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14 pages, 2346 KiB

Open AccessArticle

Design, Synthesis, and Antimicrobial Activity Evaluation of Ciprofloxacin—Indole Hybrids

by Mingxia Song, Yi Hua, Yuxin Liu, Xunli Xiao, Haihong Yu and Xianqing Deng

Molecules 2023, 28(17), 6325; https://doi.org/10.3390/molecules28176325 - 29 Aug 2023

Cited by 1 | Viewed by 915

With the overuse and misuse of antimicrobial drugs, antibacterial resistance is becoming a critical global health problem. New antibacterial agents are effective measures for overcoming the crisis of drug resistance. In this paper, a novel set of ciprofloxacin-indole/acetophenone hybrids was designed, synthesized, and [...] Read more.

With the overuse and misuse of antimicrobial drugs, antibacterial resistance is becoming a critical global health problem. New antibacterial agents are effective measures for overcoming the crisis of drug resistance. In this paper, a novel set of ciprofloxacin-indole/acetophenone hybrids was designed, synthesized, and structurally elucidated with the help of NMR and high-resolution mass spectrometry. The in vitro antibacterial activities of these hybrids against gram-positive and gram-negative pathogens, including four multidrug-resistant clinical isolates, were evaluated and compared with those of the parent drug ciprofloxacin (CIP). All the target compounds (MIC = 0.0625–32 μg/mL) exhibited excellent inhibitory activity against the strains tested. Among them, 3a (MIC = 0.25–8 μg/mL) showed comparable or slightly less potent activity than CIP. The most active hybrid, 8b (MIC = 0.0626–1 μg/mL), showed equal or higher activity than CIP. Moreover, compound 8b showed superior bactericidal capability to CIP, with undetectably low resistance frequencies. Furthermore, molecular docking studies conducted showed that 8b and CIP had a similar binding mode to DNA gyrase (Staphylocouccus aureus). Thus, hybrids 3a and 8b could act as a platform for further investigations. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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14 pages, 1402 KiB

Open AccessArticle

Synthesis and Antimicrobial Activity of New Mannich Bases with Piperazine Moiety

by Sara Janowska, Sylwia Andrzejczuk, Piotr Gawryś and Monika Wujec

Molecules 2023, 28(14), 5562; https://doi.org/10.3390/molecules28145562 - 21 Jul 2023

Cited by 1 | Viewed by 2019

Abstract

A series of novel Mannich bases were designed, synthesized, and screened for their antimicrobial activity. The target compounds were synthesized from 4-(3-chlorophenyl)-5-(3-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione and different piperazine derivatives. The structures of the products were confirmed by ¹H and ¹³C NMR and [...] Read more.

A series of novel Mannich bases were designed, synthesized, and screened for their antimicrobial activity. The target compounds were synthesized from 4-(3-chlorophenyl)-5-(3-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione and different piperazine derivatives. The structures of the products were confirmed by ¹H and ¹³C NMR and elemental analysis. The activity of piperazine derivatives against bacteria (Gram-positive: Staphylococcus epidermidis, Staphylococcus aureus, Micrococcus luteus, Bacillus cereus, and Bacillus subtilis; Gram-negative: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Proteus mirabilis) and yeasts (Candida glabrata, Candida krusei, and Candida parapsilosis) was determined by the minimum inhibitory concentration and minimum bactericidal concentration values. Significant activity was observed against Gram-positive bacteria, mainly staphylococci (PG7–PG8) and bacteria of the genes of Micrococcus and Bacillus (PG1-3), as well as selected strains of Gram-negative bacteria, including bacteria of the Enterobacteriaceae family (PG7), while all tested compounds showed high fungistatic activity against Candida spp. yeasts, especially C. parapsilosis, with MICs ranging from 0.49 µg/mL (PG7) to 0.98 µg/mL (PG8) and 62.5 µg/mL (PG1-3). In conclusion, the results obtained confirm the multidirectional antimicrobial activity of the newly synthesized piperazine derivatives. Furthermore, in silico studies suggest that the tested compounds are likely to have good oral bioavailability. The results obtained will provide valuable data for further research into this interesting group of compounds. The library of compounds obtained is still the subject of pharmacological research aimed at finding new interesting biologically active compounds. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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14 pages, 9971 KiB

Open AccessArticle

The Enhanced Durability of AgCu Nanoparticle Coatings for Antibacterial Nonwoven Air Conditioner Filters

by Fang Zhou, Jiabing Peng, Yujie Tao, Longlai Yang, Dequan Yang and Edward Sacher

Molecules 2023, 28(14), 5446; https://doi.org/10.3390/molecules28145446 - 16 Jul 2023

Cited by 1 | Viewed by 1547

Abstract

Antibacterial nonwoven fabrics, incorporated with Ag, have been applied as masks and air conditioner filters to prevent the spread of disease from airborne respiratory pathogens. In this work, we present a comparison study of Ag ions: Ag and AgCu nanoparticles (NPs) coated onto [...] Read more.

