Pseudohypericin is necessary for the light-activated inhibition of prostaglandin E2 pathways by a 4 component system mimicking an Hypericum perforatum fraction

An anti-inflammatory guided fractionation of Hypericum perforatum (Hp) was used because most Hp research has traditionally focused on its anti-depressant and cytotoxic properties. The combination of 4 constituents (chlorogenic acid, amentoflavone, quercetin, pseudohypericin) explained the activity of a subfraction in light-activated but not dark conditions, and pseudohypericin was necessary but not sufficient for the anti-inflammatory activity.