Antimicrobial effects of coprisin on wounds infected with Staphylococcus aureus in rats

Facilitation of infectious and non-infectious wound healing using Morus nigra fruit extract ointment: An in vitro and in vivo study

Accelerating wound healing, as well as preventing infection and scar formation are among the most important medical challenges. This study aims to examine the antimicrobial, immunomodulatory, and anticancer properties of Morus nigra. The antimicrobial activities of ripe and unripe M. nigra fruit (MNF) extracts were tested. HPLC was employed to measure the components in the extract. Oserin ointment was made with 8 % extract. To test the ointment, 48 Wistar rats were randomly assigned into eight groups. The ointment was used daily by treating the wounds. Tissue histology and wound healing were assessed over nine days. Comparative evaluation of wound healing was conducted by analyzing TGF-β, TNF-α, and IL-1 mRNA levels. Finally, cytotoxic effects on AGS cancer and NIH-3 T3 fibroblast cells were examined. The ANOVA test and Prsim program were used for statistical analysis. Unripe MNF extract had good antimicrobial properties in standard and nosocomial strains. The most abundant compound in the extract was ascorbic acid (0.0441 mg/10 mg extract), followed by naringenin and gallic acid. In all groups treated with MNF extract ointment, a significant reduction in wound area was observed compared to other groups (p < 0.05). After six days of treatment, the microbial load was uncountable. In the microscopic studies of the wounds, a significant increase was observed in fibroblasts, angiogenesis, and in neutrophils in the first days as well as a decrease in the final days. The treatment caused a significant decline in the expression of IL-1 and TNF-α genes, as well as an increase in the expression of TGF-β (p < 0.05). This extract had no significant cytotoxic effects on human fibroblast cells (p > 0.05). In general, it can be concluded that the unripe MNF extract ointment can be a suitable option for the treatment of infectious and non-infectious skin wounds.

Antimicrobial-wound healing peptides: Dual-function molecules for the treatment of skin injuries

Chronic non-healing wounds caused by microbial infections extend the necessity for hospital care and constitute a public health problem and a great financial burden. Classic therapies include a wide range of approaches, from wound debridement to vascular surgery. Antimicrobial peptides (AMPs) are a preserved trait of the innate immune response among different animal species, with known effects on the immune system and microorganisms. Thus, AMPs may represent promising candidates for the treatment of chronic wounds with dual functionality in two of the main agents that lead to this condition, proliferation of microorganisms and uncontrolled inflammation. Here, our goal is to critically review AMPs with wound healing properties. We strongly believe that these dual-function peptides alone, or in combination with other wound healing strategies, constitute an underexplored field that researchers can take advantage of.

Antimicrobial peptides - Unleashing their therapeutic potential using nanotechnology

Antimicrobial peptides (AMPs) are potent, mostly cationic, and amphiphilic broad-spectrum host defense antimicrobials that are produced by all organisms ranging from prokaryotes to humans. In addition to their antimicrobial actions, they modulate inflammatory and immune responses and promote wound healing. Although they have clear benefits over traditional antibiotic drugs, their wide therapeutic utilization is compromised by concerns of toxicity, stability, and production costs. Recent advances in nanotechnology have attracted increasing interest to unleash the AMPs' immense potential as broad-spectrum antibiotics and anti-biofilm agents, against which the bacteria have less chances to develop resistance. Topical application of AMPs promotes migration of keratinocytes and fibroblasts, and contributes significantly to an accelerated wound healing process. Delivery of AMPs by employing nanotechnological approaches avoids the major disadvantages of AMPs, such as instability and toxicity, and provides a controlled delivery profile together with prolonged activity. In this review, we provide an overview of the key properties of AMPs and discuss the latest developments in topical AMP therapy using nanocarriers. We use chronic hard-to-heal wounds-complicated by infections, inflammation, and stagnated healing-as an example of an unmet medical need for which the AMPs' wide range of therapeutic actions could provide the most potential benefit. The use of innovative materials and sophisticated nanotechnological approaches offering various possibilities are discussed in more depth.

The transcriptome analysis of Protaetia brevitarsis Lewis larvae

Larvae of the pest Protaetia brevitarsis are used to treat infections in traditional Chinese medicine. However, genomic information about this non-model species is currently lacking. To better understand the fundamental biology of this non-model species, its transcriptome was obtained using next generation sequencing and then analyzed. A total of 7.62 Gb of clean reads were obtained, which were assembled into 169,087 transcripts corresponding to 142,000 annotated unigenes. These unigenes were functionally classified according to Gene Ontology (GO), euKaryotic Ortholog Groups of proteins (KOG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations. A total of 41,921 unigenes were assigned to 56 GO terms, 21,454 unigenes were divided among 26 KOG categories, and 16,368 unigenes were assigned to 32 KEGG pathways. In addition, 19,144 simple sequence repeats (SSRs) were identified. Furthermore, several kinds of natural antimicrobial peptides and proteins, 4 histones with potential antimicrobial activity, and 41 potential antimicrobial peptide sequences were identified. These data are the first reported whole transcriptome sequence of P. brevitarsis larvae, which represents a valuable genomic resource for studying this species, thus promoting the utilization of its medical potential.

