Carvone
Carvone is a member of a family of chemicals called terpenoids. Carvone is found in large quantities in many esseential oils.
Smell
Carvones come in two optic isomeres, so called enantiomers: S(+)-carvone smells like caraway. Its mirror image, R(–)-carvone, smells like spearmint. The fact that the two enantiomeres are perceived as smelling different is proof that there must be chiral olfactory receptor molecules that respond stronger to one enantiomere than to the other. Not all enantiomers have distinguishable smell.
Occurence
s(+)-carvone is found in caraway seeds and mandarin orange peel oil. R(–)-carvone is extracted from spearmint and kuromoji oils. Some oils, like gingergrass oil, contain a mixture of both enantiomers. Many other natural oils contain lower concentration of carvones, for example peppermint oil.
Usage
The carvones are used in the food and flavor industry. Wrigley's Spearmint Gum is gum soaked in R(-)-carvone and powdered with sugar. R(-)-carvone is also used for air freshening products and -- like all essential oils -- oils containing carvones are used in alternative medicine.