Antibacterial nonwoven fabrics, incorporated with Ag, have been applied as masks and air conditioner filters to prevent the spread of disease from airborne respiratory pathogens. In this work, we present a comparison study of Ag ions: Ag and AgCu nanoparticles (NPs) coated onto nonwoven fabrics intended for use as air conditioner antibacterial filters. We illustrate their color changes and durability running in air conditioners using antibacterial activity testing and X-ray Photoelectron Spectroscopic (XPS) analysis. We found that AgCu NPs showed the best antibacterial efficacy and durability. XPS analysis indicated that the Ag concentration, on both the AgCu and Ag- NP-coated fibers, changed little. On the contrary, the Ag concentration on Ag ion-coated fibers decreased by ~30%, and the coated NPs aggregated over time. The color change in AgCu NP-coated fabric, from yellow to white, is caused by oxide shell formation over the NPs, with nearly 46% oxidized silver. Our results, both from antibacterial evaluation and wind blowing tests, indicate that AgCu NP-coated fibers have higher durability, while Ag ion-coated fibers have little durability in such applications. The enhanced durability of the AgCu NP-coated antibacterial fabrics can be attributed to stronger NP–fiber interactions and greater ion release. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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12 pages, 2483 KiB

Open AccessArticle

Scope and Limitations of Exploiting the Ability of the Chemosensitizer NV716 to Enhance the Activity of Tetracycline Derivatives against Pseudomonas aeruginosa

by Margot Draveny, Clémence Rose, Alexis Pinet, Laurent Ferrié, Bruno Figadère, Jean-Michel Brunel and Muriel Masi

Molecules 2023, 28(11), 4262; https://doi.org/10.3390/molecules28114262 - 23 May 2023

Cited by 1 | Viewed by 1134

Abstract

The spread of antibiotic resistance is an urgent threat to global health that requires new therapeutic approaches. Treatments for pathogenic Gram-negative bacteria are particularly challenging to identify due to the robust OM permeability barrier in these organisms. One strategy is to use antibiotic [...] Read more.

The spread of antibiotic resistance is an urgent threat to global health that requires new therapeutic approaches. Treatments for pathogenic Gram-negative bacteria are particularly challenging to identify due to the robust OM permeability barrier in these organisms. One strategy is to use antibiotic adjuvants, a class of drugs that have no significant antibacterial activity on their own but can act synergistically with certain antibiotics. Previous studies described the discovery and development of polyaminoisoprenyl molecules as antibiotic adjuvants with an OM effect. In particular, the compound NV716 has been shown to sensitize Pseudomonas aeruginosa to tetracycline antibiotics such as doxycycline. Here, we sought to explore the disruption of OM to sensitize P. aeruginosa to otherwise inactive antimicrobials using a series of tetracycline derivatives in the presence of NV716. We found that OM disruption expands the hydrophobicity threshold consistent with antibacterial activity to include hydrophobic molecules, thereby altering permeation rules in Gram-negative bacteria. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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18 pages, 3270 KiB

Open AccessArticle

Chalcone-Derived Lactones: Synthesis, Whole-Cell Biotransformation, and Evaluation of Their Antibacterial and Antifungal Activity

by Witold Gładkowski, Monika Siepka, Barbara Żarowska, Agata Białońska, Barbara Gawdzik, Mariusz Urbaniak and Czesław Wawrzeńczyk

Molecules 2023, 28(9), 3800; https://doi.org/10.3390/molecules28093800 - 28 Apr 2023

Viewed by 1158

Abstract

Four compounds with lactone moiety were synthesized from chalcone 1 in three- or four-step synthesis. γ-Bromo-δ-lactone 5 was the only product of bromolactonization of acid 4 whereas bromolactonization of ester 3, apart from lactone 5 also afforded its isomer 6 and two [...] Read more.

