Colchicine may increase sensitivity or enhance the response to yam plant. Comments Oral estrogen supplementation may retard the metabolism of yam plant's steroidal hormones. Most species of yams contain large amounts of plant steroids, primarily diosgenin, a saponin precursor in the synthesis of progesterone. Without the yams, the industrial complex would not be able to meet the world wide demand for synthetic corticosteroids. But with them, scientists can derive animal or human steroids in a fairly straight forward multi-step process.
Wild yams are really the only good source of plant steroids for such purposes.
Agave and Yucca are two other sources, neither of which equals wild yam. Stigmasterol, from soybeans and other herbs, comes about as close as any other plant sterol to being useful in steroid synthesis, but yields what is better called a semi-synthesis. In steroid synthesis, the carbohydrate moiety is usually split off from the 3-OH group during the isolation. This is mentioned simply to demonstrate there is not an equivalency between diosgenin and human steroids. If yam has steroidal effects on the body it is not because it contains steroidal hormones, but because the steroidal precursors have similar effects by an as yet unknown mechanism.