Dioscorea: Wild yam and hormonal synthesis
by Paul Bergner
Medical Herbalism 4(4):9
In North American herbal practice, Wild Yam Dioscorea spp., is often considered a “female herb” and in recent years is commonly referred to as containing “female hormone precursors.” While dioscorea may be useful for the spasmodic cramping of menstrual irregularities (or for the spasms of a gall bladder attack) there is no evidence that it specifically affects female hormones in a clinical situation. The rumor comes from the historical use of diosgenin, a constituent of dioscorea, as a chemical precursor for the industrial synthesis of progesterone.
In the body, the steroid hormones are synthesized from cholesterol, which is first converted to pregnenolone, and then to progesterone. Various enzyme systems convert the progesterone to the male and female hormones or to cortisone. Before the 1940s, steroid hormones for medical administration were derived entirely from the glands of animals, a very expensive and inefficient source. The chemist Russell E. Marker experimented with the conversion of plant sapogenins to progesterone, and in 1943 moved to Mexico City where he isolated diosgenin from D. mexicana. Using a chemical manipulation completely unrelated to biochemical processes, he developed an efficient way to commercially produce progesterone from diosgenin. In 1952, other chemists found a way using bacterial conversion (via Rhizopus arrhizus) to synthesize cortisone from progesterone, again through a pathway unrelated to normal synthesis in the body. Thus in the 1940s and 1950s, virtually all steroid hormones for medical use were derived from diosgenin from Mexican wild yams.
Mexican wild yam was subsequently nationalized by Mexico, blocking export. Attempts to grow it in other countries have not been successful. In 1976 the Mexican government raised the price of diosgenin by 250%, prompting a shift to other cheaper means of synthesizing steroids. Today almost all steroid hormones are produced by stigmasterol, an inexpensive component of soybeans, or from cholesterol, which is available in tons quantities from wool fat. Stigmasterol is chemically converted to progesterone, by a pathway unrelated to synthesis in the body. Stigmasterol may also be converted through a microbial process to make other steroids, including estrone or testosterone. There is no evidence that the body can use either diosgenin or stigmasterol in any way to synthesize steroid hormones, or that, if it can, that it is not as likely to produce male hormones or cortisone as it is to produce female hormones.
Warmest thanks to Dr. Steven Dentali
for the research and materials used to prepare this article.