What is a chemotype of an essential oil?
Various techniques can be used to distinguish, characterize and classify plants, including morphological systems. In this way we can order plants into families, genera, species, subspecies etc. etc. But what if the plants appear morphologically identical in every way, and yet yield different products of secondary metabolism (i.e. essential oils). This particular distinction between plants below subspecies level is called a chemotype, or chemical race. For example let’s take two chemotypes of Rosemary oil (there are others!). We are all probably familiar with Corsican Rosemary oil laevo-verbenone type (Rosemarinus officnalis ct. verbenone), which has an elevated level of verbenone, as distinct from “Tunisian” Rosemary oil cineol type, which has an elevated level of cineol and a low level of camphor.
