3rd September, 2012
Recent data suggests that ellagic acid and ellagitannins, a class of hydrolysable tannins found in some fruits and nuts, may have potential to ameliorate symptoms associated with inflammatory bowel diseases. Boysenberries, a hybrid Rubus berry, are amongst the best food sources of ellagitannins, although chestnuts and pomegranates also have high concentrations. Nutrigenomics NZ (NuNZ) is currently investigating the efficacy of boysenberries for promoting intestinal health. This research has the potential to provide the scientific validation necessary to support a value-added spin off for New Zealand, the largest producer and marketer of boysenberries worldwide, with annual sales of NZ$6-10 million.
NuNZ researchers have shown that boysenberry ellagitannins strongly inhibit a protein known as Janus-kinase-2 (JAK2). The role of JAK2 is to transmit signals from receptors on the cell surface to the nucleus. In certain genetically susceptible individuals JAK2 acquires a mutation which causes uncontrolled JAK2 activity. When the JAK2 mutation occurs in immune cells, this can lead to the development of Crohnâ€™s disease.
This finding led to the development by Harry Martin of a rapid, robotised assay to detect JAK2 inhibitors in foods and beverages. Combining this assay with Tony McGhieâ€™s high performance liquid chromatography (HPLC) analytical method which separated many different boysenberry compounds, it was possible to identify several active ellagitannins within a few hours. The ellagitannins were separated from the dark purple anthocyanins, which have different health benefits. These results are published in the journal Food & Function.
It remains to be seen whether the boysenberry compounds are able to damp down the excessive JAK2 activity in the digestive systems of Crohnâ€™s patients. Potential health benefits of boysenberry ellagitannins are being investigated by NuNZ PhD student Alana Srubar-Vernon in cell-model assays and animal models of inflammatory bowel diseases, and other NuNZ researchers have investigated their stability in food and beverage products.