It was recently discovered that ouabain, long thought to be exclusively a plant product, is actually synthesized by animals, and secreted from the adrenal cortex to regulate body osmosis and cellular concentrations of sodium. The image below represents its biosynthesis and metabolism in humans.
Though there are currently synthetic schemes for the production of Ouabain, the compound is usually extracted from the plant sources Strophanthus gratus (left) and Acokanthera schimperi. Somalia is both the native habitat of these plants and the etymological origin of the name ouabain. Somalian tribes have historically used ouabain poisoned arrows for hunting. These arrows are capable of killing a hippopotamus, likely due to cardiac arrest.