He then sent his technician to the local health food store and bought three different brands of St. John’s Wort, extracted those, added the extract into the same assay, and asked whether those also could drive the expression of this gene, and they did. They were then able to chemically separate dozens of components of St. John’s Wort and ask, which of the chemical constituents of St. John’s Wort is capable of up regulating PXR activity and CYP3A expression? And of all of those, the drug that I mentioned before -- hyperforin -- which is a key component, we believe, of anti-depressant action of St. John’s Wort was exactly the moiety that activated this cascade.