Natural products have been a rich source of compounds for drug discovery. However, their use has diminished in the past two decades, in part because of technical barriers to screening natural ...products in high-throughput assays against molecular targets. Here, we review strategies for natural product screening that harness the recent technical advances that have reduced these barriers. We also assess the use of genomic and metabolomic approaches to augment traditional methods of studying natural products, and highlight recent examples of natural products in antimicrobial drug discovery and as inhibitors of protein-protein interactions. The growing appreciation of functional assays and phenotypic screens may further contribute to a revival of interest in natural products for drug discovery.
Antimicrobial use in food-producing animals selects for antimicrobial resistance that can be transmitted to humans via food or other transmission routes. The World Health Organization (WHO) in 2005 ...ranked the medical importance of antimicrobials used in humans. In late 2017, to preserve the effectiveness of medically important antimicrobials for humans, WHO released guidelines on use of antimicrobials in food-producing animals that incorporated the latest WHO rankings.
WHO commissioned systematic reviews and literature reviews, and convened a Guideline Development Group (GDG) of external experts free of unacceptable conflicts-of-interest. The GDG assessed the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, and formulated recommendations using a structured evidence-to-decision approach that considered the balance of benefits and harms, feasibility, resource implications, and impact on equity. The resulting guidelines were peer-reviewed by an independent External Review Group and approved by the WHO Guidelines Review Committee.
These guidelines recommend reductions in the overall use of medically important antimicrobials in food-producing animals, including complete restriction of use of antimicrobials for growth promotion and for disease prevention (i.e., in healthy animals considered at risk of infection). These guidelines also recommend that antimicrobials identified as critically important for humans not be used in food-producing animals for treatment or disease control unless susceptibility testing demonstrates the drug to be the only treatment option.
To preserve the effectiveness of medically important antimicrobials, veterinarians, farmers, regulatory agencies, and all other stakeholders are urged to adopt these recommendations and work towards implementation of these guidelines.
The dramatic increase in antimicrobial resistance for pathogenic bacteria constitutes a key threat to human health. The Centers for Disease Control and Prevention has recently stated that the world ...is on the verge of entering the "post-antibiotic era", one where more people will die from bacterial infections than from cancer. Recently, nanoparticles (NPs) have emerged as new tools that can be used to combat deadly bacterial infections. Nanoparticle-based strategies can overcome the barriers faced by traditional antimicrobials, including antibiotic resistance. In this tutorial review, we have highlighted multiple nanoparticle-based approaches to eliminate bacterial infections, providing crucial insight into the design of elements that play critical roles in creating antimicrobial nanotherapeutics. In particular, we have focused on the pivotal role played by NP-surface functionality in designing nanomaterials as self-therapeutic agents and delivery vehicles for antimicrobial cargo.
Defensins: The natural peptide antibiotic Gao, Xihui; Ding, Junqiang; Liao, Chongbing ...
Advanced drug delivery reviews,
December 2021, 2021-12-00, 20211201, Letnik:
179
Journal Article
Recenzirano
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Defensins are a family of cationic antimicrobial peptides active against a broad range of infectious microbes including bacteria, viruses and fungi, playing important roles as innate ...effectors and immune modulators in immunological control of microbial infection. Their antibacterial properties and unique mechanisms of action have garnered considerable interest in developing defensins into a novel class of natural antibiotic peptides to fend off pathogenic infection by bacteria, particularly those resistant to conventional antibiotics. However, serious pharmacological and technical obstacles, some of which are unique to defensins and others are common to peptide drugs in general, have hindered the development and clinical translation of defensins as anti-infective therapeutics. To overcome them, several technologies have been developed, aiming for improved functionality, prolonged circulation time, enhanced proteolytic stability and bioavailability, and efficient and controlled delivery and release of defensins to the site of infection. Additional challenges include the alleviation of potential toxicity of defensins and their cost-effective manufacturing. In this review, we briefly introduce defensin biology, focus on various transforming strategies and practical techniques developed for defensins and their derivatives as antibacterial therapeutics, and conclude with a summation of future challenges and possible solutions.
Bacterial-infections are mostly due to bacteria in an adhering, biofilm-mode of growth and not due to planktonically growing, suspended-bacteria. Biofilm-bacteria are much more recalcitrant to ...conventional antimicrobials than planktonic-bacteria due to (1) emergence of new properties of biofilm-bacteria that cannot be predicted on the basis of planktonic properties, (2) low penetration and accumulation of antimicrobials in a biofilm, (3) disabling of antimicrobials due to acidic and anaerobic conditions prevailing in a biofilm, and (4) enzymatic modification or inactivation of antimicrobials by biofilm inhabitants. In recent years, new nanotechnology-based antimicrobials have been designed to kill planktonic, antibiotic-resistant bacteria, but additional requirements rather than the mere killing of suspended bacteria must be met to combat biofilm-infections. The requirements and merits of nanotechnology-based antimicrobials for the control of biofilm-infection form the focus of this Tutorial Review.
