Catechol one of the main natural phenols in argan oil and is a component of castoreum, a substance from the castor gland of beavers, used in perfumery. It is also found in "Agaricus bisporus". Catechol moieties are also found widely within the natural world. Arthropod cuticle consists of chitin linked by a catechol moiety to protein. The cuticle may be strengthened by cross-linking (tanning and sclerotization), in particular, in insects, and of course by biomineralization. Catechols such as DHSA are produced through the metabolism of cholesterol by bacteria such as "Mycobacterium tuberculosis". Urushiols are naturally existing organic compounds that have the
Perfume used as middle notes. Manufacturers who publish perfume notes typically do so with the fragrance components presented as a "fragrance pyramid", using imaginative and abstract terms for the components listed. Grouping perfumes can never be a completely objective or final process. Many fragrances contain aspects of different families. Even a perfume designated as "single flower", however subtle, will have undertones of other aromatics. "True" unitary scents can rarely be found in perfumes as it requires the perfume to exist only as a singular aromatic material. Classification by olfactive family is a starting point for a description of a perfume, but