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
Ground substance as hyaluronic acid, heparan sulfate, dermatan sulfate, and chondroitin sulfate, proteoglycans which GAGs are bound to, and glycoproteins. Components of the ground substance are secreted by fibroblasts. Usually it is not visible on slides, because it is lost during staining in the preparation process. Link proteins such as vinculin, spectrin and actomyosin stabilize the proteoglycans and organize elastic fibers in the ECM. Changes in the density of ground substance can allow collagen fibers to form aberrant cross-links. Loose connective tissue is characterized by few fibers and cells, and a relatively large amount of ground substance. Dense connective tissue has a