scholarly journals The Very First Modification of Pleuromutilin and Lefamulin by Photoinitiated Radical Addition Reactions—Synthesis and Antibacterial Studies

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2028
Author(s):  
Son Thai Thai Le ◽  
Dávid Páll ◽  
Erzsébet Rőth ◽  
Tuyen Tran ◽  
Nóra Debreczeni ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Coupling Reaction ◽  
Addition Reactions ◽  
The Novel ◽  
Bacterial Strains ◽  
Multiresistant Pathogens ◽  
Induce Resistance ◽  
Derivatives Of

Pleuromutilin is a fungal diterpene natural product with antimicrobial properties, semisynthetic derivatives of which are used in veterinary and human medicine. The development of bacterial resistance to pleuromutilins is known to be very slow, which makes the tricyclic diterpene skeleton of pleuromutilin a very attractive starting structure for the development of new antibiotic derivatives that are unlikely to induce resistance. Here, we report the very first synthetic modifications of pleuromutilin and lefamulin at alkene position C19–C20, by two different photoinduced addition reactions, the radical thiol-ene coupling reaction, and the atom transfer radical additions (ATRAs) of perfluoroalkyl iodides. Pleuromutilin were modified with the addition of several alkyl- and aryl-thiols, thiol-containing amino acids and nucleoside and carbohydrate thiols, as well as perfluoroalkylated side chains. The antibacterial properties of the novel semisynthetic pleuromutilin derivatives were investigated on a panel of bacterial strains, including susceptible and multiresistant pathogens and normal flora members. We have identified some novel semisynthetic pleuromutilin and lefamulin derivatives with promising antimicrobial properties.

Antibacterial Potential of a Novel Peptide from the Consensus sequence of Dermaseptin Related Peptides Secreted by Agalychnis annae

2020 ◽  
Vol 21 ◽  
Author(s):  
Ya’u Sabo Ajingi ◽  
Auwal Muhammad ◽  
Pongsak Khunrae ◽  
Triwit Rattanarojpong ◽  
Kovit Pattanapanyasate ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Bacterial Resistance ◽  
Consensus Sequence ◽  
Membrane Damage ◽  
Antibacterial Properties ◽  
Peptide Sequence ◽  
The Novel ◽  
Bacterial Strains ◽  
Skin Secretions ◽  
Antibacterial Potential

Background: The consistently increasing reports of bacterial resistance and the reemergence of bacterial epidemics have inspired the health and scientific community to discover new molecules with antibacterial potential continuously. Frog-skin secretions constitute bioactive compounds essential for finding new biopharmaceuticals. The exact antibacterial characterization of dermaseptin related peptides derived from Agalychnis annae is limited. The resemblance in their conserved and functionally linked genomes indicates an unprecedented opportunity to obtain novel bioactive compounds. Objective: In this study, we derived a novel peptide sequence and determined its antibacterial potentials. Method: Consensus sequence strategy was used to design the novel and active antibacterial peptide named 'AGAAN' from skin secretions of Agalychnis annae. The In-vitro activities of the novel peptide against some bacterial strains were investigated. Time kill studies, DNA retardation, cytotoxicity, beta-galactosidase, and molecular computational studies were conducted. Results: AGAAN inhibited P. aeruginosa, E. faecalis, and S. typhimurium at 20 µM concentration. E. coli and S. aureus were inhibited at 25 µM, and lastly, B. subtilis at 50 µM. Kinetics of inactivation against exponential and stationary growing bacteria was found to be rapid within 1-5 hours of peptide exposure, depending on time and concentration. The peptide displayed weak hemolytic activity between 0.01%–7.31% at the antibacterial concentrations. AGAAN efficiently induced bacterial membrane damage with subsequent cell lysis. The peptide's DNA binding shows that it also targets intracellular DNA by retarding its movement. Our in-silico molecular docking analysis displayed a strong affinity to the bacterial cytoplasmic membrane. Conclusion: AGAAN exhibits potential antibacterial properties that could be used to combat bacterial resistance.

scholarly journals Alkaloid-Rich Crude Extracts, Fractions and Piperamide Alkaloids of Piper guineense Possess Promising Antibacterial Effects

