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):
Gertrude (Hamlet) o'erhasty marriage." In Act three, she eagerly listens to the report of Rosencrantz and Guildenstern on their attempt to cheer him, and supports the King and Polonius' plan to watch Hamlet from a hidden vantage point as he speaks with Ophelia, with the hope that her presence will heal him. In the next act, Gertrude tells Claudius of Polonius' murder, convinced that Hamlet is truly mad. She also shows genuine compassion and affection as she watches along with others as Ophelia sings and acts in absolute madness. At Ophelia's burial, she expresses her former hope that the young woman might