26.3.09

Bird flu antidote found in W Ghats

Shikimic acid, the most vital ingredient used to make Oseltamivir, (Tamiflu) the only known drug to combat the deadly bird flu, has been found in trees in the Western Ghats. A team of scientists from University of Agricultural Sciences, Bangalore, has found at least seven plant species that yielded shikimic acid from the Western Ghat forests, one of the world’s 10 hottest biodiversity hotspots. Reporting their finding in the latest issue of medical journal Current Science, the scientists said they scanned through 210 plant species to shortlist “a few promising species whose leaves yielded shikimic acid level higher than 1%”. Currently, the majority of the acid’s global availability is met by China. The fruits of the Chinese star anise tree contain between 2% to 7% of the acid, the highest reported estimate from plants. But the tree attains seed-bearing stage after six years of growth, making it unlikely that the growing demand for the acid would be met by the single source alone. Interestingly, the trees discovered by Indian scientists have yielded 1%- 5.02% of shikimic acid, with a species called Araucaria Excelsa yielding almost 5.02%. The significant advantage of these new sources is that the estimates are from leaves and not fruits. In the face of the growing demand for shikimic acid, it is imperative that newer sources are identified, the scientists said. It is estimated that nearly twothirds of the requirement is sourced from plants while one-third is obtained from genetically engineered E Coli. The team said, “The leads presented here appear more promising than others. In few of these species, the estimates are comparable to those reported from star anise. As the estimates are from leaves, the sheer volume of the biomass offered by leaves would render it economically feasible. This finding of a new source of shikimic acid can potentially be used to meet the emerging needs of the domestic and international markets.”
Tamiflu, the drug which blocks the replication of the virus, is being stockpiled by most countries as a precautionary measure in case of an outbreak of bird flu among humans. So, the price of shikimic acid has skyrocketed. Pharma companies in India say the acid, which used to cost $40 a kg earlier, now costs around $1,000 per kg.

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