London, Oct 19 (IANS):  Drugs made out of rare metals could be effective against colon and ovarian cancers, including drug resistant cancerous cells, says a new study.

The study, conducted by the universities of Warwick and Leeds, showed that a range of compounds containing the two transition metals Ruthenium and Osmium cause significant cell death in ovarian and colon cancer cells.

The compounds were also effective against ovarian cancer cells which are resistant to the drug Cisplatin, the most successful transition metal drug, which contains platinum.

"Ruthenium and Osmium compounds are showing very high levels of activity against ovarian cancer, which is a significant step forward in the field of medicinal chemistry," says Patrick McGowan, Leeds chemist and study co-author.

Sabine H. Van Rijt, lead researcher in the lab of Peter Sadler, chemistry professor in at the University of Warwick, said: "Most interestingly, cancerous cells that have shown resistance to the most successful transition metal drug, Cisplatin, show a high death rate with these new compounds."

Sadler said he is "excited by the novel design features in these compounds which might enable activity to be switched on and off".

Cisplatin was discovered in the seventies and is among the most effective cancer drugs on the market, with a 95 percent cure rate against testicular cancer, said a Warwick press release.

Its success has spurred chemists worldwide to try to discover whether other transition metal compounds can be used to treat cancer.

These findings were published in the Journal of Medicinal Chemistry.