St. John’s Wort Protein Suppresses HIV

In a surprising finding, scientists are reporting that HIV appears to crumple when it encounters a protein found in St. John’s wort, the plant that produces a popular herbal supplement.

But if you’re an AIDS patient, don’t go rushing to the health food store just yet. The research is preliminary and far from the human-testing stage. And over-the-counter St. John’s wort supplements don’t appear to contain enough of the protein to effectively combat the AIDS virus.

Still, the scientists behind the research think they may be onto something. While the biology underpinning their experiments is complex, the findings are simple: The protein “suppresses HIV replication,” at least in brain cells tested in a laboratory, said study author Kamel Khalili, acting chairman of Temple University’s Department of Neuroscience.

“It’s another hope for people who have HIV infection and AIDS,” he said.

The results of the study, which was partially funded through grants from the National Institutes of Health, appear in the Oct. 27 issue of Gene Therapy.

St. John’s wort has one of the highest profiles of any herbal supplement, although there’s controversy about whether it actually improves health. The herbal treatment is extracted from the St. John’s wort plant, and supposedly provides relief for depression and anxiety, although critics dispute its alleged powers.

The potential connection between the plant and HIV is the product of serendipity. Khalili and his colleagues were studying whether St. John’s wort has any effect on diseased brain cells when a team member suggested testing it on HIV. The researchers liked the idea. So they cloned a newly discovered protein, called p27SJ, and used it to treat laboratory samples of HIV-infected brain cells.

The St. John’s wort protein appeared to stop HIV-infected cells from reproducing by interfering with their genetic machinery, Khalili said.

Drug treatments commonly shrink levels of HIV in the blood to zero, but the infection can remain active in the brain. Research released earlier this month suggests that the disease eats away at the brains of HIV patients even when they’re on AIDS drugs.

The new findings are promising, said Paul M. Thompson, a neuroscience researcher at the University of California, Los Angeles and co-author of the brain-thinning study. But there’s still a big question: Will doctors be able to get the protein into the brains of HIV patients?

Humans come with a built-in barrier that keeps germs from slipping from the bloodstream into the brain. But it also can keep out helpful drugs.

If the St. John’s wort protein can’t manage to slip through the blood-brain barrier, “then the focus becomes, how do you smuggle it in?” Thompson asked. “That’s a much more difficult question.”

There’s also the matter of finding sufficient supplies of the protein. The researchers tested St. John’s wort supplements found on store shelves, but it appeared to have little, if any, effect on the HIV germs, Khalili said.

“I don’t think the regular pills will do anything,” Khalili said. But the hope is that researchers will find a way to make new pills that would work, he added.

By Randy Dotinga
HealthDay Reporter