The first extracts from papaya leaves grown at a Northland research orchard are now part of a clinical study at universities in the UK and in Asia in a project, spearheaded by Queenstown based company Fuller Young International.
According to Managing director Raymond Young, research and development within New Zealand has been supported by Crown institutes, Plant and Food Research and Auckland based Callaghan Innovation. He added that papaya had long been used in traditional herbal remedies in tropical areas for illnesses associated with the mosquito related virus, plus general age related illnesses. But the origin was a request from his Singapore-based daughter who was concerned about the risks to her children from the dengue virus.
Young said no one really knew what was in the leaf that made it an effective treatment for the dengue virus, so they set about looking into extracts of leaf and how to make it more efficient. However, said once they found out what it was, they began looking at methods of manufacturing, although they soon discovered papaya was hard to obtain.
After talking with Plant and Food Research, the company grew its first variety called Wakatengu, which was planted out in the spring and fruit and leaves harvested before winter. The 1 ha plantation holds about 700 trees, similar in scale to the operation in Japan, but where the winters were much colder and the summers hotter. The use of high-potency organic fertiliser, mainly chicken manure, had yielded good results, Young said.
Rnz.co.nz quoted Young as saying: "It was very successful. We adjusted the growing method and got the same result. We harvested the leaf and, working with Callaghan, we worked on extracting the active ingredient."
He found it interesting that the compounds believed to be beneficial in treating the dengue virus were more potent in the leaves of the crop grown in New Zealand than that grown in Japan.