Chitosan has many desirable attributes e.g. antimicrobial properties and promoting wound healing, and is used in various applications. This article first discusses how degree of deacetylation (DD) ...and molecular weight (MW) impacts on what level of bioactivities chitosan manifests, then introduces the “molecular chain configuration” model to explain various possible mechanisms of antimicrobial interactions between chitosan with different MW and different types of bacteria. Similarly, the possible pathways of how chitosan reacts with cancer and the body's immune system to demonstrate immune and antitumor effects are also discussed by using this model. Moreover, the possible mechanisms of how chitosan enhances coagulation and wound healing are also discussed. With these beneficial bioactivities in mind, the application of chitosan in surgery, tissue engineering and oncology is outlined. This review concludes that as chitosan demonstrates many beneficial bioactivities via multiple mechanisms, it is an important polymer with a promising future in medicine.
The emergence of antibiotic-resistant microbes has stimulated research worldwide seeking new biologically active molecules. In this respect, synthetic antimicrobial peptides (SAMPs) have been ...suggested to overcome this problem. Although there are some online servers that provide putative SAMPs from protein sequences, the choice of the best peptide sequences for further analysis is still difficult. Therefore, the goal of this paper is not to launch a new tool but to provide a friendly workflow to characterize and predict potential SAMPs by employing existing tools. Using this proposed workflow, two peptides (PepGAT and PepKAA) were obtained and extensively characterized. These peptides damaged microbial membranes and cell walls, and induced overproduction of reactive oxygen species (ROS). Both peptides were found to assume random coil secondary structure in aqueous solution, organic solvent, and upon binding to negatively charged lipid systems. Peptides were also able to degrade formed biofilms but not to prevent biofilm formation. PepGAT was not resistant to proteolysis, whereas PepKAA was resistant to pepsin but not to pancreatin. Furthermore, both presented no hemolytic activity against red blood cells, even at a 10-fold higher concentration than the antimicrobial concentration. The pipeline proposed here is an easy way to design new SAMPs for application as alternatives to develop new drugs against human pathogenic microorganisms.
•Here is provided a workflow to facilitate the design of synthetic peptides.•Employing the workflow was possible to design two antimicrobial peptides.•PepGAT and PepKAA are potent antimicrobial peptides.•Both peptides have activity against human pathogenic bacteria and fungi.
Graphene materials have entered a phase of maturity in their development that is characterized by their explorative utilization in various types of applications and fields from electronics to ...biomedicine. Herein, we describe the recent advances made with graphene‐related materials in the biomedical field and the challenges facing these exciting new tools both in terms of biological activity and toxicological profiling in vitro and in vivo. Graphene materials today have mainly been explored as components of biosensors and for construction of matrices in tissue engineering. Their antimicrobial activity and their capacity to act as drug delivery platforms have also been reported, however, not as coherently. This report will attempt to offer some perspective as to which areas of biomedical applications can expect graphene‐related materials to constitute a tool offering improved functionality and previously unavailable options.
Graphene offers one of the most exciting tools for biomedicine due to its spectacular physicochemical characteristics. This Progress Report attempts to provide a snapshot of the current‐state‐of‐the‐art of graphene‐related materials in biomedical applications and a perspective on the challenges around the development of biologically active and safe graphene‐based technologies that could serve medical needs.
Chia (
L.) is a small seed that comes from an annual herbaceous plant,
L. In recent years, usage of Chia seeds has tremendously grown due to their high nutritional and medicinal values. Chia was ...cultivated by Mesopotamian cultures, but then disappeared for centuries until the middle of the 20th century, when it was rediscovered. Chia seeds contain healthy ω-3 fatty acids, polyunsaturated fatty acids, dietary fiber, proteins, vitamins, and some minerals. Besides this, the seeds are an excellent source of polyphenols and antioxidants, such as caffeic acid, rosmarinic acid, myricetin, quercetin, and others. Today, chia has been analyzed in different areas of research. Researches around the world have been investigating the benefits of chia seeds in the medicinal, pharmaceutical, and food industry. Chia oil is today one of the most valuable oils on the market. Different extraction methods have been used to produce the oil. In the present study, an extensive overview of the chemical composition, nutritional properties, and antioxidant and antimicrobial activities, along with extraction methods used to produce chia oil, will be discussed.
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