Phytosteroids, also known asplant steroids, arenaturally occurringsteroids that are found inplants.[1] Examples includedigoxin,digitoxin,diosgenin, andguggulsterone, as well asphytosterols[a] likeβ-sitosterol.[1]
Steroid pharmaceuticals that are identical or similar to humansteroid hormones are very widely used in medicine. However, the four-ring structure of a steroid is quite expensive to replicate using direct synthetic methods.
In 1938–1940, American chemistRussell Earl Marker developed the process known asMarker degradation, which convertsdiosgenin from MexicanDioscorea yams into16-dehydropregnenolone acetate, which has a four-ring structure and can be used to synthesize commonly used steroid hormones. Marker's process reduced the price ofprogesterone from $80/gram in early 1944 to $2/gram in 1951.[2]
Also in 1940, American chemistPercy Lavon Julian discovered a process to convert a much more abundant phytosteroid --stigmasterol fromsoybean -- into progesterone. Stigmasterol is a byproduct of soybean oil refinement.[3] His process was improved byPadmanabhan Sundararaman andCarl Djerassi in 1977, just as stocks of wild Mexican yam became depleted.[4] Soy stigmasterol soon replaced yam diosgenin as the main starting material for hormone production globally.[5]
