www.chinaview.cn 2009-07-03 14:33:41

BEIJING, July 3 (Xinhuanet) -- U.S. researchers say drugs used to treat
Parkinson's disease could also be used in a new way to combat extreme
drug-resistant tuberculosis.

The researchers by using computational strategy and subsequent experimental
validation, found the two commercially available drugs currently to treat
Parkinson's disease--entacopone and tolcapone--have the potential to treat
multi-drug resistant and extensively drug resistant tuberculosis.

"We have computational, and experimental data to support this
repositioning," Philip E. Bourne, PhD, professor of pharmacology at UCSD's
Skaggs School of Pharmacy and Pharmaceutical Sciences and the principle
investigator on the project said Thursday.

"What is exciting about this finding is that the TB target, enzyme InhA, is
already well known. But existing drugs are highly toxic and of completely
different chemical structure than entacapone or Comtan and tolcapone or Tasmar.
Here we have drugs that are known to be safe and with suitable binding
properties which can be further optimized to treat a completely different
condition."

In the study, the researchers found that the active component in both Comtan
and Tasmar -- which are used to boost the effectiveness of the Parkinson's drug
levodopa -- can also block the multiple-drug resistant tuberculosis bacterium.

The drugs block a brain chemical called COMT, in turn stopping it from
breaking down Parkinson's drugs. But their molecular structure also allows them
to block a compound that TB bugs need to build their protective cell wall.

Tasmar can damage the liver but Comtan is safer and could be used against
TB, said the resesrchers.

According to WHO, every year about 9 million new TB cases are reported in
which about 490,00 are mutliple-drug resistant TB or MDR-TB and about 40.000
extensively drug resistant or XDR-TB.