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 indicating that Hamlet has returned to Denmark, foiling Claudius' plan. Claudius switches tactics, proposing a fencing match between Laertes and Hamlet to settle their differences. Laertes will be given a poison-tipped foil, and Claudius will offer Hamlet poisoned wine as a congratulation if that fails. Gertrude interrupts to report that Ophelia has drowned, though it is unclear whether it was suicide or an accident exacerbated by her madness. Horatio has received a letter from Hamlet, explaining that the prince escaped by negotiating with pirates who attempted to attack his England-bound ship, and the friends reunite offstage. Two gravediggers discuss Ophelia's