), A.caviae (11.72%), V.cholera (10.16%), A.salmonicida (7.55%), while the lowest prevalence was recorded for Klebsiella oxytoca (2.86%). The seasonal highest total prevalence of bacterial isolates from examined naturally infected O. niloticus was recorded in spring (30.21%), followed by autumn (28.39%), then summer (22.40%) and the lowest prevalence was recorded in winter (19.01%). Histopathological findings of the tissue samples which collected from different organs of naturally infected O.niloticus revealed that spleen show marked hemosiderosis and sever hemorrhage, gills showsever congestion of lamellar capillaries with marked aneurysm, necrosis and hemorrhage of lamellar epithelium and liver show sever hydropic degeneration and necrosis of hepatocytes, Ciprofloxacin was the most effective antibiotic against all isolated bacterial strains

scholarly journals Silver (I) N-Heterocyclic Carbene Complexes: A Winning and Broad Spectrum of Antimicrobial Properties

2021 ◽  
Vol 22 (5) ◽  
pp. 2497
Author(s):  
Filippo Prencipe ◽  
Anna Zanfardino ◽  
Michela Di Napoli ◽  
Filomena Rossi ◽  
Stefano D’Errico ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Resistance Mechanisms ◽  
Heterocyclic Carbenes ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Development Of Resistance ◽  
Starting Point ◽  
Catalytic Chemistry

The evolution of antibacterial resistance has arisen as the main downside in fighting bacterial infections pushing researchers to develop novel, more potent and multimodal alternative drugs.Silver and its complexes have long been used as antimicrobial agents in medicine due to the lack of silver resistance and the effectiveness at low concentration as well as to their low toxicities compared to the most commonly used antibiotics. N-Heterocyclic Carbenes (NHCs) have been extensively employed to coordinate transition metals mainly for catalytic chemistry. However, more recently, NHC ligands have been applied as carrier molecules for metals in anticancer applications. In the present study we selected from literature two NHC-carbene based on acridinescaffoldand detailed nonclassicalpyrazole derived mono NHC-Ag neutral and bis NHC-Ag cationic complexes. Their inhibitor effect on bacterial strains Gram-negative and positivewas evaluated. Imidazolium NHC silver complex containing the acridine chromophore showed effectiveness at extremely low MIC values. Although pyrazole NHC silver complexes are less active than the acridine NHC-silver, they represent the first example of this class of compounds with antimicrobial properties. Moreover all complexesare not toxic and they show not significant activity againstmammalian cells (Hek lines) after 4 and 24 h. Based on our experimental evidence, we are confident that this promising class of complexes could represent a valuable starting point for developing candidates for the treatment of bacterial infections, delivering great effectiveness and avoiding the development of resistance mechanisms.

scholarly journals Cystathionine β-Lyase Is Important for Virulence of Salmonella enterica Serovar Typhimurium

2004 ◽  
Vol 72 (6) ◽  
pp. 3310-3314 ◽  
Author(s):  
Linda J. Ejim ◽  
Vanessa M. D'Costa ◽  
Nadine H. Elowe ◽  
J. Concepción Loredo-Osti ◽  
Danielle Malo ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biosynthetic Pathway ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Systemic Infection ◽  
Bacterial Virulence ◽  
Methionine Biosynthesis ◽  
Insertional Inactivation ◽  
Serovar Typhimurium

ABSTRACT The biosynthesis of methionine in bacteria requires the mobilization of sulfur from Cys by the formation and degradation of cystathionine. Cystathionine β-lyase, encoded by metC in bacteria and STR3 in Schizosaccharomyces pombe, catalyzes the breakdown of cystathionine to homocysteine, the penultimate step in methionine biosynthesis. This enzyme has been suggested to be the target for pyridinamine antimicrobial agents. We have demonstrated, by using purified enzymes from bacteria and yeast, that cystathionine β-lyase is not the likely target of these agents. Nonetheless, an insertional inactivation of metC in Salmonella enterica serovar Typhimurium resulted in the attenuation of virulence in a mouse model of systemic infection. This result confirms a previous chemical validation of the Met biosynthetic pathway as a target for the development of antibacterial agents and demonstrates that cystathionine β-lyase is important for bacterial virulence.