Four compounds with lactone moiety were synthesized from chalcone 1 in three- or four-step synthesis. γ-Bromo-δ-lactone 5 was the only product of bromolactonization of acid 4 whereas bromolactonization of ester 3, apart from lactone 5 also afforded its isomer 6 and two diastereoisomeric δ-hydroxy-γ-lactones 7 and 8. Lactone 8 was also obtained in 88% yield as a product of simultaneous dehalogenation and translactonization of γ-bromo-δ-lactone 5 by Penicillum frequentans AM 359. Chalcone-derived lactones 5–8 were subjected to the tests on antimicrobial activity and the results compared with activity of starting chalcone 1. Obtained lactones 5–8 in most cases limited the growth of tested bacterial and fungal strains. The highest activity was found for δ-hydroxy-γ-lactone 8 which completely inhibited the growth of Staphylococcus aureus, Fusarium graminearum, Aspergillus niger, and Alternaria sp. The introduction of lactone moiety into chalcone scaffold significantly improved antimicrobial activity of the compound: γ-bromo-δ-lactone 6 and δ-hydroxy-γ-lactone 8 were significantly stronger growth inhibitors of S. aureus and F. graminearum. In the case of the latter, a clear positive effect of the lactone function on the antifungal activity was also observed for γ-bromo-δ-lactone 5. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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13 pages, 7465 KiB

Open AccessArticle

Investigating the Antibacterial Effects of Synthetic Gamma-Lactam Heterocycles on Methicillin-Resistant Staphylococcus aureus Strains and Assessing the Safety and Effectiveness of Lead Compound MFM514

by Saiful Azmi Johari, Mastura Mohtar, Mohd Fazli Mohammat, Fatin Nur Ain Abdul Rashid, Muhamad Zulfaqar Bacho, Azman Mohamed, Mohamad Jemain Mohamad Ridhwan and Sharifah Aminah Syed Mohamad

Molecules 2023, 28(6), 2575; https://doi.org/10.3390/molecules28062575 - 12 Mar 2023

Cited by 1 | Viewed by 1460

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be one of the main causes of hospital-acquired infections in all regions of the world, while linezolid is one of the only commercially available oral antibiotics available against this dangerous gram-positive pathogen. In this study, the antibacterial [...] Read more.

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be one of the main causes of hospital-acquired infections in all regions of the world, while linezolid is one of the only commercially available oral antibiotics available against this dangerous gram-positive pathogen. In this study, the antibacterial activity from 32 analogues of synthetic gamma-lactam heterocycles against MRSA was determined. Amongst screened analogues for the minimum inhibitory concentration (MIC) assay, compound MFM514 displayed good inhibitory activity with MIC values of 7.8–15.6 µg/mL against 30 MRSA and 12 methicillin-sensitive S. aureus (MSSA) clinical isolates, while cytotoxicity evaluations displayed a mean inhibitory concentration (IC₅₀) value of > 625 µg/mL, displaying a potential to becoming as a lead compound. In subsequent animal studies for MFM514, a single-dose oral acute toxicity test revealed an estimated mean lethal dose (LD₅₀) value of <5000 mg/kg, while in the mice infection test, a mean effective dose (ED₅₀) value of 29.39 mg/kg was obtained via oral administration. These results suggest that gamma-lactam carbon skeleton, particularly MFM514, is highly recommended to be evaluated further as a new safe and efficacious orally delivered antibacterial agent against MRSA. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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16 pages, 4372 KiB

Open AccessArticle

Photoantibacterial Poly(vinyl)chloride Films Applying Curcumin Derivatives as Bio-Based Plasticizers and Photosensitizers

by Fábio M. S. Rodrigues, Iúri Tavares, Rafael T. Aroso, Lucas D. Dias, Carolina V. Domingos, Clara M. G. de Faria, Giusi Piccirillo, Teresa M. R. Maria, Rui M. B. Carrilho, Vanderlei S. Bagnato, Mário J. F. Calvete and Mariette M. Pereira

Molecules 2023, 28(5), 2209; https://doi.org/10.3390/molecules28052209 - 27 Feb 2023

Cited by 1 | Viewed by 1884

Abstract

Herein we describe the design of natural curcumin ester and ether derivatives and their application as potential bioplasticizers, to prepare photosensitive phthalate-free PVC-based materials. The preparation of PVC-based films incorporating several loadings of newly synthesized curcumin derivatives along with their standard solid-state characterization [...] Read more.

