US 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.

(Agencies)