Background – Colorectal cancer (CRC) is the second ranked cause of cancer related death in Australia. A healthy lifestyle based on a good diet is the most attractive preventative strategy to fight this disease. Dietary fruits, vegetables, legumes and cereals are recommended for the prevention of CRC development. It is desirable to know which particular foods posses specific anticancer properties. From our research, several plant-derived products with anticancer properties have been identified and found to protect at different stages of the complex process of carcinogenesis.
Objective – The objective was to identify dietary plant sources with anti-proliferative and apoptotic properties against HT-29 colon cancer cells.
Design – Aqueous-ethanolic extracts of edible part of plants, nuts and herbs were tested in exponentially growing HT-29 cells in 96 well plates using the cell titre blue (CTB) assay. Lead samples with anti-proliferative activity were then further tested for their specific effects on apoptosis, histone deacetylase (HDAC) activity, cell cycle phase, and expression of cyclooxygenases (COX) and enzymes implicated in CRC such as quinone reductase and glutathione synthase transferase (GST).
Outcomes – Salicylate at 10 mM inhibited the growth of HT-29 cells up to 55 % with no effect on apoptosis, conversely butyrate at 10 mM inhibited the growth of HT-29 cells at about 30 % and induced apoptosis up to 25%. We found several plant genera including rosemary, chives, bay leaves, coriander, basil, cardamom and cloves demonstrated anti-proliferative and apoptotic activity comparable to salicylate and butyrate and altered activity and expression of key enzymes linked to CRC development.
Conclusion – We have identified leads from food extracts with potential anticancer properties. We intend to further validate these lead extracts in animal models of CRC to develop functional foods and nutraceutical products that might prevent the development of human CRC.