Protopine (PTP)

Protopine is a benzylisoquinoline alkaloid occurring in opium poppy, Corydalis tubers and other plants of the family papaveraceae, like Fumaria officinalis. It has been found to inhibit histamine H1 receptors and platelet aggregation, and acts as an analgesic. Protopine is an isoquinoline alkaloid contained in plants in northeast Asia. Protopine was found to reduce nitric oxide (NO), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2) production by LPS-stimulated Raw 264.7 cells, without a cytotoxic effect. Pre-treatment of Raw 264.7 cells with protopine reduced the production of pro-inflammatory cytokines. These inhibitory effects were caused by blocking phosphorylation of mitogen-activated protein kinases (MAP kinases) and also blocking activation of a nuclear factor kappa-light-chain-enhancer of activated B cells(NF-κB).