In vitro and in vivo burn healing study of standardized propolis: Unveiling its antibacterial, antioxidant and anti-inflammatory actions in relation to its phytochemical profiling.

BACKGROUND: Natural propolis has been used since decades owing to its broad-spectrum activities. Burn injuries are a global health problem with negative impacts on communities. Bacterial infections usually accompany burns, which demand implementation of antibiotics. Antibiotics abuse led to emergence of microbial drug resistance resulting in poor treatment outcomes. In such instances, the promising alternative would be natural antimicrobials such as propolis. OBJECTIVE: Full chemical profiling of propolis and evaluation of in vitro antibacterial, antioxidant and anti-inflammatory activities as well as in vivo burn healing properties. METHODS: Chemical profiling of propolis was performed using Liquid chromatography (UHPLC/MS-PDA and HPLC-PDA). In vitro assessment was done using Disc Diffusion susceptibility test against Staphylococcus aureus and infected burn wound mice model was used for in vivo assessment. In vitro antioxidant properties of propolis were assessed using DPPH, ABTS and FRAP techniques. The anti-inflammatory effect of propolis was assessed against lipopolysaccharide/interferon-gamma mediated inflammation. RESULTS: UHPLC/MS-PDA results revealed identification of 71 phytochemicals, mainly flavonoids. Upon flavonoids quantification (HPLC-PDA), Pinocembrin, chrysin and galangin recorded high content 21.58±0.84, 22.73±0.68 and 14.26±0.70 mg/g hydroalcoholic propolis extract, respectively. Propolis showed concentration dependent antibacterial activity in vitro and in vivo burn healing via wound diameter reduction and histopathological analysis without signs of skin irritation in rabbits nor sensitization in guinea pigs. Propolis showed promising antioxidant IC50 values 46.52±1.25 and 11.74±0.26 µg/mL whereas FRAP result was 445.29±29.9 µM TE/mg. Anti-inflammatory experiment results showed significant increase of Toll-like receptor 4 (TLR4), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) mRNA levels. Nitric oxide and iNOS were markedly increased in Griess assay and western blot respectively. However, upon testing propolis against LPS/IFN-γ-mediated inflammation, TLR4, IL-6 and TNF-α expression were downregulated at transcriptional and post-transcriptional levels. CONCLUSION: Propolis proved to be a promising natural burn healing agent through its antibacterial, antioxidant and anti-inflammatory activities.

Intact Transition Epitope Mapping-Force Differences between Original and Unusual Residues (ITEM-FOUR).

Antibody-based point-of-care diagnostics have become indispensable for modern medicine. In-depth analysis of antibody recognition mechanisms is the key to tailoring the accuracy and precision of test results, which themselves are crucial for targeted and personalized therapy. A rapid and robust method is desired by which binding strengths between antigens and antibodies of concern can be fine-mapped with amino acid residue resolution to examine the assumedly serious effects of single amino acid polymorphisms on insufficiencies of antibody-based detection capabilities of, e.g., life-threatening conditions such as myocardial infarction. The experimental ITEM-FOUR approach makes use of modern mass spectrometry instrumentation to investigate intact immune complexes in the gas phase. ITEM-FOUR together with molecular dynamics simulations, enables the determination of the influences of individually exchanged amino acid residues within a defined epitope on an immune complex's binding strength. Wild-type and mutated epitope peptides were ranked according to their experimentally determined dissociation enthalpies relative to each other, thereby revealing which single amino acid polymorphism caused weakened, impaired, and even abolished antibody binding. Investigating a diagnostically relevant human cardiac Troponin I epitope for which seven nonsynonymous single nucleotide polymorphisms are known to exist in the human population tackles a medically relevant but hitherto unsolved problem of current antibody-based point-of-care diagnostics.

GC-MS Profiling of Naturally Extracted Essential Oils: Antimicrobial and Beverage Preservative Actions.

