Tamiflu demand outstripped production in 2005 owing in part to a shortage of shikimic acid, which is currently harvested from star anise fruit in China and produced in genetically modified Escherichia coli.
Roche has now managed to increase production to above the current levels of demand but the fear remains that in the event of a pandemic a shortage of shikimic acid would again become a factor.
Consequently researchers from Bangalore in Southern India began bioprospecting in the Western Ghats in an attempt to find an alternative, more easily cultivable source of shikimic acid.
The research has now been published in Current Science, with the results suggesting that some plants in the region could provide viable alternative sources of shikimic acid.
Calophyllum apetalum and Araucaria excelsa were identified by the researchers as containing four to five percent shikimic acid by dry weight, which is comparable to the two to seven per cent found in star anise fruit.
However, in an interview with The Indian Telegraph Ramanan Uma Shaanker, one of the study’s authors, revealed that the names of two more promising plants had been withheld after discussions with the Indian Department of Biotechnology.
Shaanker said: “These species may provide an opportunity for India to break China’s monopoly on shikimic acid but we thought it would be best to keep the identity of the trees secret to avoid unplanned exploitation.”
Further work is now needed to asses the extraction process and the distribution of the potential shikimic acid sources to establish their economic viability.
One big advantage the Indian plants have over the currently established Chinese source is that the shikimic acid levels were detected in leaves, unlike the star anise that requires the fruit to be harvested.
Star anise fruits have been shown to contain higher levels of shikimic acid than the Indian plants but the use of leaves offers far greater biomass to harvest, which could make it more economically attractive.
The full research paper can be found here.