It is a kind of natural chemical components widely distributed in nature, including plant sterols, bile acids, C21 quinones, insect metamorphic hormones, cardiac glycosides, steroidal saponins, steroidal alkaloids, scorpion venoms and the like. Despite their wide variety, their structures have a steroidal core of cyclopentane oxime polyhydrophenanthrene.
Cholesterol is the earliest discovered carcass. Gallstones are almost entirely composed of cholesterol, and cholesterol is named after it. Cholesterol is mainly found in the blood, fat, brain and nerve tissues of animals. Many animal hormones belong to sterols, such as progesterone in sex hormones, testosterone, estradiol and corticosterone in adrenal hormones.