US cancer fighters seek Himalayan tree
THE Himalayan yew Taxus baccata is in the news. Researchers at the University of Kansas have found that the yew contains the anti-cancer drug, taxol, in sufficient quantities for it to replace its cousin, the Pacific yew. Indian botanists fear that the graceful tree may become gradually extinct.
American researchers have made arrangements for "tonnage quantities" of the leaves to be supplied to them bv an unidentified firm here. A longterm supply contract is also being negotiated.
The efficacy of taxol in the treatinent of ovarian and breast cancers was noted in the 1960s, but it is only now that researchers have discovered that the Himalayan strain will yield "large enough" quantities of the drug. Sixty pounds of bark from the Pacific yew is needed to produce enough taxol to treat just one patient.
American researchers as well as Bristol-Myers Squibb and Co, a US pharmaceutical firm, were previously extracting taxol from the bark of the Pacific yew. The tree was stripped off its bark in autumn and left to die a slow death.
Now, the widespread concern that the yew would eventually become extinct in North America is forcing them to look for alternatives. An American environmentalist in the Earth Island journal asks, "Must a tree become extinct, so that cancer victims may live?"
US researchers claim that the Himalayan tree would not be affected as the taxol would be extracted from its leaves. However, Virendra Kumar, head of the department of botany at the Zakir Hussain College, New Delhi, does not agree. "Removing the leaves of the Himalayan yew would have fatal effects," insists Kumar, "for it is the leaves that produce food for the tree through photosynthesis."
"The tree has to produce food for an entire year in just about a month. The rest of the year, there's frost in the Himalayan region," explains Kumar. "We do not know anything about this," claims S C Sharma, joint director (wildlife) at the ministry of environment. Taxus baccata is not included in the ministry's list of endangered plant species, &o licence or permission is necessary to obtain samples, or export parts of the tree. Laments Kumar;'our medicinal plants are being exported to the industrialised nations in such large quantities that many of them are already extinct."