scholarly journals Antibacterial Activity of Different Blossom Honeys: New Findings

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1573 ◽  
Author(s):  
Marcela Bucekova ◽  
Lucia Jardekova ◽  
Valeria Juricova ◽  
Veronika Bugarova ◽  
Gabriele Di Marco ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Antibacterial Activity ◽  
The Other ◽  
Proteinase K ◽  
Antibacterial Efficacy ◽  
Total Polyphenols ◽  
Bioactive Substances ◽  
New Findings ◽  
Bactericidal Activities

Antibacterial activity is the most investigated biological property of honey. The goal of this study was to evaluate the antibacterial activity of 57 Slovak blossom honeys against Staphylococcus aureus and Pseudomonas aeruginosa and investigate the role of several bioactive substances in antibacterial action of honeys. Inhibitory and bactericidal activities of honeys were studied to determine the minimum inhibitory and bactericidal concentrations. The contents of glucose oxidase (GOX) enzyme, hydrogen peroxide (H2O2), and total polyphenols (TP) were determined in honeys. We found that honey samples showed different antibacterial efficacy against the tested bacteria as follows: wildflower honeys > acacia honeys > rapeseed honeys. Overall antibacterial activity of the honeys was statistically-significantly correlated with the contents of H2O2 and TP in honeys. A strong correlation was found between the H2O2 and TP content. On the other hand, no correlation was found between the content of GOX and level of H2O2. Antibacterial activity of 12 selected honeys was markedly reduced by treatment with catalase, but it remained relatively stable after inactivation of GOX with proteinase-K digestion. Obtained results suggest that the antibacterial activity of blossom honeys is mainly mediated by H2O2 levels present in honeys which are affected mainly by polyphenolic substances and not directly by GOX content.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

scholarly journals Effect of Hydrogen Peroxide on the Antibacterial Substantivity of Chlorhexidine

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Shahriar Shahriari ◽  
Zahed Mohammadi ◽  
Mohammadi Mehdi Mokhtari ◽  
Rasoul Yousefi
Keyword(s):  
Hydrogen Peroxide ◽  
Antibacterial Activity ◽  
Enterococcus Faecalis ◽  
Time Lapse ◽  
Positive Control ◽  
Negative Control ◽  
The Other ◽  
Time Period ◽  
Colony Forming Units

The purpose of thisin vitrostudy was to assess the effect of hydrogen peroxide on the antibacterial substantivity of chlorhexidine (CHX). Seventy-five dentine tubes prepared from human maxillary central and lateral incisor teeth were used. After contamination withEnterococcus faecalisfor 14 days, the specimens were divided into five groups as follows: CHX, H2O2, CHX + H2O2, infected dentine tubes (positive control), and sterile dentine tubes (negative control). Dentine chips were collected with round burs into tryptic soy broth, and after culturing, the number of colony-forming units (CFU) was counted. The number of CFU was minimum in the first cultures in all experimental groups, and the results obtained were significantly different from each other at any time period (). At the first culture, the number of CFU in the CHX + H2O2group was lower than other two groups. At the other experimental periods, the CHX group showed the most effective antibacterial action (). Hydrogen peroxide group showed the worst result at all periods. In each group, the number of CFU increased significantly by time lapse (). In conclusion, H2O2had no additive effect on the residual antibacterial activity of CHX.

Post-Zionist Critique on Israel and the Palestinians: Part I: The Academic Debate

1997 ◽  
Vol 26 (2) ◽  
pp. 29-41 ◽  
Author(s):  
Ilan Pappe
Keyword(s):  
The Other ◽  
Israeli Society ◽  
Cultural Discourse ◽  
Economic Changes ◽  
New Findings ◽  
Academic Debate

This three-part article describes changes in how Israelis-scholars, writers, poets, film makers, and others on Israel's cultural scene-view themselves and the "Other." Part I presents the scholarly debate on Israel's past and present that laid the groundwork for the transformation of the cultural discourse described in the second and third parts. The debate, launched by new findings in the Israeli archives and encouraged by an ideology critical of Zionism, also was influenced by sociopolitical and economic changes in Israeli society in the wake of the October 1973 war. The various aspects of the post-Zionist critique-the challenge by the "new historians" and "critical sociologists" not only of the Zionist interpretation but also of the role of Israeli academia in providing the scholarly underpinnings of this interpretation-are examined.