Herein we describe the design of natural curcumin ester and ether derivatives and their application as potential bioplasticizers, to prepare photosensitive phthalate-free PVC-based materials. The preparation of PVC-based films incorporating several loadings of newly synthesized curcumin derivatives along with their standard solid-state characterization is also described. Remarkably, the plasticizing effect of the curcumin derivatives in the PVC material was found to be similar to that observed in previous PVC–phthalate materials. Finally, studies applying these new materials in the photoinactivation of S. aureus planktonic cultures revealed a strong structure/activity correlation, with the photosensitive materials reaching up to 6 log CFU reduction at low irradiation intensities. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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15 pages, 3079 KiB

Open AccessArticle

Production and Characterization of New Biosurfactants/Bioemulsifiers from Pantoea alhagi and Their Antioxidant, Antimicrobial and Anti-Biofilm Potentiality Evaluations

by Badiaa Essghaier, Nesrine Mallat, Khaoula Khwaldia, Filomena Mottola, Lucia Rocco and Hédia Hannachi

Molecules 2023, 28(4), 1912; https://doi.org/10.3390/molecules28041912 - 17 Feb 2023

Cited by 4 | Viewed by 2052

Abstract

The present work aimed to develop rapid approach monitoring using a simple selective method based on a positive hemolysis test, oil spreading activity and emulsification index determinations. It is the first to describe production of biosurfactants (BS) by the endophytic Pantoea alhagi species. [...] Read more.

The present work aimed to develop rapid approach monitoring using a simple selective method based on a positive hemolysis test, oil spreading activity and emulsification index determinations. It is the first to describe production of biosurfactants (BS) by the endophytic Pantoea alhagi species. Results indicated that the new BS evidenced an E24 emulsification index of 82%. Fourier-transform infrared (FTIR) results mentioned that the described BS belong to the glycolipid family. Fatty acid profiles showed the predominance of methyl 2-hyroxydodecanoate in the cell membrane (67.00%) and methyl 14-methylhexadecanoate (12.05%). The major fatty acid in the BS was oleic acid (76.26%), followed by methyl 12-methyltetradecanoate (10.93%). Markedly, the BS produced by the Pantoea alhagi species exhibited antimicrobial and anti-biofilm activities against tested human pathogens. With superior antibacterial activity against Escherchia coli and Staphylococcus aureus, a high antifungal effect was given against Fusarium sp. with a diameter of zone of inhibition of 29.5 mm, 36 mm and 31 mm, obtained by BS dissolved in methanol extract. The DPPH assay indicated that the BS (2 mg/mL) showed a higher antioxidant activity (78.07 inhibition percentage). The new BS exhibited specific characteristics, encouraging their use in various industrial applications. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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16 pages, 16795 KiB

Open AccessArticle

Antimicrobial Activity of Some Steroidal Hydrazones

by Maia Merlani, Nanuli Nadaraia, Lela Amiranashvili, Anthi Petrou, Athina Geronikaki, Ana Ciric, Jasmina Glamoclija, Tamara Carevic and Marina Sokovic

Molecules 2023, 28(3), 1167; https://doi.org/10.3390/molecules28031167 - 24 Jan 2023

Cited by 3 | Viewed by 1337

Abstract

Twelve steroid based hydrazones were in silico evaluated using computer program PASS as antimicrobial agents. The experimental evaluation revealed that all compounds have low to moderate antibacterial activity against all bacteria tested, except for B. cereus with MIC at a range of 0.37–3.00 [...] Read more.

Twelve steroid based hydrazones were in silico evaluated using computer program PASS as antimicrobial agents. The experimental evaluation revealed that all compounds have low to moderate antibacterial activity against all bacteria tested, except for B. cereus with MIC at a range of 0.37–3.00 mg/mL and MBC at 0.75–6.00 mg/mL. The most potent appeared to be compound 11 with MIC/MBC of 0.75/1.5 mg/mL, respectively. The evaluation of antibacterial activity against three resistant strains MRSA, E. coli and P. aeruginosa demonstrated superior activity of compounds against MRSA compared with ampicillin, which did not show bacteriostatic or bactericidal activities. All compounds exhibited good antifungal activity with MIC of 0.37–1.50 mg/mL and MFC of 1.50–3.00 mg/mL, but with different sensitivity against fungi tested. According to docking studies, 14-alpha demethylase inhibition may be responsible for antifungal activity. Two compounds were evaluated for their antibiofilm activity. Finally, drug-likeness and docking prediction were performed. Full article

(This article belongs to the Special Issue Novel Antibacterial Agents: Discovery, Design, Synthesis, and Evaluation)

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