A compound derived from a traditional Chinese medicine may reduce the incidence of kidney-destroying cysts in people prone to the illness, researchers report.

A Yale University team led by Dr Craig Crews tested the compound, called triptolide, in mice bred to have a disease similar to human polycystic kidney disease. Triptolide is found naturally in Lei Gong Teng, a medicinal herb used for centuries in China to fight cancer, inflammation and auto-immune disorders.

In polycystic kidney disease, genetic signals that normally inhibit cell growth are turned off, leading to the proliferation of organ-destroying cysts. Patients often lose one or both kidneys and are forced to wait for transplant or go on dialysis.

In the study, Crews' team found that triptolide prevented cyst formation in mice. "If we were able to slow the rate of cyst formation by even 10 percent a year, compounded annually, patients would not die from this disease," he said in a statement. "A relatively small effect would have an enormous clinical benefit."

The findings were scheduled to be presented in early May at the Experimental Biology 2007 meeting in Washington, D.C.