Modulatory effects of Australian honeys on inflammation, oxidative stress and wound healing
Creators: name: Beiranvand, Soheila
Publisher: name: University of the Sunshine Coast, Queensland
Year: 2022
Subjects: chronic wound
oxidative stress
antioxidant
free radical
anti-inflammatory
physicochemical property
radical scavenging capacity
DPPH
Eucalyptus honey
non-Eucalyptus honey
phenolic acid
Flavonoid Scratch assay
Pharmacology and pharmaceutical sciences

description: Chronic wounds are those that do not heal in a predictable, ordered and timely fashion and are associated with oxidative stress. The morbidity and costs associated with chronic wounds emphasize the importance of an effective wound healing treatment. Oxidative stress is a condition caused by imbalance of free radicals and antioxidants in the body. Antioxidants act as free radical scavengers to prevent and repair damages caused by free radicals. Honey as a bioactive compound is highly valued by consumers as an alternative medicine for therapeutic purposes, particularly due to its antioxidant, anti-inflammatory and wound healing activities. The composition of honey depends mainly on the flowers, climate, geographical regions, and weather conditions. Australia is the fourth largest honey exporter worldwide which produces ~ 25000 tonnes of honey p.a. Australian flora and climate are distinctive, and the antioxidant activity of honey contributes to its phenolic acid and flavonoid content. Therefore, the work described in this study aimed to identify the physicochemical properties and radical scavenging capacity (RSC) of Australian honeys and their relationships with botanical and geographical origins, identify and quantify phenolic acids and flavonoid compounds in Australian non-Eucalyptus honeys and evaluate their potential for wound healing in cultured fibroblasts and keratinocytes. It was found that the botanical origin is a more important determinant of physicochemical properties and radical scavenging capacity than geographical origin. Using the kinetic model of 1,1-diphenyl-2 picrylhydrazyl radical (DPPH•) assay to address the limitation of single time point DPPH• assay led to identify two Eucalyptus honeys with very high antioxidant capacity namely, river red gum and grey ironbark honeys. Comparing the retention time (RT) and ultraviolet (UV) spectra of 62 phenolic standards to Australian non-Eucalyptus honeys in this study using high-performance liquid chromatography (HPLC) method found several phenolic acids, including (i) 4-Hydroxyphenylacetic acid (detected in L. polygalifolium and Eucryphia lucida honeys); (ii) p-Hydroxybenzoic acid (detected in L. polygalifolium honeys); (iii) Lumichrome (detected in Eucryphia lucida and L. liversidgeii).
description: Australian Eucalyptus honeys with the highest RSC, grey ironbark and river red gum honeys, as well as Tasmanian manuka honey were shown to stimulate interleukin (IL-6) production in cultured human fibroblasts in a time-dependant manner. Interestingly, grey ironbark honey was also able to stimulate IL-6 production in cultured human keratinocytes. However, Australian honeys with high potential antioxidant capacity did not stimulate the proliferation and migration of cultured human fibroblasts using the scratch assay wound healing model. The results of cell-based studies suggest that select Australian honeys may promote wound healing processes by stimulation of IL-6 production during the early stage of healing. This PhD research project represents an important first step in the determination of radical scavenging capacity and possible wound healing properties of Australian honeys, pending further investigations.