Manuka Honey-induced Cytotoxicity against MCF7 Breast Cancer Cells is Correlated to Total Phenol Content and Antioxidant Power
I. Portokalakis
Faculty of Life and Health Sciences, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
H. I. Mohd Yusof
Faculty of Life and Health Sciences, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
D. F. Ghanotakis
Department of Chemistry, University of Crete, Voutes-Heraklion, Crete, 70013, Greece
P. Singh Nigam
Faculty of Life and Health Sciences, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
R. Owusu-Apenten *
Faculty of Life and Health Sciences, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
*Author to whom correspondence should be addressed.
Abstract
Aims: To investigate the relations between total polyphenols content, antioxidant power and Manuka honey cytotoxicity towards MCF-7 cells.
Study Design: In vitro study.
Place and Duration of Study: Department of Chemistry, University of Crete in partnership with the School of Biomedical Sciences, Ulster University, 09/ 2014 – 09/ 2015.
Methodology: Manuka honey (UMF 5+,10+, 15+ and 18+) were examined for total phenols content using the Folin-Ciocalteu method with results expressed as mg gallic acid equivalents per kg honey (mg GAE/kg). Antioxidant power was evaluated using the Ferric Reducing Antioxidant Power “FRAP” method and expressed as mg GAE/kg. Honey cytotoxicity was examined with MCF-7 breast cancer cells cultured with RPMI 1640 supplemented with charcoals stripped serum and viability was monitored using the MTT assay.
Results: The total phenols content for Manuka honey ranged from 1367±152 mg GAE/kg for UMF 5+ honey to 2358 ±79 mg GAE/ kg for UMF 18+ honey. The antioxidant power for Manuka honey ranged from 170±22 mg GAE/kg for UMF 5+ honey rising to 266±21 mg GAE/kg for UMF 18+ honey. Manuka honey showed dose-dependent cytotoxicity towards MCF-7 cells after 24 hrs. treatment. The concentration of honey which produces 50% inhibitory activity (IC50) ranged from 4.7% (w/v) for UMF 5+ honey to 2.2% (w/v) for UMF 18+ honey. The cytotoxicity of Manuka honey was highly correlated with, values for the total phenols content (R2=0.99) and antioxidant power (R2=0.95) of Manuka.
Conclusion: Manuka honey is cytotoxic to MCF-7 breast cancer cells in vitro and the effects are correlated with the total phenols content and antioxidant power.
Keywords: Manuka honey, MCF-7, breast cancer, antioxidant power, anticancer action, polyphenols