The purpose of this study was to demonstrate the antimicrobial effects of natural essential oils (EO) and determine their preservative action. Eight natural essential oils were tested against Staphylococcus aureus, Escherichia coli, and Candida albicans representing gram positive, gram negative, and fungi, respectively. The plant materials were used in this study viz. Thymus vulgaris-thyme (TV), Mentha virdis (MV), Mentha longifolia (ML), Rosmarinus officinalis-rosemary (RO), Lavandula dentata-lavender (LD), Origanum majorana-oregano (OM), which belong to the Lamiaceae family. The other two plants were Cymbopogon citratus-lemon grass (family Poaceae) (CC), and Eucalyptus globulus (family Myrtaceae) (EG). Employing the disc diffusion susceptibility test, minimum inhibitory and minimum bactericidal concentrations were estimated for each oil, followed by the addition of oils to pasteurized apple juice after microbial induction. The results revealed that thyme oil showed the maximum zone of inhibition against all tested microbes enriched with monoterpenes class viz. eucalyptol (24.3%), thymol (17.4%), and γ-terpinene (15.2%). All other tested oils exhibited a concentration-dependent inhibition of growth and their MIC ranged from 0.1 to 100 µL/mL. The recorded minimum bactericidal concentration values were apparently double the minimum inhibitory concentration. The EO of Mentha virdis followed by Mentha longifolia showed maximum antimicrobial activity against the tested organisms in pasteurized apple juice. A gas chromatography-mass spectroscopy (GC-MS) analysis of lemon grass, thyme, and Mentha virdis essential oils showed their enrichment with monoterpenes class recording 97.10, 97.04, and 97.61%, respectively.

Characterization and anti-biofilm activity of bacteriophages against urinary tract Enterococcus faecalis isolates.

Strong biofilm-forming Enterococcus feacalis urinary tract pathogens (n = 35) were used to determine the lytic spectrum of six bacteriophages isolated from sewage samples. Only 17 Enterococcus feacalis isolates gave lytic zones with the tested bacteriophages from which five isolates were susceptible to all of them. The isolated enterococcal phages are characterized by wide range of thermal (30-90 °C) and pH (3-10) stability. They belong to order Caudovirales, from which four bacteriophages (EPA, EPB, EPD, EPF) belong to family Myoviridae and two (EPC, EPE) belong to family Siphoviridae. In addition, they have promising antibiofilm activity against the tested strong-forming biofilm E. faecalis isolates. The enterococcal phages reduced the formed and preformed biofilms to a range of 38.02-45.7% and 71.0-80.0%, respectively, as compared to the control. The same promising activities were obtained on studying the anti-adherent effect of the tested bacteriophages on the adherence of bacterial cells to the surface of urinary catheter segments. They reduced the number of adherent cells to a range of 30.8-43.8% and eradicated the pre-adherent cells to a range of 48.2-71.1%, as compared to the control. Overall, the obtained promising antibiofilm activity makes these phages good candidates for application in preventing and treating biofilm associated Enterococcus faecalis infections.

Antioxidant, Antimicrobial Activities and Characterization of Polyphenol-Enriched Extract of Egyptian Celery (Apium graveolens L., Apiaceae) Aerial Parts via UPLC/ESI/TOF-MS.

Medicinal plant extracts are increasingly considered a major source of innovative medications and healthcare products. This study focused on preparing a polyphenol enriched water extract of Egyptian celery "Apium graveolens L., Apiaceae" aerial parts (TAE) in an endeavor to accentuate its antioxidant capacity as well as its antimicrobial activity. (TAE) of celery was partitioned against different organic solvents to yield dichloromethane (DCM), ethyl acetate (EAC), and butanol (BUOH) fractions. (TAE) and the organic fractions thereof besides the remaining mother liquor (ML) were all screened for their antioxidant capacity using various protocols viz. monitoring the reducing amplitudes for ferric ions (FRAP), and radical scavenging potentials of oxygen (ORAC), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and metal chelation assays. The examination procedure revealed both (TAE) extract and (DCM) fraction, to pertain the highest antioxidant potentials, where the IC50 of the (TAE) using ABTS and metal chelation assays were ca. 34.52 ± 3.25 and 246.6 ± 5.78 µg/mL, respectively. The (DCM) fraction recorded effective results using the FRAP, ORAC, and DPPH assays ca. 233.47 ± 15.14 and 1076 ± 25.73 µM Trolox equivalents/mg sample and an IC50 474.4 ± 19.8 µg/mL, respectively. Additionally, both (TAE) and (DCM) fraction exerted antimicrobial activities recording inhibition zones (mm) (13.4 ± 1.5) and (12.0 ± 1.0) against Staphylococcus aureus and (11.0 ± 1.2) and (10.0 ± 1.3) against Escherichia coli, respectively, with no anti-fungal activity. Minimum inhibitory concentration (MIC) of (TAE) and (DCM) fraction were 1250 and 2500 µg/mL, respectively. UPLC/ESI/TOF-MS unveiled the chemical profile of both (TAE) and (DCM) fraction to encompass a myriad of active polyphenolic constituents including phenylpropanoids, coumarins, apigenin, luteolin, and chrysoeriol conjugates.

Development of a specific troponin I detection system with enhanced immune sensitivity using a single monoclonal antibody.