Antibiotics ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 98 ◽  
Author(s):  
Eunice Mgbeahuruike ◽  
Pia Fyhrquist ◽  
Heikki Vuorela ◽  
Riitta Julkunen-Tiitto ◽  
Yvonne Holm
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Hot Water ◽  
Bacterial Strains ◽  
Inhibitory Effects ◽  
Piper Guineense ◽  
E Coli ◽  
Growth Inhibitory ◽  
Derivatives Of

Piper guineense is a food and medicinal plant commonly used to treat infectious diseases in West-African traditional medicine. In a bid to identify new antibacterial compounds due to bacterial resistance to antibiotics, twelve extracts of P. guineense fruits and leaves, obtained by sequential extraction, as well as the piperine and piperlongumine commercial compounds were evaluated for antibacterial activity against human pathogenic bacteria. HPLC-DAD and UHPLC/Q-TOF MS analysis were conducted to characterize and identify the compounds present in the extracts with promising antibacterial activity. The extracts, with the exception of the hot water decoctions and macerations, contained piperamide alkaloids as their main constituents. Piperine, dihydropiperine, piperylin, dihydropiperylin or piperlonguminine, dihydropiperlonguminine, wisanine, dihydrowisanine and derivatives of piperine and piperidine were identified in a hexane extract of the leaf. In addition, some new piperamide alkaloids were identified, such as a piperine and a piperidine alkaloid derivative and two unknown piperamide alkaloids. To the best of our knowledge, there are no piperamides reported in the literature with similar UVλ absorption maxima and masses. A piperamide alkaloid-rich hexane leaf extract recorded the lowest MIC of 19 µg/mL against Sarcina sp. and gave promising growth inhibitory effects against S. aureus and E. aerogenes as well, inhibiting the growth of both bacteria with a MIC of 78 µg/mL. Moreover, this is the first report of the antibacterial activity of P. guineense extracts against Sarcina sp. and E. aerogenes. Marked growth inhibition was also obtained for chloroform extracts of the leaves and fruits against P. aeruginosa with a MIC value of 78 µg/mL. Piperine and piperlongumine were active against E. aerogenes, S. aureus, E. coli, S. enterica, P. mirabilis and B. cereus with MIC values ranging from 39–1250 µg/mL. Notably, the water extracts, which were almost devoid of piperamide alkaloids, were not active against the bacterial strains. Our results demonstrate that P. guineense contains antibacterial alkaloids that could be relevant for the discovery of new natural antibiotics.

scholarly journals Sustained Release from Injectable Composite Gels Loaded with Silver Nanowires Designed to Combat Bacterial Resistance in Bone Regeneration Applications

Pharmaceutics ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 116 ◽  
Author(s):  
Arianna De Mori ◽  
Meena Hafidh ◽  
Natalia Mele ◽  
Rahmi Yusuf ◽  
Guido Cerri ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Composite Scaffold ◽  
Silver Nanowires ◽  
Gelation Time ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Bone Tissue Regeneration ◽  
Composite Gels ◽  
Prevention Of Infections

One-dimensional nanostructures, such as silver nanowires (AgNWs), have attracted considerable attention owing to their outstanding electrical, thermal and antimicrobial properties. However, their application in the prevention of infections linked to bone tissue regeneration intervention has not yet been explored. Here we report on the development of an innovative scaffold prepared from chitosan, composite hydroxyapatite and AgNWs (CS-HACS-AgNWs) having both bioactive and antibacterial properties. In vitro results highlighted the antibacterial potential of AgNWs against both gram-positive and gram-negative bacteria. The CS-HACS-AgNWs composite scaffold demonstrated suitable Ca/P deposition, improved gel strength, reduced gelation time, and sustained Ag+ release within therapeutic concentrations. Antibacterial studies showed that the composite formulation was capable of inhibiting bacterial growth in suspension, and able to completely prevent biofilm formation on the scaffold in the presence of resistant strains. The hydrogels were also shown to be biocompatible, allowing cell proliferation. In summary, the developed CS-HACS-AgNWs composite hydrogels demonstrated significant potential as a scaffold material to be employed in bone regenerative medicine, as they present enhanced mechanical strength combined with the ability to allow calcium salts deposition, while efficiently decreasing the risk of infections. The results presented justify further investigations into the potential clinical applications of these materials.

