Antimicrobial and Antioxidant Activities of Natural Compounds and Synthetic Derivatives: Pharmacological Screening and Mechanism of Action

A special issue of Antibiotics (ISSN 2079-6382). This special issue belongs to the section "Novel Antimicrobial Agents".

Deadline for manuscript submissions: closed (1 October 2021) | Viewed by 7964

Special Issue Editors

Department of Pharmacy, University of Naples Federico II, 80131 Naples, Italy
Interests: bacteria and yeast infections; RAPD analysis of fungal and bacteria community; bacterial resistance; MDR; antimicrobial peptides; natural compounds and their antimicrobial activity; biofilm
Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, 80131 Naples, Italy
Interests: bacterial and fungal mechanisms of persistence in the host; molecular epidemiology and characterization of antibiotic resistance determinants in bacteria of clinical interest; antibacterial and antifungal effects of unconventional antimicrobial agents
Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, 80126 Naples, Italy
Interests: isolation and structure elucidation of natural compounds from microorganisms and plants; synthesis and derivatization of natural products; chromatographic techniques; analytical and spectroscopic techniques
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Special Issue Information

Dear Colleagues,

Antimicrobial agents have represented a very powerful tool in the clinical management of infectious diseases since their first discovery in the early 20th century. However, the growing number of multi-drug resistant microorganisms has drastically reduced antibiotic efficacy, due also to their not always appropriate or excessive use. In the last few decades, only a few new antibiotics have been introduced, leading to depleted antibiotic reserves and, thus, reduced possibility to manage multi-resistant infections. This new scenario has forced worldwide research into the screening of new antimicrobials.

Oxidative stress occurs when there is an imbalance between free radical activity and antioxidant defence activity. When functioning properly, free radicals can help fight off pathogens, but if in excess they can contribute to the pathophysiology of several chronic diseases, such as cancer, diabetes, and neurodegenerative and cardiovascular diseases. In recent years, it has been shown that some infections also cause oxidative stress.

Natural products from plants, fungi and bacteria have been successfully used in the past for their antimicrobial and antioxidant activity. Many bacteria or yeast metabolites have been used as starting chemical skeletons for the generation of semi-synthetic drugs with improved biological activity. However, the search for new compounds with antimicrobial and antioxidant properties remains an area still largely to be explored.

The goal of this Special Issue is the exploration of new compounds of natural origin, but also their analogues of synthesis, to develop new and urgently needed antimicrobial and antioxidant therapies.

Prof. Elisabetta Buommino
Prof. Maria Rosaria Catania
Prof. Marina DellaGreca
Guest Editors

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Keywords

  • New natural antimicrobial compounds
  • Synthetic natural product derivatives
  • Antimicrobial effects (included anti biofilm activity)
  • Joint antimicrobial and antioxidant properties
  • Molecular mechanisms of novel compounds
  • Activity as disinfectants
  • Clinical applications
  • Multidrug resistant strains
  • Discovery of novel therapies to overcome known antimicrobial resistance mechanisms and/or to restore susceptibility to conventional antibiotics (synergistic effect)

Published Papers (3 papers)