The role of hydrogen peroxide in the antibacterial activity of different floral honeys

2019 ◽  
Vol 245 (12) ◽  
pp. 2739-2744 ◽  
Author(s):  
Jarmila Farkasovska ◽  
Veronika Bugarova ◽  
Jana Godocikova ◽  
Viktor Majtan ◽  
Juraj Majtan
Keyword(s):  
Hydrogen Peroxide ◽  
Antibacterial Activity

Synthesis AgNPs in Starch Solution by Green Method for New Medical Drugs

2020 ◽  
Vol 1002 ◽  
pp. 311-318
Author(s):  
Azhar J. Bohan ◽  
Duha S. Ahmed ◽  
Ghaed K. Salman
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Soluble Starch ◽  
The Other ◽  
Capping Agent ◽  
Dmso Solution ◽  
Starch Solution ◽  
Green Method ◽  
Nanoparticles Synthesis

Work represents the silver nanoparticles synthesis using green method by adding soluble starch in DMSO solution. The resulting AgNPs-based starch was noted via changing the color from yellow to brownish in aqueous DMSO solution in dark place due to the role of starch in the Ag ions reduction to AgNPs as capping agent in DMSO solvent at temperature 60°C. Then, the AgNPs development was characterized via the (UV-Vis) spectrophotometer. The morphology, structure and polydispersion of AgNPs were determined by using FESEM, XRD and Zeta analyzer, respectively which improved the role of starch in the formation of spherical and flower shapes of AgNPs. Moreover, the antibacterial activity of AgNPs-based starch revealed a strong effect against the positive bacteria than the negative bacteria as compared with the other antibiotic. Besides, these results suggest that the AgNPs prepared by green method can be utilized as efficient antimicrobial agent in the fields of medicine and represented the opportunities for the formation of safe and friendly AgNPs.

scholarly journals Anti-biofilm effects and characterisation of the hydrogen peroxide activity of a range of Western Australian honeys compared to Manuka and multifloral honeys

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Azhar Sindi ◽  
Moses Van Bawi Chawn ◽  
Magda Escorcia Hernandez ◽  
Kathryn Green ◽  
Md Khairul Islam ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Antibacterial Activity ◽  
Outer Membrane ◽  
Eucalyptus Marginata ◽  
Gram Negative ◽  
Infected Wounds ◽  
Endemic Flora ◽  
Western Australian ◽  
Global Growth

AbstractThe antibacterial activity of honeys derived from the endemic flora of the southwest corner of Western Australia, including the trees Jarrah (Eucalyptus marginata) and Marri (Corymbia calophylla), remains largely unexplored. Investigation of these honeys showed minimum inhibitory concentrations (MICs) of 6.7–28.0% (w/v) against Gram positive and negative bacteria. Honey solutions showed enhanced antibacterial activity after hydrogen peroxide was allowed to accumulate prior to testing, with a mean MIC after accumulation of 14.3% compared to 17.4% before accumulation. Antibacterial activity was reduced after treatment with catalase enzyme, with a mean MIC of 29.4% with catalase compared to 15.2% without catalase. Tests investigating the role of the Gram negative outer membrane in honey susceptibility revealed increases in activity after destabilisation of the outer membrane. Honeys reduced both the formation of biofilm and the production of bacterial pigments, which are both regulated by quorum sensing. However, these reductions were closely correlated with global growth inhibition. Honey applied to existing biofilms resulted in decreased metabolic activity and minor decreases in viability. These results enhance our understanding of the mechanisms of antibacterial action of Jarrah and Marri honeys, and provide further support for the use of honey in the treatment of infected wounds.

scholarly journals Re-Examining the Role of Hydrogen Peroxide in Bacteriostatic and Bactericidal Activities of Honey