scholarly journals Synthesis of Copper Nanoparticles by Thermal Decomposition and Their Antimicrobial Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
R. Betancourt-Galindo ◽  
P. Y. Reyes-Rodriguez ◽  
B. A. Puente-Urbina ◽  
C. A. Avila-Orta ◽  
O. S. Rodríguez-Fernández ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Copper Nanoparticles ◽  
Copper Chloride ◽  
Metallic Copper ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Face Centered Cubic ◽  
Bacterial Strains ◽  
Tem Analysis

Copper nanoparticles were synthesized by thermal decomposition using copper chloride, sodium oleate, and phenyl ether as solvent agents. The formation of nanoparticles was evidenced by the X-ray diffraction and transmission electron microscopy. The peaks in the XRD pattern correspond to the standard values of the face centered cubic (fcc) structure of metallic copper and no peaks of other impurity crystalline phases were detected. TEM analysis showed spherical nanoparticles with sizes in the range of 4 to 18 nm. The antibacterial properties of copper nanoparticles were evaluatedin vitroagainst strains ofStaphylococcus aureusandPseudomonas aeruginosa. The antibacterial activity of copper nanoparticles synthesized by thermal decomposition showed significant inhibitory effect against these highly multidrug-resistant bacterial strains.

scholarly journals Synthesis and Antimicrobial Evaluation of New Series of 1,3,4-Oxadiazole Containing Cinnamic Acid Derivatives

2021 ◽  
Vol 8 (1) ◽  
pp. 11-16
Author(s):  
Yasin SarveAhrabi ◽  
Nakisa Zarrabi Ahrabi ◽  
Ali Souldozi
Keyword(s):  
Cinnamic Acid ◽  
Fungal Pathogens ◽  
Antibacterial Properties ◽  
New Drugs ◽  
Future Research ◽  
Bacterial Strains ◽  
Inhibitory Effects ◽  
Cinnamic Acid Derivatives ◽  
Minimum Fungicidal Concentration ◽  
Derivatives Of

Background: New drugs must be designed and synthesized for combating resistant pathogens. In this study, antibacterial and antifungal activities of 4 new derivatives of 1,3,4-oxadiazole were assessed against 8 bacterial and 2 fungal pathogens. Methods: To this end, the cinnamic acid derivatives were dissolved in acetonitrile solvent and N-iso-ciano-imino-triphenyl-phosphorane was added to the above-mentioned solution, followed by applying Petroleum ether and Ethyl acetate as solvent and base. Then, antimicrobial susceptibility tests were used to determine inhibition zone diameter, minimum inhibitory concentration, the minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) values. Results: The chemical structure of all compounds was characterized with infrared spectra, 1H-NMR, and 13C-NMR. A variety of inhibitory effects were observed by the synthesized compounds. Methoxyphenyl derivative (3c) affected bacterial strains, especially Streptococcus mutans. Other compounds also had antibacterial properties. Additionally, compound 3c showed the greatest effect on fungal samples, especially Aspergillus flavus. Conclusions: In general, our new derivatives of 1,3,4-oxadiazole are able to destroy Gram-positive bacteria. In addition, developing new derivatives of 1,3,4-oxadiazole in future research can improve therapeutic properties. It seems that with the addition of other functional groups and increasing the destructive power of compounds, inhibitory effects on fungal samples can also be observed.

scholarly journals Synthesis of Some Quinoxaline Sulfonamides as a Potential Antibacterial Agent

2021 ◽  
pp. 116-132
Author(s):  
Festus O. Taiwo ◽  
Craig A. Obafemi ◽  
David A. Akinpelu A. Akinpelu
Keyword(s):  
Antibacterial Activity ◽  
Broad Spectrum ◽  
Antibacterial Agent ◽  
Antibacterial Property ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Pharmacological Properties ◽  
Antimicrobial Compounds ◽  
Bacterial Strains ◽  
Bactericidal Effects

