6-keto-PGF1伪, the metabolite of prostacyclin, and PGE2 were measured in the supernatant of human umbilical vein endothelial cells (HUVEC) and basal or LPS-stimulated mouse coeliac macrophage cultures exposed to OBL ethanol (OBL-E) extracts and petroleum ether, chloroform, ethylacetate and butanol (PE, C, EA, B) fractions. In addition, 6-keto-PGF1伪 and thromboxane B2 (TXB2) were measured in a rat model of thromboangiitis obliterans exposed or not to OBL.
Short-term exposure to OBL-E dose-dependently increased 6-keto-PGF1伪 from HUVEC, and long-term (24 h) exposure decreased it. OBL-C and OBL-B increased 6-keto-PGF1伪, whereas the other fractions tended to decrease it after 24 h exposure. The extract and all fractions decreased basal and stimulated PGE2 production, but only OBL-EA and OBL-B reduced PGE2 in stimulated cultures to concentrations below the unstimulated values (P<0.05). In vivo OBL increased 6-keto-PGF1伪 and decreased TXB2.
OBL and its extracts increased 6-keto-PGF1伪 and reduced PGE2 and TXB2 production in a dose and time-related manner. This could indicate simultaneous inhibition of COX-2 and stimulation of endothelial COX-1. The butanol fraction seemed most promising in this respect.