Using an immunoassay in combination with surface plasmon fluorescence spectroscopy (SPFS), we report the rapid detection of troponin I, a valuable biomarker for diagnosis of myocardial infarction. We discuss the implementation of (i) direct, (ii) sandwich, and (iii) competitive assay formats, based on surface plasmon resonance and SPFS. To elucidate the results, we relate the experiments to orientation-dependent interaction of troponin I epitopes with respective immunoglobulin G antibodies. A limit of detection (LoD) of 19 pM, with 45 min readout time, was achieved using single monoclonal antibody that is specific for one epitope. The borderline between normal people and patients is 20 pM to 83 pM cTnI concentration, and upon the outbreak of acute myocardial infraction it can raise to 2 nM and levels at 20 nM for 6-8 days, therefore the achieved LoD covers most of the clinically relevant range. In addition, this system allows for the detection of troponin I using a single specific monoclonal antibody, which is highly beneficial in case of detection in real samples, where the protein has a complex form leading to hidden epitopes, thus paving the way towards a system that can improve early-stage screening of heart attacks.

Immuno-analytical approach and its application for cardiac disease marker detection.

Cardiac troponin-I is a promising diagnostic marker for cardiovascular diseases. Troponin-I immunoassays rely on monoclonal antibodies, while polyclonal antibodies, cheaper to manufacture, are uncommonly used. The current study established an immuno-analytical assay using a polyclonal antibody capable of mapping troponin-I antigenic determinant. Proteolytic digestion of troponin-I was performed. Antigenic determinant was assigned by separation of fragments using gel electrophoresis followed by Western blot and high-performance liquid chromatography followed by dot blot. The antigenic determinant region appeared within amino acid sequence 30-90. This robust procedure is suitable for early prognosis of diseases, stratification of patients, and possibly individualized therapy.

Thermoresponsive gels containing gold nanoparticles as smart antibacterial and wound healing agents.

Thermoresponsive gels containing gold nanoparticles (AuNPs) were prepared using Pluronic®127 alone (F1) and with hydroxypropyl methylcellulose (F2) at ratios of 15% w/w and 15:1% w/w, respectively. AuNPs were evaluated for particle size, zeta-potential, polydispersity index (PDI), morphology and XRD pattern. AuNP-containing thermoresponsive gels were investigated for their gelation temperature, gel strength, bio-adhesive force, viscosity, drug content, in vitro release and ex-vivo permeation, in addition to in vitro antibacterial activity against bacteria found in burn infections, Staphylococcus aureus. In vivo burn healing and antibacterial activities were also investigated and compared with those of a commercial product using burn-induced infected wounds in mice. Spherical AuNPs sized 28.9-37.65 nm displayed a surface plasmon resonance band at 522 nm, a PDI of 0.461, and a zeta potential of 34.8 mV with a negative surface charge. F1 and F2 showed gelation temperatures of 37.2 °C and 32.3 °C, bio-adhesive forces of 2.45 ± 0.52 and 4.76 ± 0.84 dyne/cm2, viscosities of 10,165 ± 1.54 and 14,213 ± 2.31 cP, and gel strengths between 7.4 and 10.3 sec, respectively. The in vitro release values of F1 and F2 were 100% and 98.03% after 6 h, with permeation flux values of (J1) 0.2974 ± 2.85 and (J2) 0.2649 ± 1.43 (µg/cm2·h), respectively. The formulations showed antibacterial activity with the highest values for wound healing properties, as shown in vivo and by histopathological studies. This study demonstrates that a smart AuNPs thermoresponsive gel was successful as an antibacterial and wound healing transdermal drug delivery system.

Mass spectrometric epitope mapping.

Mass spectrometric epitope mapping has become a versatile method to precisely determine a soluble antigen's partial structure that directly interacts with an antibody in solution. Typical lengths of investigated antigens have increased up to several 100 amino acids while experimentally determined epitope peptides have decreased in length to on average 10-15 amino acids. Since the early 1990s more and more sophisticated methods have been developed and have forwarded a bouquet of suitable approaches for epitope mapping with immobilized, temporarily immobilized, and free-floating antibodies. While up to now monoclonal antibodies have been mostly used in epitope mapping experiments, the applicability of polyclonal antibodies has been proven. The antibody's resistance towards enzymatic proteolysis has been of key importance for the two mostly applied methods: epitope excision and epitope extraction. Sample consumption has dropped to low pmol amounts on both, the antigen and the antibody. While adequate in-solution sample handling has been most important for successful epitope mapping, mass spectrometric analysis has been found the most suitable read-out method from early on. The rapidity by which mass spectrometric epitope mapping nowadays is executed outperforms all alternative methods. Thus, it can be asserted that mass spectrometric epitope mapping has reached a state of maturity, which allows it to be used in any mass spectrometry laboratory. After 25 years of constant and steady improvements, its application to clinical samples, for example, for patient characterization and stratification, is anticipated in the near future. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:229-241, 2018.

