Characterization of potential elastase inhibitor-peptides regulated by a molecular switch for wound dressings applications

Potential Antioxidant and Enzyme Inhibitory Effects of Nanoliposomal Formulation Prepared from Salvia aramiensis Rech. f. Extract

Salvia aramiensis Rech. f. is a species that grows only in Hatay, Turkey and is used as a traditional stomachic tea. Neither the chemical composition nor the potential bioactivity of the plant has been investigated before. Antioxidant activity (1,1-Diphenyl-2-picrylhydrazyl Radical (DPPH^●) and 2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS^+●) radical scavenging and β-carotene/linoleic acid co-oxidation) of 70% methanol, 70% ethanol extracts, and 2% infusion obtained from S. aramiensis aerial parts were determined. The effect of 70% methanol extract on collagenase and elastase enzyme inhibition and its chemical composition via chromatographic methods (LC-MS/MS and HPLC) were analyzed. Nanoliposomes were developed with 70% methanol extract, were characterized, and were evaluated. The key parameters for the most active 70% methanol extract included the following DPPH^•EC₅₀: 28.4 µg/mL, Trolox equivalent antioxidant capacity (TEAC)/ABTS: 1.77 ± 0.09 mmol/L/Trolox. Furthermore 70% methanol extract showed more than 50% inhibition on collagenase and elastase enzymes at all the concentrations. The main component of the extract, rich in phenolic compounds, has been identified as rosmarinic acid; 83.7 µg/mL extract was released from the nanoliposomal formulation. The extract and its formulation are found to be nontoxic on the L929 fibroblast cell line. This study successfully developed a long-term antioxidant and enzyme inhibitory formulation containing S. aramiensis, which has been used safely among the public for years.

Cellulose-Based Biosensors for Esterase Detection

Cellulose has emerged as an attractive substrate for the production of economical, disposable, point-of-care (POC) analytical devices. Development of novel methods of (bio)activation is central to broadening the application space of cellulosic materials. Ironically, such efforts are stymied by the inherent biocompatibility and recalcitrance of cellulose fibers. Here, we have elaborated a versatile, chemo-enzymatic approach to activate cellulosic materials for CuAAC "click chemistry", to develop new fluorogenic esterase sensors. Gentle, aqueous modification conditions facilitate broad applicability to cellulose papers, gauzes, and hydrogels. Tethering of the released fluorophore to the cellulose surface prevents signal degradation due to diffusion and enables straightforward, sensitive visualization with a simple light source in resource-limited situations.

Advances in the treatment of chronic wounds: a patent review

INTRODUCTION

About 2% of the Western world population suffer from chronic wounds, resulting from underlying disorders (e.g., diabetes, excessive pressure, vascular insufficiencies and vasculitis), with a significant adverse effect on Quality of Life. Despite high incidence and economic burden, management of chronic wounds is still far from effective and novel therapies are in urgent need. Wound healing is a dynamic process of transient expression, function and clearance of mediators, enzymes and cell types. Failure to initiate, terminate or regulate leads to pathologic wound healing.

AREAS COVERED

The present review discusses patents of the seven most promising classes of biological agents, mostly published in 2009 - 2014 (CYP11B1 inhibitors, peptide growth factors, prolyl-4-hydroxylase and matrix metalloproteinase inhibitors, bone marrow-derived mesenchymal stem cells, elastase and connexin43 inhibitors). Relevant information from peer-reviewed journals is also presented.

EXPERT OPINION

The aforementioned biological agents have different mechanisms of action, and considering the multifactorial pathogenesis of chronic wounds, they hold promise in treating chronic wounds. However, as administration of a certain biological agent may be beneficial in an early phase, it may slow down wound healing in a later phase. Basic and clinical research on chronic wound healing should therefore investigate the efficacy of these agents, alone and in concert, during the consecutive phases of wound healing.

