In vitro transport and uptake of protohypericin and hypericin in the Caco-2 model

The intestinal absorption characteristics of protohypericin, a protonaphthodianthrone present in Hypericum extract, were studied and compared with those of hypericin. The Caco-2 model was used as a model of the intestinal mucosa to assess transepithelial transport and cell uptake. The experimental work was performed in specific light conditions that prevented both the photoconversion of protohypericin into hypericin and the photosensitization of the cells. Following application of the individual compounds (80–200 μM) to the apical side of the monolayers, the appearance in the basolateral compartment was found to be very low (