ChEBI: Sitosterol is a member of the class of phytosterols that is stigmast-5-ene substituted by a beta-hydroxy group at position 3. It has a role as a sterol methyltransferase inhibitor, an anticholesteremic drug, an antioxidant, a plant metabolite and a mouse metabolite. It is a 3beta-sterol, a stigmastane sterol, a 3beta-hydroxy-Delta(5)-steroid and a member of phytosterols. It derives from a hydride of a stigmastane. A member of the class of phytosterols that is stigmast-5-ene substituted by a beta-hydroxy group at position 3.