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):
Ophelia a friend whom he trusted and she lied to him. After Hamlet storms out, Ophelia makes her "O, what a noble mind is here o'erthrown" soliloquy. The next time Ophelia appears is at the "Mousetrap Play", which Hamlet has arranged to try to prove that Claudius killed King Hamlet. Hamlet sits with Ophelia and makes sexually suggestive remarks; he also says that woman's love is brief. Later that night, after the play, Hamlet kills Polonius during a private meeting between Hamlet and his mother, Queen Gertrude. At Ophelia's next appearance, after her father's death, she has gone mad, due to