Stigmasterol is a phytosterol with a molecular weight of 412.691 and a formula of C29H48O.
Stigmasterol is one of a group of plant sterols, or phytosterols, that includes beta-sitosterol, campesterol, ergosterol (provitamin D2), brassicasterol, delta-7-stigmasterol and delta-7-avenasterol, that are chemically similar to animal cholesterol.
The structures of beta-sitosterol and campesterol are virtually indistinguishable from that of cholesterol.
Phytosterols are insoluble in water but soluble in most organic solvents and contain one alcohol functional group.
Stigmasterol is an unsaturated plant sterol occurring in the plant fats or oils of soybean, calabar bean, and rape seed, and in a number of medicinal herbs, including the Chinese herbs Ophiopogon japonicus, or Mai men dong, and American Ginseng.
It is used as a precursor in the manufacture of synthetic progesterone, a valuable human hormone that plays an important physiological role in the regulatory and tissue rebuilding mechanisms related to estrogen effects, as well as acting as an intermediate in the biosynthesis of androgens, estrogens, and corticoids.
Studies have also indicated that a diet high in phytoesterols may inhibit the absorption of cholesterol and lower serum cholesterol levels by competing for intestinal absorption.
Studies with laboratory animals fed stigmasterol found that both cholesterol and sitosterol absorption decreased 23% and 30% respectively over a 6 week period.
Phytosterols normally are broken down into bile.