Rare, valuable tree faces rail line threat

Much of the current worldwide supply of the rare tree comes from China

A rare tree known for its anti-cancer properties and a vital component of the international pharmaceutical market worth Rs 21,000 cr annually could be imperiled by the proposed Hubballi-Ankola railway line in the Western Ghats, scientists said.

The tree, nothapodytes nimmoniana, is known for its concentration of camptothecin (CPT), an indole alkaloid known for its anti-cancer properties. According to the published international literature, CPT displays “remarkable” anti-cancer activity in preliminary clinical trials, especially against breast, ovarian, colon, lung, and stomach cancers.

Much of the current worldwide supply of camptothecin comes from China, where it is harvested from the bark and stem of the camptotheca acuminata, a tree native to the Himalayan plains.

However, in 2011, Er. Hemanta R Naik, a published scientist whose research within the Western Ghats spans 30 years, and scientists from IIT-Madras and the University of Purdue in the US published a paper in the journal of the Royal Society of Chemistry, showing a high presence of CPT in nothapodytes nimmoniana.

Veteran Field Botanist Dr Kaliyamoorthy Ravikumar described the tree species as being abundant in specific localities but in the “vulnerable” red category. “One of these clusters is in the Kali Tiger reserve, including in the area where the proposed railway line is set to go through,” said Naik.

He added that protection of the tree’s natural habitat is important because studies have shown that its CPT content reduces when grown in controlled settings outside the Ghats.

“A trial in GKVK found an 80% reduction in CPT content when the tree was grown on campus. It requires the presence of certain other plants and a fungus also found in the Western Ghats,” said Naik.

Some commercial extraction of CPT is said to be already ongoing from nothapodytes nimmoniana trees in the Western Ghats, much of it ad hoc.

"Local tribal people are paid about Rs 150-200 per day to extract the bark of the tree. When it reaches Mumbai, it is turned into a powder form and sells for Rs 15,000 per kg,” he said, explaining that roughly 1,000 kilos of bark is required to extract about 1 milligram of CPT.

According to a report in Elsevier, there is a demand for one tonne of crude CPT extract per year worldwide.

“By proceeding with plans to build the railway line, the state government could potentially deprive itself of high revenue from a natural source that the railway line itself can never generate,” said Naik.

Whole place at risk

Environmental scientist Professor T V Ramachandra of the Centre for Ecological Sciences at the IISc confirmed that populations of nothapodytes nimmoniana are present throughout the Western Ghats. “However, this tree alone is not a reason to scrap the railway proposal,” he told DH.

“Our studies have shown that developmental projects in the region have a detrimental effect on water catchment areas and in carbon sequestration, which means that Ghats will see a reduced ability to soak up carbon dioxide emissions,” Dr Ramachandra said.

(Additional inputs from Pavan Kumar H)