2011 ◽  
Vol 2 ◽  
Author(s):  
Katrina Brudzynski ◽  
Kamal Abubaker ◽  
Martin Laurent ◽  
Alan Castle
Keyword(s):  
Hydrogen Peroxide ◽  
Bactericidal Activities

Role of capping agents in controlling silver nanoparticles size, antibacterial activity and potential application as optical hydrogen peroxide sensor

RSC Advances ◽  
2016 ◽  
Vol 6 (42) ◽  
pp. 36171-36179 ◽  
Author(s):  
B. Ajitha ◽  
Y. Ashok Kumar Reddy ◽  
P. Sreedhara Reddy ◽  
Hwan-Jin Jeon ◽  
Chi Won Ahn
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Catalytic Reaction ◽  
Potential Application ◽  
Capping Agents ◽  
Optical Absorbance ◽  
Hydrogen Peroxide Sensor ◽  
Absorbance Spectra

Catalytic reaction between PVA-capped AgNPs and hydrogen peroxide, and the corresponding LSPR optical absorbance spectra as a function of time.

scholarly journals Accumulation of polyphenols and flavonoids in Atriplex canescens (Pursh) Nutt stressed by heavy metals (zinc, lead and cadmium)

2020 ◽  
Vol 16 (3) ◽  
pp. 334-337
Author(s):  
Khedim Ikram ◽  
Reguieg Yssaad Houcine Abdelhakim ◽  
Bülent Topcuoglu ◽  
Osmane Badiaa ◽  
Tadjouri Houria
Keyword(s):  
Oxidative Stress ◽  
Heavy Metals ◽  
Secondary Metabolites ◽  
Dry Weight ◽  
The Other ◽  
Atriplex Canescens ◽  
Total Polyphenols ◽  
Lead And Cadmium ◽  
Cadmium Lead

Pollution of the environment and soils by heavy metals is one of the major problems of our time. Our study was to determine the effect of five doses for : zinc, lead and cadmium (0, 2500, 5000, 7500, and 10000 ppm) applied to the Atriplex canescens after 60 days for two weeks. The results showed an increase in the total polyphenols and flavonoids, depending on the increasing concentration of heavy metals at the leaf and root levels. The leaves have total polyphenols and flavonoids higher than those of the roots. The highest levels of total polyphenols and flavonoids in the leaves (3.47 mg EAG/ gdry weight of total polyphenols and 3.70 mg EQ/g dry weight of flavonoids) were obtained at a dose of 10000 ppm (cadmium, lead) respectively. On the other hand, the highest levels of total polyphenols and flavonoids in the roots were obtained at the metallic dose of 10000 ppm for cadmium (3.38 mg EAG/ gdry weight of total polyphenols and 0.61 mg EQ/g dry weight of flavonoids). These results also underlined the important role of secondary metabolites (total polyphenols and flavonoids) in the defense against oxidative stress caused by metallic stress.

Plasma Levels of Protein S, Protein C, and Factor X: Effects of Sex, Hormonal State and Age

1995 ◽  
Vol 74 (05) ◽  
pp. 1271-1275 ◽  
Author(s):  
C M A Henkens ◽  
V J J Bom ◽  
W van der Schaaf ◽  
P M Pelsma ◽  
C Th Smit Sibinga ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Postmenopausal Women ◽  
Protein C ◽  
Blood Donors ◽  
Premenopausal Women ◽  
Protein S ◽  
The Other ◽  
Factor X ◽  
Normal Ranges

SummaryWe measured total and free protein S (PS), protein C (PC) and factor X (FX) in 393 healthy blood donors to assess differences in relation to sex, hormonal state and age. All measured proteins were lower in women as compared to men, as were levels in premenopausal women as compared to postmenopausal women. Multiple regression analysis showed that both age and subgroup (men, pre- and postmenopausal women) were of significance for the levels of total and free PS and PC, the subgroup effect being caused by the differences between the premenopausal women and the other groups. This indicates a role of sex-hormones, most likely estrogens, in the regulation of levels of pro- and anticoagulant factors under physiologic conditions. These differences should be taken into account in daily clinical practice and may necessitate different normal ranges for men, pre- and postmenopausal women.

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