Anti-proliferative effects induced by New Zealand honey in colorectal cancer
Chan, Chi Yuen
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Colorectal cancer is responsible for nearly a third of all deaths within New Zealand and has contributed 15% of worldwide malignancies. At present, colorectal cancer treatment is inadequate, although with developing treatments, such as the front-line drug, oxaliplatin, there are new options for those battling the disease. Still, as with other cancer treatment drugs, the benefit of oxaliplatin is marginal, especially depending on the stage of the disease. Cancer treatment drugs come with many toxic side effects, which can potentially include (but are not limited to): neurotoxicity, nausea, vomiting, diarrhoea, neutropenia, ototoxicity, extravasation and hypokalaemia. Therefore, developing new types of treatment with less harmful side effects has always be the main goal through medical history. Previous studies suggested honey could be a potential candidate due to its antioxidant effect, anti-inflammatory effect and possibly anti-tumour effect. The number of honey anti-tumour research projects are increasing and quite a lot of them have indicated effective reduction in cancerous cells. Although the anti-tumour effect of honey is limited to in vivo studies, a lot of researchers have hypothesised that using honey as a treatment for cancer could provide an outcome with less side effects as a result. Existing drug treatments for colon cancer are associated with toxic side effects, while the potential for less side effects from using honey against colon cancer is promising. In this respect, honey treatments would rival those offered with existing drugs (e.g., Avastin, Bevacizumab, oxaliplatin, etc.). We hypothesize that honey induces an anti-proliferative effect through apoptotic pathways in colon cancer cell lines. The primary objective of this research was to investigate the anti-proliferative effects of Manuka honey and Thyme honey on two colorectal cancer cell lines by using MTT assays. The secondary objective would be to measure the apoptotic properties of these honey treatments by flow cytometry. Two types of colon cancer cell lines were used in this study: LoVo (CCL-229) and WiDr (CCL-218) cell lines. Anti-proliferative effects were determined by 24 hour, 48 hour and 72 hour MTT cell viability assay. Oxaliplatin was used as a positive control in this study, and both cell lines were treated with 0.5%, 1.25%, 2.5% and 5% of Vitabeez’s honey solution. The honey solution was prepared by mixing RPMI 1640 cell culture medium with honey to achieve a similar osmolarity as found in the human body. The absorbance values were measured and the cell viability (%) was determined. The anti-proliferative effect seemed to be increased when the honey concentration was increased, as well as with increased time of treatment. Therefore, according to our statistically significant results, the tested honey show time-dependent and concentration-dependent anti-proliferative activity against the tested human colon cancer cells lines. The secondary objective involved in this study was to determine the pro-apoptotic activity of tested honey in LoVo and WiDr cells. An increased apoptotic activity was observed when the honey concentration was increased at designated time period. Analysis for apoptotic activity indicated greatest numbers of cell death associated with treatment using the 2.5% honey solution.