Aims: This studies aims at the synthesis of new heterocyclic systems and study its biological and pharmacological properties. Objective: This study was designed to synthesized some quinoxaline-2,3-dione with sulfonamide moiety, characterize the synthesized compounds, and study the antimicrobial properties of the synthesized compounds on some bacterial strains. Materials and Methods: Six quinoxaline-6-sulfonohydrazone derivatives were synthesized by reacting quinoxaline-6-sulfonohydrazine with some substituted benzaldehydes and ketones. The compounds were tested for their potential antibacterial properties. Results: All the test compounds possessed promising antibacterial property against a panel of bacterial strains used for this study. The MIC values exhibited by these compounds ranged between 0.0313 and 0.250 mg/mL. Among the compounds tested, compound 2 showed appreciable antibacterial activity. Discussion and Conclusion: The study concluded that all the compounds exhibited appreciable bactericidal effects towards all the bacterial strains, particularly, compound 2 This is an indication that such compounds possessing broad spectrum activities will be useful in formulating antimicrobial compounds which could be used to treat infections caused by pathogens that are now developing resistance against the available antibiotics.

scholarly journals Sustained Release from Injectable Composite Gels Loaded with Silver Nanowires Designed to Combat Bacterial Resistance in Bone Regeneration Applications

2019 ◽  
Author(s):  
Arianna De Mori ◽  
Meena Hafidh ◽  
Natalia Mele ◽  
Rahmi Yusuf ◽  
Guido Cerri ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Composite Scaffold ◽  
Silver Nanowires ◽  
Gelation Time ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Bone Tissue Regeneration ◽  
Composite Gels ◽  
Prevention Of Infections

One-dimensional nanostructures such as silver nanowires (AgNWs) have attracted considerable attention owing to their outstanding electrical, thermal and antimicrobial properties; however, their application in the prevention of infections linked to bone tissue regeneration interventions has not yet been explored. Here we report on the development of an innovative scaffold prepared from chitosan, composite hydroxyapatite and AgNWs (CS-HACS-AgNWs) having both bioactive and antibacterial properties. In vitro results highlighted the antibacterial potential of AgNWs against both gram-positive and gram-negative bacteria. The CS-HACS-AgNWs composite scaffold demonstrated suitable Ca/P deposition, improved gel strength, reduced gelation time, and sustained Ag+ release within therapeutic concentrations. Antibacterial studies showed that the composite formulation was capable of inhibiting bacterial growth in suspension and of completely preventing biofilm formation on the scaffold in the presence of resistant strains. The hydrogels were also shown to be biocompatible, allowing cell proliferation. In summary, the developed CS-HACS-AgNWs composite hydrogels demonstrated significant potential as a scaffold material to be employed in bone regenerative medicine, as it presents enhanced mechanical strength combined with the ability to allow calcium salts deposition, while efficiently decreasing the risk of infections. The results presented justify further investigations into potential clinical applications of these materials.

scholarly journals Enhancement of Antibiotic Activity by 1,8-Naphthyridine Derivatives against Multi-Resistant Bacterial Strains

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7400
Author(s):  
José B. de Araújo-Neto ◽  
Maria M. C. da Silva ◽  
Cícera D. de M. Oliveira-Tintino ◽  
Iêda M. Begnini ◽  
Ricardo A. Rebelo ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Antibiotic Activity ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Fluoroquinolone Antibiotics ◽  
Broth Microdilution Method ◽  
Resistant Strains

The search for new antibacterial agents has become urgent due to the exponential growth of bacterial resistance to antibiotics. Nitrogen-containing heterocycles such as 1,8-naphthyridine derivatives have been shown to have excellent antimicrobial properties. Therefore, the purpose of this study was to evaluate the antibacterial and antibiotic-modulating activities of 1,8-naphthyridine derivatives against multi-resistant bacterial strains. The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of the following compounds: 7-acetamido-1,8-naphthyridin-4(1H)-one and 3-trifluoromethyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide. The antibiotic-modulating activity was analyzed using subinhibitory concentrations (MIC/8) of these compounds in combination with norfloxacin, ofloxacin, and lomefloxacin. Multi-resistant strains of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were used in both tests. Although the compounds had no direct antibacterial activity (MIC ≥ 1.024 µg/mL), they could decrease the MIC of these fluoroquinolones, indicating synergism was obtained from the association of the compounds. These results suggest the existence of a structure–activity relationship in this group of compounds with regard to the modulation of antibiotic activity. Therefore, we conclude that 1,8-naphthyridine derivatives potentiate the activity of fluoroquinolone antibiotics against multi-resistant bacterial strains, and thereby interesting candidates for the development of drugs against bacterial infections caused by multidrug resistant strains.

