Akuammine is an indole alkaloid that has been found in Picralima nitida and has analgesic activity. It selectively binds to the μ- and κ-opioid receptors over the δ-opioid receptor (Kis=0.3, 1.68, and 10.4 μM for the human receptors, respectively) . Akuammine inhibits forskolin-induced cAMP production in HEK293 cells expressing human μ- or κ-opioid receptors (IC50s=2.6 and 0.073 μM, respectively) . It increases the latency to withdrawal in the tail-flick or hot plate test in mice when administered at a dose of 60 mg/kg.