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 apparent suicide while digging her grave. Hamlet arrives with Horatio and banters with one of the gravediggers, who unearths the skull of a jester from Hamlet's childhood, Yorick. Hamlet picks up the skull, saying "alas, poor Yorick" as he contemplates mortality. Ophelia's funeral procession approaches, led by Laertes. Hamlet and Horatio initially hide, but when Hamlet realizes that Ophelia is the one being buried, he reveals himself, proclaiming his love for her. Laertes and Hamlet fight by Ophelia's graveside, but the brawl is broken up. Back at Elsinore, Hamlet explains to Horatio that he had discovered Claudius's letter with Rosencrantz