May 6 (HealthDay News) -- The grapefruit flavonoid naringenin inhibits the secretion of Hepatitis C virus (HCV) in infected cells and could offer a new approach for treating the disease, according to a Harvard Medical School study.

About 3 percent of the global population is infected with HCV, which can lead to cirrhosis and liver cancer. The current standard therapy of interferon and ribavirin is only effective in about 50 percent of cases and can cause major side effects, according to background information in the study.

Recent research suggests that HVC may be "hitching a ride" along the lipoprotein life cycle, and that compounds and dietary supplements that influence lipoprotein metabolism may also affect HCV.

In this new study, researchers demonstrated that HCV is actively secreted by infected cells while bound to a very low-density lipoprotein.

"Silencing apolipoprotein B (Apo-B) mRNA in infected cells causes a 70 percent reduction in the secretion of both ApoB-100 and HCV. This ApoB-dependent HCV secretion pathway suggests a novel therapeutic approach for the treatment of HCV infection," the researchers wrote.

They then tested the grapefruit flavonoid naringenin and found it reduced HCV secretion in infected cells by 80 percent.

"The concept of supplementing HCV patients' diets with naringenin is appealing," the researchers wrote. But they noted the intestinal wall doesn't absorb naringenin well, which means therapeutic doses of the flavonoid would have to be given by injection or combined with other compounds to boost its absorption by the intestines.

The researchers also noted that naringenin and several other compounds in grapefruit have significant drug-drug interactions.

"Future studies would focus on long-term ability of naringenin and perhaps other citrus flavonoids to reduce viral load in animal models and long-term cultures of primary human hepatocytes," the researchers concluded.

The study was published in the May issue of Hepatology.

SOURCE: Hepatology, news release, April 29, 2008