More Troubles for Supplement
Aherbal supplement recently pulled from store shelves because it contained traces of a prescription blood thinner also was contaminated with two other drugs, a detailed analysis has shown.
Researchers from UC San Diego, Rational Therapeutics of Long Beach and two other institutions discovered diethylstilbestrol, or DES, in the supplement as well as the blood thinner warfarin and the anti-inflammatory drug indo- methacin. The study examined samples of PC SPES manufactured from 1996 to 2001.
DES has highly potent estrogenlike properties that could explain the apparent effectiveness of PC SPES in reducing tumor growth in men who had failed other types of prostate cancer therapy, the researchers reported.
When applied to cancer cells in a test tube, the study showed that the highest degree of biological activity was in samples of PC SPES that contained the highest concentrations of DES. Use of DES is associated with side effects such as breast enlargement, hot flashes and nausea.
The study, undertaken by doctors interested in the remedy’s apparent effectiveness, was reported last week at the annual meeting of the American Assn. for Cancer Research in San Francisco.
In February, the California Department of Health Services requested a recall of PC SPES after its testing revealed contamination with warfarin. PC SPES, which is a blend of eight Chinese herbs, is made by BotanicLab in Brea.
A spokesman for BotanicLab, John Sonego, said the company was surprised by the new study showing three contaminants in the product.
“Our testing, and testing from independent researchers, didn’t find DES,” says Sonego. “The Department of Health Services testing didn’t find anything but warfarin.”
Chemists at BotanicLab believe the warfarin detected in PC SPES could actually be a naturally occurring compound called phytocoumarin, which is found in more than 300 green plants and has characteristics similar to warfarin, Sonego said.
However, Sonego said Botanic- Lab is revamping its manufacturing process to avoid future contamination. The measures include establishing an improved quality control system, switching raw herb suppliers and moving the manufacturing facilities from Brea to China.
He said the company does not know how contamination might have occurred.
“If there was a contamination problem, we believe it was with the suppliers in China,” Sonego said. “One of the things this whole issue did for us is made us realize that when you are importing ingredients from China, you have to be really careful about quality.”
The company plans to submit new samples of PC SPES to the Department of Health Services soon in order to obtain permission to resume sales.
