2"These tubers have been used in some cultures as a coffee substitute. It helps support the spleen, lungs and kidneys. Dioscoreae contains up to thirteen percent diosgenin. Diosgenin has been processed and given to patients to relieve arthritis, asthma, eczema, regulate metabolism and control fertility. Diosgenin provides the steroid building blocks for developing human sex hormones and can be used for developing muscle mass and strength. It has been used for emotional instability, chronic cough, diarrhea, and diabetes." 4 "Medicinal Action and Uses: Antispasmodic. Perhaps the best relief and promptest cure for bilious colic, especially helpful in the nausea of pregnant women. Valuable also in painful cholera morbus with cramps, neuralgic affections, spasmodic hiccough and spasmodic asthma." 9 "Botanical name: Dioscorea oppositae Pharmaceutical name: Radix Dioscoreae Oppositae. English: Chinese Yam Root. Properties: sweet, neutral. Channels entered: Spleen, Lung, Kidney. Functions and clinical use: Tonifies and benefits the Spleen and Stomach: used in cases of Deficient Spleen or Stomach with such symptoms as diarrhea, fatigue, spontaneous sweating, and lack of appetite. Benefits the Lungs and nourishes the Kidneys: used for Wasting and Thirsting syndrome. Because this herb moistens and is neither hot nor cold, it benefits both the Yin and the Yang of the Lungs and Kidneys. It is also used for spermatorrhea, frequent urination, and leukorrhea." 14 "Wild yam root has been used for hundreds of years to treat rheumatism and arthritis-like ailments. The discovery of steroidal glycosides (diosgenin) in the root validated this ancient practice. 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 worldwide demand for synthetic corticosteroids. But with them, scientists can derive animal or human steroids in a fairly straightforward multi step process. Wild yams are the only really good source of plant steroids for such purposes.
Diosgenin provides about 50 percent of the raw material for steroid synthesis. It must be emphasized that there is not an equivalency between diosgenin and human steroids. It takes many synthetic steps to get from one to the other. If yam has steroidal effects on the body, it is not because it contains steroidal hormones, but because the steroidal precursors have similar effects. The body does not recognize them or mistake them for its own hormones, but uses them in a similar manner.
Research has shown that yam, yam extract and/or diosgenin possess good to excellent anti-inflammatory action. In one series of studies, yam was found to induce a short-lived decrease in blood pressure and an increase in coronary flow when injected intravenously into rabbits. Also in rabbits, the saponins of yam, fed orally, prevented large increases in blood cholesterol levels. The good therapeutic effect of dioscorea saponins on patients with atherosclerosis combined with hypertension was confirmed in Clinical practice.
The British Herbal Pharmacopoeia recognizes wild yam root as a spasmolytic, mild diaphoretic, anti-inflammatory, antirheumatic and cholagogue, for use in the treatment of intestinal colic, diverticulitis, rheumatoid arthritis, muscular rheumatism, cramps, intermittent claudication, cholecystitis, dysmenorrhea, and ovarian and uterine pain. Bilious colic and rheumatoid arthritis are specific indications for the use of yam."