Bee-derived antibacterial peptide, defensin-1, promotes wound re-epithelialisation in vitro and in vivo

Royal jelly (RJ) has successfully been used as a remedy in wound healing. RJ has multiple effects, including antibacterial, anti-inflammatory and immunomodulatory activities, in various cell types. However, no component(s) (other than antibacterial) have been identified in RJ-accelerated wound healing. In this study, we demonstrate that keratinocytes are responsible for the elevated production of matrix metalloproteinase-9 (MMP-9) after incubation with a water extract of RJ. Furthermore, the keratinocyte migration and wound closure rates were significantly increased in the presence of RJ extract. MMP-9 production was reduced significantly following proteinase K treatment but remained stable after heat treatment, indicating that active component(s) have a proteinous character. To identify the component responsible for inducing MMP-9 production, RJ extract was fractionated using C18 RP-HPLC. In fractions exhibiting stimulatory activity, we immunochemically detected the bee-derived antibacterial peptide, defensin-1. Defensin-1 was cloned, and recombinant peptide was produced in a baculoviral expression system. Defensin-1 stimulated MMP-9 secretion from keratinocytes and increased keratinocyte migration and wound closure in vitro. In addition, defensin-1 promoted re-epithelisation and wound closure in uninfected excision wounds. These data indisputably demonstrate that defensin-1, a regular but concentration variable factor found in honey and RJ, contributes to cutaneous wound closure by enhancing keratinocyte migration and MMP-9 secretion.

New Is Old, and Old Is New: Recent Advances in Antibiotic-Based, Antibiotic-Free and Ethnomedical Treatments against Methicillin-Resistant Staphylococcus aureus Wound Infections

Staphylococcus aureus is the most common pathogen of wound infections. Thus far, methicillin-resistant S. aureus (MRSA) has become the major causative agent in wound infections, especially for nosocomial infections. MRSA infections are seldom eradicated by routine antimicrobial therapies. More concerning, some strains have become resistant to the newest antibiotics of last resort. Furthermore, horizontal transfer of a polymyxin resistance gene, mcr-1, has been identified in Enterobacteriaceae, by which resistance to the last group of antibiotics will likely spread rapidly. The worst-case scenario, "a return to the pre-antibiotic era", is likely in sight. A perpetual goal for antibiotic research is the discovery of an antibiotic that lacks resistance potential, such as the recent discovery of teixobactin. However, when considering the issue from an ecological and evolutionary standpoint, it is evident that it is insufficient to solve the antibiotic dilemma through the use of antibiotics themselves. In this review, we summarized recent advances in antibiotic-based, antibiotic-free and ethnomedical treatments against MRSA wound infections to identify new clues to solve the antibiotic dilemma. One potential solution is to use ethnomedical drugs topically. Some ethnomedical drugs have been demonstrated to be effective antimicrobials against MRSA. A decline in antibiotic resistance can therefore be expected, as has been demonstrated when antibiotic-free treatments were used to limit the use of antibiotics. It is also anticipated that these drugs will have low resistance potential, although there is only minimal evidence to support this claim to date. More clinical trials and animal tests should be conducted on this topic.

Effects of cyclotides against cutaneous infections caused by Staphylococcus aureus

The main bacterium associated with skin infection is Staphylococcus aureus, occurring especially in infections acquired via surgical wounds, commonly leading to lethal hospital-acquired infections, emphasizing the importance of identifying new antimicrobial compounds. Among them, cyclotides have gained interest due to their high stability and multifunctional properties. Here, cycloviolacin 2 (CyO2) and kalata B2 (KB2) were evaluated to determinate their anti-staphylococcal activities using a subcutaneous infection model. Anti-staphylococcal activities of 50mM for KB2 and 25mM for CyO2 were detected with no cytotoxic activities against RAW 264.7 monocytes. In the in vivo assays, both cyclotides reduced bacterial load and CyO2 demonstrated an increase in the phagocytosis index, suggesting that the CyO2 in vivo anti-staphylococcal activity may be associated with phagocytic activity, additionally to direct anti-pathogenic activity.