Sinomenine or cocculine is an alkaloid found in the root of the climbing plant Sinomenium acutum which is native to Japan and China. The plant is traditionally used in herbal medicine in these countries for rheumatism and arthritis. However, its analgesic action against other kinds of pain is limited. Sinomenine is a morphinan derivative, related to opioids such as levorphanol and the non-opioid cough suppressant dextromethorphan. Its anti-rheumatic effects are thought to be primarily mediated via release of histamine, but other effects such as inhibition of prostaglandin, leukotriene and nitric oxide synthesis may also be involved.
Sinomenine hydrochloride is a natural anti-inflammatory morphinan analog. Sinomenine hydrochloride causes degranulation of mast cells in mammalian tissues to release histamine and suppresses production of proinflammatory cytokines. Sinomenine hydrochloride also displays antinociceptive activity, possibly through activation of the μ-opioid receptor. Stimulates short-term renewal of human embryonic stem cells (ESCs) in vitro.