Licorice ingredient ferrets out herpes.

A compound in licorice homes in on lab-grown cells infected with a herpes virus and induces them to self-destruct, a new study finds. These results suggest that a drug based on the compound could seek and destroy herpes viruses hiding in people's bodies. Current antiherpes drugs attack the virus only when it's causing symptoms.

The virus in the new study is Kaposi's sarcoma-associated herpesvirus (KSHV), which causes skin and lymph cancers. The researchers suspect that the gene responsible for KSHV's capacity to hide out is latency-associated nuclear antigen (LANA).

Researchers at New York University ran lab tests on white blood cells, some of which were infected with the herpes virus. Exposing the infected cells to the licorice ingredient, glycyrrhizic acid, shuts down LANA.

That starts a chain reaction of biochemical changes in the white blood cells, leading to their suicide and the virus' death. The uninfected cells showed no detrimental effects from glycyrrhizic acid, the researchers report in the March Journal of Clinical Investigation.

Despite these results, simply eating licorice is unlikely to purge a herpes virus from a person's system, says study coauthor Ornella Flore. Most of the glycyrrhizic acid in licorice is probably degraded in a person's stomach, she says.

To develop a treatment, Flore suggests, researchers could inject glycyrrhizic acid into animals previously infected with viruses and determine which viruses it can ferret out, how potent the drug is, and--if the results are promising--what dose would be needed in people.--N.S.