Effect of Iron and Hydrogen Peroxide Supplementation on the Total Phenols Content and Cytoxicity of Honey for MCF-7 Breast Cancer Cells

Abstract

Aims: To evaluate the effect of supplementation with iron (II/III) salts and/ or hydrogen peroxide on Manuka honey total phenols content (TPC) and the cytoxicity toward MCF-7 breast cancer cells. Study Design:  The study had an In Vitro design. Place and Duration of Study: Ulster University, School of Biomedical Sciences, between September 2017 and May 2018. Methodology: Manuka honey rated Unique Manuka Factor (UMF) 18+ was supplemented with 0.45 mM or 4.5 mM of iron (II/III) salts and/ or 1.2 mM hydrogen peroxide. Changes of TPC were monitored by the Folin-Ciocalteu method. Cytotoxicity was investigated using MCF-7 breast cancer cells and Sulforhodamine B (SRB) staining.  Results: Addition of low amounts of iron to honey and ageing for 120 hours led to significant losses of TPC (20.49 ± 1.24%) whilst adding 4.5 mM iron(II) / hydrogen peroxide  produced a rise (218.9 ± 2.6%) of TPC consistent with phenol hydroxylation. Manuka honey toxicity towards MCF-7 cells was increased after supplemented with iron salts and ageing by 120 hours compared to freshly prepared Manuka honey / iron (III) sample. The changes are discussed in relation to a Fenton reaction model. Conclusion: Manuka honey supplemented with iron and hydrogen peroxide showed decreases of TPC and increased cytotoxic effects towards MCF-7 breast cancer cells.