Assay of the antioxidant capacity of foods using an iron(II)-catalysed lipid peroxidation model for greater nutritional relevance

Brangoulo, Hélène L.; Molan, Peter C.

doi:10.1016/j.foodchem.2010.09.099

Cited by 15 publications

(5 citation statements)

References 31 publications

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“…The strong iron (II) chelating activity we observe for MH may result from one or more of the antibacterial phenolics present in MH (Weston et al ). Iron‐chelating activity has been attributed to the phenolic fraction of Beech Honeydew honey from New Zealand, but the exact molecules responsible have yet to be identified (Brangoulo and Molan ). Like MH, Beech Honeydew honey has been shown to have high levels of non‐peroxide antimicrobial activity.…”

Section: Discussionmentioning

confidence: 99%

Manuka honey chelates iron and impacts iron regulation in key bacterial pathogens

et al. 2019

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Aim The aim of this study was to test the hypothesis that Manuka honey (MH) chelates iron and promotes an iron‐limiting environment, which contributes to its antimicrobial activity. Methods and Results Employing a ferrozine‐based assay, we observed that MH is an iron chelator that depletes iron from solution. Siderophores are small molecules that bind ferric iron (III) with high affinity and their levels are upregulated by bacteria under iron‐limiting conditions. We demonstrated by quantitating siderophore production that Escherichia coli and Pseudomonas aeruginosa treated with MH sub‐minimum inhibitory concentrations (sub‐MIC) experience an iron‐limiting environment and increase siderophore production. In addition, supplementation with ferrous iron (II) significantly increased growth of E. coli, Staphylococcus aureus and P. aeruginosa cultured at their MH MIC above that observed in nonsupplemented controls. By contrast, supplementation with ferric iron (III) significantly increased growth for only E. coli and P. aeruginosa, above their nonsupplemented controls. Conclusions Manuka honey chelates iron, thereby generating an iron‐limiting environment for E. coli and P. aeruginosa, and to a lesser extent S. aureus, which contributes to its antimicrobial properties. Significance and Impact of the Study Our work demonstrates that MH‐induced iron chelation is an antimicrobial mechanism that differentially impacts the bacterial species tested here. Iron chelation affects multiple diverse physiological processes in bacteria and would contribute to the lack of bacterial resistance to MH. Iron metabolism is tightly regulated; bacteria require this essential nutrient for survival, but in excess it is toxic. Additional exploration of MH’s iron chelation mechanism will facilitate its future use in mainstream medicine.

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Section: Discussionmentioning

confidence: 99%

Manuka honey chelates iron and impacts iron regulation in key bacterial pathogens

et al. 2019

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“…The free radical scavenging activity was determined according to the method of Baltrusaityte et al [ 57 ] with some modifications reported by Brangoulo et al [ 58 ]. The ABTS•+ free radical solution was prepared (final concentration-7 mM/L) with potassium persulphate (final concentration-2.45 mM/L) and left to react for 16 h to form the stable ABTS•+ radical cation.…”

Section: Methodsmentioning

confidence: 99%

Characterization of Physico-Chemical Properties and Antioxidant Capacities of Bioactive Honey Produced from Australian Grown Agastache rugosa and its Correlation with Colour and Poly-Phenol Content

et al. 2018

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The antioxidant and antimicrobial components of honey vary based on sourced of nectar. Medicinal plants with the therapeutic value have potential to produce honey with greater bioactivity. The aim of the present study was to characterize the physico-chemical and antioxidant capacities of Agastache honey produced from Agastache rugosa and compare them with other popular commercial honeys sold in Australia. The total phenolics, total flavonoids, moisture content, colour, pH, protein content and antioxidant capacity were evaluated for Agastache, Manuka, Jelly bush, Tea tree, Super manuka and Jarrah honeys. The results reveal that the moisture content ranged from 17–21%, pH ranged from 3.8–4.3 and estimated protein content ranged from 900–2200 µg/g. The DPPH•, ABTS•+, ORAC and FRAP methods were used to measure the antioxidant capacity of the honey samples. The DPPH• % inhibition, ABTS•+, ORAC and FRAP values for Agastache honey were 9.85 (±1.98 µmol TE/g), 26.88 (±0.32 µmol TE/g), 19.78 (±1.1 µmol TE/g) and 3.61 (±0.02 µmol TE/g) whereas the highest antioxidant capacity values obtained were 18.69 (±0.9 µmol TE/g), 30.72 (±0.27 µmol TE/g), 26.95 (±0.9 µmol TE/g) and 3.68 (±0.04 µmol TE/g), respectively. There was a positive correlation between colour, total phenolic content and DPPH• scavenging activity for most of the honeys except Tea tree honey. However, there was no clear correlation with ABTS•+, ORAC and FRAP values. The measured antioxidant capacity of samples varied with the assays used. The DPPH• assay clearly indicated that the phenolic compounds contribute to the scavenging activity of the honeys. Nevertheless, all assays confirm that Agastache honey has significant antioxidant capacity. Therefore, Agastache honey can be important to human nutrition and health.

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“…Each assay was carried out in triplicate. This method follows closely that used by previous workers [16]. The inhibitory activity was calculated as for the DPPH assay.…”

Section: Abts Radical Scavenging Assaymentioning

confidence: 99%

Radical Scavenging and Antioxidant Activities of Essential Oil Components – An Experimental and Computational Investigation

Sharopov

Wink

Setzer

2015

Natural Product Communications

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The antioxidant activities of eighteen different essential oil components have been determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicalscavenging assay, the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation assay, and the ferric reducing antioxidant power (FRAP) assay. The phenolic compounds, carvacrol, thymol, and eugenol, showed the best antioxidant activities, while camphor, menthol, and menthone were the least active. The structural and electronic properties of the essential oil components were assessed using density functional theory (DFT) at the B3LYP/6-311++G** level. Correlations between calculated electronic properties and antioxidant activities were generally poor, but bond-dissociation energies (BDEs) seem to correlate with DPPH radical-scavenging activities, and the ferric reducing antioxidant power (FRAP) assay correlated with vertical ionization potentials calculated at the Hartree-Fock/6-311++G** level.

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Assay of the antioxidant capacity of foods using an iron(II)-catalysed lipid peroxidation model for greater nutritional relevance

Cited by 15 publications

References 31 publications

Manuka honey chelates iron and impacts iron regulation in key bacterial pathogens

Manuka honey chelates iron and impacts iron regulation in key bacterial pathogens

Characterization of Physico-Chemical Properties and Antioxidant Capacities of Bioactive Honey Produced from Australian Grown Agastache rugosa and its Correlation with Colour and Poly-Phenol Content

Radical Scavenging and Antioxidant Activities of Essential Oil Components – An Experimental and Computational Investigation

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