ABSTRACT
Triterpenoid compounds are derived from a C30 precursor, squalene, which was first isolated from shark liver. The triterpenoids are a large and diverse group made up of several subclasses: Sterols such as stigmasterol and sitosterol are essential components of cell membranes, and they are also used as the starting material in the production of steroidal drugs. Some including diosgenin and hecogenin are used as precursors of sex hormones, cortisone and vitamin D. Steroidal saponins are thought to be responsible-at least in part-for the oestrogenic activity linked to herbs such as Dioscorea villosa and Chamaelirium luteum, though they are classed among the phytoestrogens. A subgroup of the steroidal saponins are the glycoalkaloids, in which the aglycone is a steroidal alkaloid. Cardiac glycosides increase the force and speed of systolic contraction. In the failing heart they cause a more complete emptying of ventricles and shortening in length of systole.
