MOLECULE

7-keto-β-Sitosterol

7-keto-β-Sitosterol or 3-Hydroxystigmast-5-en-7-one is a derivative of Beta-sitosterol that has C=O double bond positioning on C-7. It belongs to the class of organic compounds known as stigmastanes and derivatives. These are sterol-like molecules with a structure based on the stigmastane skeleton, which consists of a cholestane moiety bearing an ethyl group at the carbon atom C24 and a trans double bond in position C22. 7-keto-β-Sitosterol is one of several phytosterols (plant sterols) with chemical structures similar to that of cholesterol. Phytosterols consist of four fused rings as a core structure and an acyclic side chain. Phytosterols differ only in carbon side chains and/or presence or absence of a double bond. They play a similar role to cholesterol in stabilizing membrane lipids in plants. Phytosterols derive from the same biosynthetic precursor as the triterpenoids (2,3-oxidosqualene) and their biosynthesis also proceeds via the mevalonic acid pathway (MVA), mainly in the cytosol. In humans the intake of naturally occurring phytosterols ranges between ~200–300 mg/day depending on eating habits (PMID: 28702423). Phytosterols have cholesterol-lowering properties (reducing cholesterol absorption in intestines) and can reduce cholesterol in human subjects by up to 15% (PMID: 28702423). They may also have a role in cancer prevention and treatment (PMID: 26086253). Phytosterols naturally occur in small amount in vegetable oils, especially soybean oil. One such phytosterol complex, isolated from vegetable oil, is cholestatin, composed of campesterol, stigmasterol, and brassicasterol, and is marketed as a dietary supplement. 7-keto-β-Sitosterol or 3-Hydroxystigmast-5-en-7-one is found in plants belonging to the Brassica family and can be isolated after saponification from Brassica napus (rapeseed) and Glycine max (soyabean) oil. 7-keto-β-Sitosterol is one of several phytosterols found in cannabis plants (PMID: 6991645).