Seaweed Extract May Help Halt Cervical Cancer Virus

In vitro research shows that carrageenan -- a red algae-derived chemical often used in food products and sexual lubricants -- inhibits human papillomavirus infectivity nearly a thousand-fold greater than other HPV infection inhibitors tested, National Cancer Institute (NCI) investigators recently announced.

"Our results do not prove that carrageenan will work as a practical HPV topical microbicide," Dr. John Schiller, senior NCI investigator and a coauthor, said in a prepared statement. "The potent inhibition of infection of cells in dishes, coupled with the fact that carrageenan-based products are already in use, are promising. But we will need to do a well-controlled clinical trial before use of any of these products as an HPV inhibitor could be recommended."

However, Schiller and colleagues were "floored" by the magnitude of how better carrageenan was compared to anything else they tested.

HPV is much more sensitive to carrageenan's inhibitory effect than is HIV, against which the chemical is being studied in South African trials, said lead author Christopher Buck.

Protection against HPV-related cancer requires multiple tools, including an HPV vaccine, said Dr. Connie Trimble, an HPV researcher at Johns Hopkins. Trimble was engaged in early HPV vaccine trials and is now researching a maintenance vaccine for women with HPV.

"We wouldn't expect it to be as efficacious as the vaccine -- you have to use it all the time to prevent infection," said Dr. Doug Lowy. "But the vaccine's just too expensive for some parts of the world." "It's entirely possible that it could be tried and found not very effective," he said. "We hope that's not the case. We think the tissue culture data are strongly suggestive that it would be well worthwhile to carry out the clinical trial that addresses that question."

The full report, "Carrageenan Is a Potent Inhibitor of Papillomavirus Infection," was published in the Public Library of Science Pathogens (2006;2(7):e69).

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