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):
Prince Hamlet her son’s activities as the result of her "o’erhasty marriage" alone. Rosencrantz and Guildenstern tend to find the stalled ambitions of a courtier in their former schoolmate’s behaviour, whereas Claudius seems to be concerned with Hamlet’s motivation only so far as it reveals the degree to which his nephew is a potential threat. Ophelia, like her father, waits in vain for Hamlet to give her signs of affection, and Horatio would have little reason to think that Hamlet was concerned with anything more pressing than the commandment of the ghost. And the First Gravedigger seems to think that Prince Hamlet,