In vitro studies on the cytotoxicity, and elastase and tyrosinase inhibitory activities of marigold (Tagetes erecta L.) flower extracts

Marigold (Tagetes erecta L.) has long been used as a medicinal herb for a number of therapeutic activities. In the present study, the cytotoxicities of ethanol and ethyl acetate extracts of marigold flowers and their inhibitory effects on elastase and tyrosinase enzymes were investigated. An MTT assay was performed to measure the cytotoxicity of these two extracts on the H460 lung cancer and the Caco-2 colon cancer cell lines. An elastase assay kit, based on the digestion of a non-fluorescent elastin substrate to highly fluorescent fragments by elastase, was used for the elastase inhibition assay. Tyrosinase inhibition activity was investigated using the dopachrome method with L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate. The data obtained in this study demonstrated that the extracts were nontoxic to H460 and Caco-2 cell lines. The elastase inhibition activities of ethanol (250 μg/ml) and ethyl acetate (125 μg/ml) extracts were found to be significantly higher than that of the negative control. The tyrosinase inhibition activities of ethanol and ethyl acetate extracts, in terms of the mean inhibition concentration (IC₅₀), were 1,078 and 1,467 μg/ml, respectively. To the best of our knowledge, the present study has demonstrated for the first time that marigold flower extracts possess tyrosinase inhibition activity. The activities of ethanol and ethyl acetate extracts of marigold flowers were investigated in vitro and indicated that these extracts possess useful properties that may be of interest for cosmetic development.

Citrate-linked keto- and aldo-hexose monosaccharide cellulose conjugates demonstrate selective human neutrophil elastase-lowering activity in cotton dressings

Sequestration of harmful proteases as human neutrophil elastase (HNE) from the chronic wound environment is an important goal of wound dressing design and function. Monosaccharides attached to cellulose conjugates as ester-appended aldohexoses and ketohexoses were prepared on cotton gauze as monosccharide-citrate-cellulose-esters for HNE sequestration. The monosaccharide-cellulose analogs demonstrated selective binding when the derivatized cotton dressings were measured for sequestration of HNE. Each monosaccharide-cellulose conjugate was prepared as a cellulose citrate-linked monosaccharide ester on the cotton wound dressing, and assayed under wound exudate-mimicked conditions for elastase sequestration activity. A series of three aldohexose and four ketohexose ester cellulose conjugates were prepared on cotton gauze through citric acid-cellulose cross linking esterification. The monosaccharide portion of the conjugate was characterized by hydrolysis of the citrate-monosaccharide ester bond, and subsequent analysis of the free monosaccharide with high performance anion exchange chromatography. The ketohexose and aldohexose conjugate levels on cotton were quantified on cotton using chromatography and found to be present in milligram/gram amounts. The citrate-cellulose ester bonds were characterized with FTIR. Ketohexose-citrate-cellulose conjugates sequestered more elastase activity than aldohexose-citrate-cellulose conjugates. The monosaccharide cellulose conjugate families each gave distinctive profiles in elastase-lowering effects. Possible mechanisms of elastase binding to the monosaccharide-cellulose conjugates are discussed.

Influence of secretory leukocyte protease inhibitor-based peptides on elastase activity and their incorporation in hyaluronic acid hydrogels for chronic wound therapy

Chronic nonhealing skin wounds, such as leg ulcers and pressure sores, represent a major clinical problem and a financial burden for the health care systems. Chronic wounds are characterized by prolonged inflammatory phase that results in high levels of elastase, reactive oxygen species (ROS), and diminished growth factor activity. Under normal physiological conditions, elastase is a powerful host defence and its activity is regulated by endogenous inhibitors. The unrestrained elastase activity in chronic wounds may be tuned by exogenous active materials that inhibit elastase. Secretory leucocyte protease inhibitor, SLPI, is a potent endogenous inhibitor of elastase. Peptide fragments, KRCCPDTCGIKCL (Pep4) and KRMMPDTMGIKML (Pep4M), selected from SLPI primary structure were studied as potential elastase inhibitors. Kinetic studies performed for human neutrophil elastase (HNE) and porcine pancreatic elastase (PPE) in presence of these peptides revealed that both behave as uncompetitive and noncompetitive inhibitors of HNE and PPE, respectively. The influence of ROS and albumin on Pep4 and Pep4M inhibitory activity toward elastase reveals that this mixture increases the inhibitory activity of both peptides. These peptides were incorporated in hyaluronic acid hydrogels to evaluate the possibility of being used as active compounds in a drug delivery system. Assessment of HNE and PPE activity in the presence of these hydrogels formulations revealed a considerable decrease in enzyme activity. Although, only moderated elastase inhibition was observed, these peptides represent potential candidates for chronic wound applications, as there is no need for complete elastase inhibition in the normal wound healing process.