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Research

16 pages, 4916 KiB  
Article
Synergism of a Novel 1,2,4-oxadiazole-containing Derivative with Oxacillin against Methicillin-Resistant Staphylococcus aureus
by Elisabetta Buommino, Simona De Marino, Martina Sciarretta, Marialuisa Piccolo, Carmen Festa and Maria Valeria D’Auria
Antibiotics 2021, 10(10), 1258; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10101258 - 16 Oct 2021
Cited by 6 | Viewed by 1980
Abstract
Staphylococcusaureus is an important opportunistic pathogen that causes many infections in humans and animals. The inappropriate use of antibiotics has favored the diffusion of methicillin-resistant S. aureus (MRSA), nullifying the efforts undertaken in the discovery of antimicrobial agents. Oxadiazole heterocycles represent [...] Read more.
Staphylococcusaureus is an important opportunistic pathogen that causes many infections in humans and animals. The inappropriate use of antibiotics has favored the diffusion of methicillin-resistant S. aureus (MRSA), nullifying the efforts undertaken in the discovery of antimicrobial agents. Oxadiazole heterocycles represent privileged scaffolds for the development of new drugs because of their unique bioisosteric properties, easy synthesis, and therapeutic potential. A vast number of oxadiazole-containing derivatives have been discovered as potent antibacterial agents against multidrug-resistant MRSA strains. Here, we investigate the ability of a new library of oxadiazoles to contrast the growth of Gram-positive and Gram-negative strains. The strongest antimicrobial activity was obtained with compounds 3 (4 µM) and 12 (2 µM). Compound 12, selected for further evaluation, was found to be noncytotoxic on the HaCaT cell line up to 25 µM, bactericidal, and was able to improve the activity of oxacillin against the MRSA. The highest synergistic interaction was obtained with the combination values of 0.78 μM for compound 12, and 0.06 μg/mL for oxacillin. The FIC index value of 0.396 confirms the synergistic effect of compound 12 and oxacillin. MRSA treatment with compound 12 reduced the expression of genes included in the mec operon. In conclusion, 12 inhibited the growth of the MRSA and restored the activity of oxacillin, thus resulting in a promising compound in the treatment of MRSA infection. Full article
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12 pages, 2361 KiB  
Article
Synergistic Effect of Abietic Acid with Oxacillin against Methicillin-Resistant Staphylococcus pseudintermedius
by Elisabetta Buommino, Adriana Vollaro, Francesca P. Nocera, Francesca Lembo, Marina DellaGreca, Luisa De Martino and Maria R. Catania
Antibiotics 2021, 10(1), 80; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics10010080 - 15 Jan 2021
Cited by 14 | Viewed by 2392
Abstract
Resin acids are valued in traditional medicine for their antiseptic properties. Among these, abietic acid has been reported to be active against methicillin-resistant Staphylococcus aureus (MRSA) strains. In veterinary healthcare, the methicillin-resistant Staphylococcus pseudintermedius (MRSP) strain is an important reservoir of antibiotic resistance [...] Read more.
Resin acids are valued in traditional medicine for their antiseptic properties. Among these, abietic acid has been reported to be active against methicillin-resistant Staphylococcus aureus (MRSA) strains. In veterinary healthcare, the methicillin-resistant Staphylococcus pseudintermedius (MRSP) strain is an important reservoir of antibiotic resistance genes including mecA. The incidence of MRSP has been increasing, and treatment options in veterinary medicine are partial. Here, we investigated the antimicrobial and antibiofilm properties of abietic acid against three MRSP and two methicillin-susceptible Staphylococcus pseudintermedius (MSSP) strains, isolated from diseased pet animals and human wound samples. Abietic acid showed a significant minimal inhibitory concentration (MIC) value ranging from 32 to 64 μg/mL (MRSPs) and 8 μg/mL (MSSP). By checkerboard method we demonstrated that abietic acid increased oxacillin susceptibility of MRSP strains, thus showing a synergistic interaction with oxacillin. Abietic acid was also able to contrast the vitality of treated MSSP and MRSP1 biofilms at 20 μg/mL and 40 μg/mL, respectively. Finally, the compound moderately reduced mecA, mecR1 and mec1 gene expression. In conclusion, the results here reported demonstrate the antimicrobial activity of abietic acid against MRSP and support the use of this compound as a potential therapeutic agent to be used in combinatorial antibiotic therapy. Full article
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12 pages, 1729 KiB  
Article
Novel Antimicrobial Peptide from Temporin L in The Treatment of Staphylococcus pseudintermedius and Malassezia pachydermatis in Polymicrobial Inter-Kingdom Infection
by Rosa Bellavita, Adriana Vollaro, Maria Rosaria Catania, Francesco Merlino, Luisa De Martino, Francesca Paola Nocera, Marina DellaGreca, Francesca Lembo, Paolo Grieco and Elisabetta Buommino
Antibiotics 2020, 9(9), 530; https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics9090530 - 22 Aug 2020
Cited by 15 | Viewed by 2626
Abstract
Interkingdom polymicrobial diseases are caused by different microorganisms that colonize the same niche, as in the case of yeast-bacteria coinfections. The latter are difficult to treat due the absence of any common therapeutic target for their elimination, both in animals and humans. Staphylococcus [...] Read more.
Interkingdom polymicrobial diseases are caused by different microorganisms that colonize the same niche, as in the case of yeast-bacteria coinfections. The latter are difficult to treat due the absence of any common therapeutic target for their elimination, both in animals and humans. Staphylococcus pseudintermedius and Malassezia pachydermatis belong to distinct kingdoms. They can colonize the same skin district or apparatus being the causative agents of fastidious pet animals’ pathologies. Here we analysed the antimicrobial properties of a panel of 11 peptides, derived from temporin L, against Malassezia pachydermatis. Only peptide 8 showed the best mycocidal activity at 6.25 μM. Prolonged application of peptide 8 did not cause M. pachydermatis drug-resistance. Peptide 8 was also able to inhibit the growth of Staphylococcus pseudintermedius, regardless of methicillin resistance, at 1.56 μM for methicillin-susceptible S. pseudintermedius (MSSP) and 6.25 μM for methicillin-resistant S. pseudintermedius (MRSP). Of interest, peptide 8 increased the susceptibility of MRSP to oxacillin. Oxacillin MIC value reduction was of about eight times when used in combination with peptide 8. Finally, the compound affected the vitality of bacteria embedded in S. pseudintermedius biofilm. In conclusion, peptide 8 might represent a valid therapeutic alternative in the treatment of interkingdom polymicrobial infections, also in the presence of methicillin-resistant bacteria. Full article
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