Prospects for immunomodulatory therapy of bronchial asthma

1998 ◽  
Vol 79 (5) ◽  
pp. 388-391
Author(s):  
G. V. Cherepnev ◽  
Y. D. Slabnov ◽  
I. E. Zimakova
Keyword(s):  
Bronchial Asthma ◽  
Russian Federation ◽  
Mechanisms Of Action ◽  
Immunomodulatory Therapy ◽  
Immune Homeostasis ◽  
Clinical Use ◽  
Immunological Reactivity ◽  
The Past ◽  
The Russian Federation ◽  
Pharmacological Correction

The relevance of pharmacological correction of immunological reactivity is obvious: many socially significant diseases are accompanied by an imbalance in immune homeostasis. In the past few years, a number of reviews on the classification and mechanisms of action of immunotropic drugs approved for clinical use in the Russian Federation have been published in the domestic press.

scholarly journals DPPH-Scavenging and Antimicrobial Activities of Asteraceae Medicinal Plants on Uropathogenic Bacteria

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Phan-Canh Trinh ◽  
Le-Thi-Thanh Thao ◽  
Hoang-Tran-Viet Ha ◽  
TuAnh Nguyen
Keyword(s):  
Antimicrobial Agents ◽  
Natural Antioxidants ◽  
Ethyl Acetate Fraction ◽  
Antimicrobial Activities ◽  
Chrysanthemum Morifolium ◽  
Bacterial Strains ◽  
Ageratum Conyzoides ◽  
Potent Effect ◽  
E Coli ◽  
Dpph Scavenging

Asteraceae species were widely applied in traditional medicines in Asian countries as sources of natural antioxidants and antimicrobial agents. This study aimed to evaluate DPPH-scavenging capacities and antimicrobial activities of nine Asteraceae species collected from Southern Vietnam. Antioxidant and antimicrobial activities were determined by standard protocols. Essential oils from Ageratum conyzoides, Helianthus annuus, and Artemisia vulgaris indicated significant inhibitory effects on Staphylococcus aureus and Candida spp. Crude extracts and fractions from Taraxacum officinale, Chrysanthemum morifolium, A. conyzoides, and Tagetes erecta showed inhibitory ability on at least one testing bacterial strains including S. aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In a study on clinical isolates, ethyl acetate fraction from A. conyzoides flower displayed the most potent effect on uropathogenic E. coli and K. pneumoniae with MIC at 1.25–10 mg/ml and 5–12.5 mg/ml, respectively. DPPH-scavenging assay indicated that T. erecta extract had the lowest IC50 (17.280 μg/ml) and is 2.4 times higher than vitamin C (7.321 μg/ml). This study revealed that A. conyzoides has good potential against uropathogenic E. coli and K. pneumoniae, and therefore could be applied for prophylactic treatment of urinary infection.

scholarly journals Microwave Assisted Synthesis and Antimicrobial Evaluation of Schiff Bases of Indole-3-aldehyde

2011 ◽  
Vol 8 (1) ◽  
pp. 305-311 ◽  
Author(s):  
Priyanka Kamaria ◽  
N. Kawathekar ◽  
Prerna Chaturvedi
Keyword(s):  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Microwave Assisted Synthesis ◽  
Bacterial Strains ◽  
Mass Spectral Analysis ◽  
Gram Positive ◽  
Gram Negative ◽  
Mass Spectral ◽  
Microwave Assisted ◽  
Antimicrobial Evaluation

In order to develop new antimicrobial agents, a series of Schiff bases of indole-3-aldehyde were synthesized by microwave assisted synthesis by takingDMFas solvent and evaluated for their antimicrobial activity. All the synthesized compounds were characterized byIR,1HNMRand mass spectral analysis. All compounds were tested against five gram positive and five gram negative bacterial strains and one fungal strain. All compounds exhibited better activity against gram positive strains than against gram negative strains and the compounds were found more active againstS.aureusandB.subtilis.

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