scholarly journals Gram-scale synthesis of splat-shaped Ag–TiO2 nanocomposites for enhanced antimicrobial properties

2020 ◽  
Vol 11 ◽  
pp. 1119-1125
Author(s):  
Mohammad Jaber ◽  
Asim Mushtaq ◽  
Kebiao Zhang ◽  
Jindan Wu ◽  
Dandan Luo ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Gram Negative ◽  
E Coli ◽  
Contagious Diseases ◽  
Good Biocompatibility

The control over contagious diseases caused by pathogenic organisms has become a serious health issue. The extensive usage of antibiotics has led to the development of multidrug-resistant bacterial strains. In this regard, metal-oxide-based antibacterial nanomaterials have received potential research interest due to the efficient prevention of microorganism growth. In this study, splat-shaped Ag–TiO2 nanocomposites (NCs) were synthesized on the gram scale and the enhanced antibacterial properties of TiO2 in the presence of silver were examined. The formation of Ag–TiO2 NCs was analyzed through various characterization techniques. The cell viability experimental results demonstrated that the Ag–TiO2 NCs have good biocompatibility. The antibacterial activity of the prepared Ag–TiO2 NCs was tested against the Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacterial strains. The Ag–TiO2 NCs exhibited promising and superior antibacterial properties compared to TiO2 nanospheres as confirmed by the bacterial growth and inhibition zone. The improvement in the antibacterial activity was attributed to the synergistic effect of the hybrid nature of TiO2 nanoparticles in the presence of Ag.

scholarly journals Antioxidant, Antibacterial, and Cytotoxic Activities of the EthanolicOriganum vulgareExtract and Its Major Constituents

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
John Coccimiglio ◽  
Misagh Alipour ◽  
Zi-Hua Jiang ◽  
Christine Gottardo ◽  
Zacharias Suntres
Keyword(s):  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
A549 Cells ◽  
Antibacterial Activities ◽  
Major Constituent ◽  
Cytotoxic Activities ◽  
Bacterial Strains ◽  
Spectroscopy Analysis ◽  
Perennial Shrub ◽  
Gas Chromatography Mass Spectroscopy

Oregano is a perennial shrub that grows in the mountains of the Mediterranean and Euro/Irano-Siberian regions. This study was conducted to identify the major constituents of the ethanolicOriganum vulgareextract and examine the cytotoxic, antioxidant, and antibacterial properties of the extract but more importantly the contribution of its specific major constituent(s) or their combination to the overall extract biological activity. Gas chromatography/mass spectroscopy analysis showed that the extract contained monoterpene hydrocarbons and phenolic compounds, the major ones being carvacrol and thymol and to a lesser extent p-cymene, 1-octacosanol, creosol, and phytol. A549 epithelial cells challenged with the extract showed a concentration-dependent increase in cytotoxicity. A combination of thymol and carvacrol at equimolar concentrations to those present in the extract was less cytotoxic. The A549 cells pretreated with nonlethal extract concentrations protected against hydrogen-peroxide-induced cytotoxicity, an antioxidant effect more effective than the combination of equimolar concentrations of thymol/carvacrol. Inclusion of p-cymene and/or 1-octacosanol did not alter the synergistic antioxidant effects of the carvacrol/thymol mixture. The extract also exhibited antimicrobial properties against Gram-positive and Gram-negative bacterial strains including clinical isolates. In conclusion, the oregano extract has cytotoxic, antioxidant, and antibacterial activities mostly attributed to carvacrol and thymol.

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