Evaluation of antibacterial activity and toxic metal removal of chemically synthesized magnetic iron oxide titanium coated nanoparticles and application in bacterial treatment.

Co-precipitation method was used for preparation of two types of iron oxide nanoparticles coated by titanium dioxide according to divalent salts used. The average size of iron oxide nanoparticles coated by titanium dioxide measured by particle size analyzer, ranged approximately between 20 nm and 100 nm with mean particle size of 60 nm. Characterization of the prepared nanoparticles was done by X-ray diffraction analysis and scanning electron microscope indicating the sole existence of inverse cubic spinel phase of magnetic iron oxide nanoparticles. Further, the antibacterial activity of two prepared iron oxide nanoparticles was evaluated against four pathogenic bacteria where both preparations showed promising antibacterial activities against Gram positive and Gram negative strains which offers a potential application in pharmaceutical and biomedical industries. The antibacterial activity showed high reduction percent after 30 min by 150 µg mL-1 of nanoparticles prepared. Also, high reduction percent was achieved for removal of iron and manganese ions from polluted water and good effect on decreasing chemical oxygen demand and biochemical oxygen demand concentrations with decreased percent of total nitrogen concentration.

Honey-based hydrogel: In vitro and comparative In vivo evaluation for burn wound healing.

Honey was used to treat wounds since ancient times till nowadays. The present study aimed at preparing a honey-based hydrogel and assay its antimicrobial properties and wound healing activity; in-vitro and in-vivo. Topical honey hydrogel formulations were prepared using three honey concentrations with gelling agents; chitosan and carbopol 934. The prepared formulae were evaluated for pH, spreadability, swelling index, in-vitro release and antimicrobial activity. The pH and spreadability were in the range of 4.3-6.8 and 5.7-8.6 cm, respectively. Chitosan-based hydrogel showed higher in-vitro honey release with diffusional exponent 'n ≤ 0.5 indicates Fickian diffusion mechanism. Hydrogel formulae were assessed for in-vitro antimicrobial activity using Disc Diffusion antibiotic sensitivity test against common burn infections bacteria; Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumonia and Streptococcus pyogenes. The 75% honey-chitosan hydrogel showed highest antimicrobial activity. This formula was tested for in-vivo burn healing using burn-induced wounds in mice. The formula was evaluated for burn healing and antibacterial activities compared to commercial product. 75% honey-chitosan hydrogel was found to possess highest healing rate of burns. The present study concludes that 75% honey-chitosan hydrogel possesses greater wound healing activity compared to commercial preparation and could be safely used as an effective natural topical wound healing treatment.

A novel strategy for the rapid preparation and isolation of intact immune complexes from peptide mixtures.

The development and application of a miniaturized affinity system for the preparation and release of intact immune complexes are demonstrated. Antibodies were reversibly affinity-adsorbed on pipette tips containing protein G´ and protein A, respectively. Antigen proteins were digested with proteases and peptide mixtures were exposed to attached antibodies; forming antibody-epitope complexes, that is, immune complexes. Elution with millimolar indole propionic acid (IPA)-containing buffers under neutral pH conditions allowed to effectively isolate the intact immune complexes in purified form. Size exclusion chromatography was performed to determine the integrity of the antibody-epitope complexes. Mass spectrometric analysis identified the epitope peptides in the respective SEC fractions. His-tag-containing recombinant human glucose-6-phosphate isomerase in combination with an anti-His-tag monoclonal antibody was instrumental to develop the method. Application was extended to the isolation of the intact antibody-epitope complex of a recombinant human tripartite motif 21 (rhTRIM21) auto-antigen in combination with a rabbit polyclonal anti-TRIM21 antibody. Peptide chip analysis showed that antibody-epitope binding of rhTRIM21 peptide antibody complexes was not affected by the presence of IPA in the elution buffer. By contrast, protein G´ showed an ion charge structure by electrospray mass spectrometry that resembled a denatured conformation when exposed to IPA-containing buffers. The advantages of this novel isolation strategy are low sample consumption and short experimental duration in addition to the direct and robust methodology that provides easy access to intact antibody-antigen complexes under neutral pH and low salt conditions for subsequent investigations.