20 research outputs found
Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens
Honey has potent activity against both antibiotic-sensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We investigated the kinetics of the killing of antibiotic-resistant bacteria by RS honey, the source for the production of Revamil® medical-grade honey, and we aimed to enhance the rapid bactericidal activity of RS honey by enrichment with its endogenous compounds or the addition of antimicrobial peptides (AMPs). RS honey killed antibiotic-resistant isolates of Pseudomonas aeruginosa, Staphylococcus epidermidis, Enterococcus faecium, and Burkholderia cepacia within 2 h, but lacked such rapid activity against methicillin-resistant S. aureus (MRSA) and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. It was not feasible to enhance the rapid activity of RS honey by enrichment with endogenous compounds, but RS honey enriched with 75 μM of the synthetic peptide Bactericidal Peptide 2 (BP2) showed rapid bactericidal activity against all species tested, including MRSA and ESBL E. coli, at up to 10–20-fold dilution. RS honey enriched with BP2 rapidly killed all bacteria tested and had a broader spectrum of bactericidal activity than either BP2 or honey alone
Two Major Medicinal Honeys Have Different Mechanisms of Bactericidal Activity
Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil® source (RS) honey and manuka honey, the sources of two major medical-grade honeys. RS honey killed Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa within 2 hours, whereas manuka honey had such rapid activity only against B. subtilis. After 24 hours of incubation, both honeys killed all tested bacteria, including methicillin-resistant Staphylococcus aureus, but manuka honey retained activity up to higher dilutions than RS honey. Bee defensin-1 and H2O2 were the major factors involved in rapid bactericidal activity of RS honey. These factors were absent in manuka honey, but this honey contained 44-fold higher concentrations of methylglyoxal than RS honey. Methylglyoxal was a major bactericidal factor in manuka honey, but after neutralization of this compound manuka honey retained bactericidal activity due to several unknown factors. RS and manuka honey have highly distinct compositions of bactericidal factors, resulting in large differences in bactericidal activity
Honey health benefits and uses in medicine
The generation of reactive oxygen species (ROS) and other free radicals during
metabolism is an essential and normal process that ideally is compensated through
the antioxidant system. However, due to many environmental, lifestyle, and pathological
situations, free radicals and oxidants can be produced in excess, resulting in
oxidative damage of biomolecules (e.g., lipids, proteins, and DNA). This plays a
major role in the development of chronic and degenerative illness such as cancer,
autoimmune disorders, aging, cataract, rheumatoid arthritis, cardiovascular, and
neurodegenerative diseases (Pham-Huy et al. 2008; Willcox et al. 2004). The human
body has several mechanisms to counteract oxidative stress by producing antioxidants, which are either naturally synthetized in situ, or externally supplied
through foods, and/or supplements (Pham-Huy et al. 2008).info:eu-repo/semantics/publishedVersio
The Antibacterial Activity of Honey Derived from Australian Flora
Chronic wound infections and antibiotic resistance are driving interest in
antimicrobial treatments that have generally been considered complementary,
including antimicrobially active honey. Australia has unique native flora and
produces honey with a wide range of different physicochemical properties. In
this study we surveyed 477 honey samples, derived from native and exotic plants
from various regions of Australia, for their antibacterial activity using an
established screening protocol. A level of activity considered potentially
therapeutically useful was found in 274 (57%) of the honey samples, with
exceptional activity seen in samples derived from marri (Corymbia
calophylla), jarrah (Eucalyptus marginata) and
jellybush (Leptospermum polygalifolium). In most cases the
antibacterial activity was attributable to hydrogen peroxide produced by the
bee-derived enzyme glucose oxidase. Non-hydrogen peroxide activity was detected
in 80 (16.8%) samples, and was most consistently seen in honey produced
from Leptospermum spp. Testing over time found the hydrogen
peroxide-dependent activity in honey decreased, in some cases by 100%,
and this activity was more stable at 4°C than at 25°C. In contrast, the
non-hydrogen peroxide activity of Leptospermum honey samples
increased, and this was greatest in samples stored at 25°C. The stability of
non-peroxide activity from other honeys was more variable, suggesting this
activity may have a different cause. We conclude that many Australian honeys
have clinical potential, and that further studies into the composition and
stability of their active constituents are warranted