Ruta graveolens the isolation of the furanocoumarin chalepensin. The essential oil of "R. graveolens" contains two main constituents, undecan-2-one (46.8%) and nonan-2-one (18.8%). The bitter taste of its leaves led to rue being associated with the (etymologically unrelated) verb "rue" "to regret". Rue is well known for its symbolic meaning of regret and it has sometimes been called "herb-of-grace" in literary works. It is one of the flowers distributed by the mad Ophelia in William Shakespeare's "Hamlet" (IV.5): It was planted by the gardener in "Richard II" to mark the spot where the Queen wept upon hearing news of Richard's capture (III.4.104–105):
Hamlet (1948 film) see the ghost, is now also convinced that Hamlet is mad. Hamlet is deported to England by Claudius, who has given orders for him to be killed once he reaches there. Fortunately, Hamlet's ship is attacked by pirates, and he is returned to Denmark. In his absence, however, Ophelia goes mad over Hamlet's rejection and the idea that her own sweetheart has killed her father, and she drowns, supposedly committing suicide. Laertes (Terence Morgan), Ophelia's brother, is driven to avenge her death, as well as his father's. Claudius and Laertes learn of Hamlet's return and prepare to have him killed.