Possible Metabolic Transformation of Pinenes to Ionones

The unintended consequence of the ingestion of certain foods to alter the scent or color of urine is well known [1]. Less awareness exists regarding the practice of ingestion of natural products or drugs with the intended purpose of conferring urine the scent of violets [2]. The resin of the terebinth tree and the derived turpentine were widely used in Antiquity in wine-making, both as taste enhancer and conserving agent, so the effect on urine was possibly noticed due to the presence in wines [3]. The scent altering effect requires metabolic conversion of pinene, the main turpentine component to ionone, the molecule mainly responsible for the scent of violets [2,4]. The metabolic pathway (in humans or otherwise) was (to our knowledge) not yet described [4]. Thus, we here propose a possible metabolic pathway for the conversion of pinene to ionone, explaining the scent altering effect of turpentine.