Wild Yam
Scientific Name(s): Dioscorea villosa L. Dioscoreaceae (yams)
Common Name(s): Wild yam root , colic root , yuma , devil's bones , rheumatism root , China root
Clinical Overview
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 User Reviews & Ratings
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Uses of Wild Yam
Dioscorea has been promoted for the treatment of menstrual dysfunction, nausea in pregnancy, urinary tract infections, rheumatoid arthritis, cholera, nervous excitement, and gas expulsion. However, research reveals no clinical data regarding the use of wild yam for any condition.
Wild Yam Dosing
Wild yam root was used traditionally as a diaphoretic and expectorant at doses of 0.4 to 4 g/day, although there are no recent clinical studies to substantiate this dosage.
Contraindications
Contraindications have not yet been identified.
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.
Wild Yam Interactions
None well documented.
Wild Yam Adverse Reactions
In large doses, D. villosa root may cause nausea, vomiting, and diarrhea.
Toxicology
No data.
Botany
Dioscorea villosa is a twining vine native to the central southeastern US and found less frequently in the Appalachian region. It is a dioecious plant with inconspicuous white to greenish yellow female flowers and smooth heart-shaped leaves. A Chinese species, Dioscorea opposita Thunb., is also occasionally found in herbal commerce. There are more than 500 species of Dioscorea worldwide.
History
Wild yam was popularized by the Eclectic medical movement in the 19th century for its supposed antispasmodic properties and prescribed for biliary colic and spasm of the bowel. More recently, it has been promoted for the relief of nausea in pregnancy, and for amenorrhoea and dysmenorrhea. 1 Further indications have been reported for urinary tract infections, rheumatoid arthritis, cholera, nervous excitement, and gas expulsion.
Chemistry
While substantial amounts of chemical investigation have been made on other species of Dioscorea , there is little current work on D. villosa . As with many species of Dioscorea , D. villosa is a source of diosgenin. 2 , 3 , 4 It is not as prolific a producer of diosgenin as D. zingiberensis , D. floribunda , or other species. Diosgenin is not typically found in the free state in plants but commonly occurs as the saponins dioscin and gracillin. The saponins of D. villosa have not been elucidated, nor have other constituents of the species been investigated. A high performance liquid chromatography (HPLC) method for separation of dioscin, gracillin, and other Dioscorea saponins has been reported. 5
Wild Yam Uses and Pharmacology
The root of D. villosa is reported to be diaphoretic and expectorant in a dose of 4 g. 6 Much of the current herbal use of wild yam is predicated on the misconception that the diosgenin contained in the product can be converted by the human body into steroid hormones, particularly progesterone, through the intermediate dehydroepiandrosterone (DHEA). This notion appears to be based on diosgenin's use as a synthetic precursor of cortisone 7 and of the steroids found in birth control pills. There is no scientific evidence to support the notion that diosgenin or dioscin can be converted by the body into human hormones.
Work with ginseng saponins has shown that metabolism by specific microbes in the gut can substantially enhance uptake of the metabolites into the body. 8 , 9 Thus, one may postulate a similar mechanism of uptake with other, otherwise poorly absorbed plant saponins such as dioscin. Research needs to be done to understand the pharmacodynamics of saponin-containing plants in humans.
Topical formulations of Dioscorea are also poorly understood, though it is unlikely that they can serve as “progesterone replacement” vehicles. The sale of supplemental DHEA as an “anti-aging” product has carried over to Dioscorea by analogy. In fact, several products containing Dioscorea and DHEA are available.
Clinical dataIn a pilot study of women using wild yam products ( D. villosa ), it was found that progesterone synthesis appeared to be suppressed compared with controls. 10 No direct effect of wild yam extract on the estrogen or progesterone receptors was found.
Dosage
Wild yam root was used traditionally as a diaphoretic and expectorant at doses of 0.4 to 4 g/day, although there are no recent clinical studies to substantiate this dosage. 1
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.
Interactions
None well documented.
Adverse Reactions
In large doses, D. villosa root may cause nausea, vomiting, and diarrhea.
Toxicology
Research reveals little or no information regarding toxicology with the use of wild yam.
Bibliography
1. Brinker F. A comparative review of Eclectic female regulators. J Naturopathic Med . 1996;7:11-26.2. Marker R, et al. Sterols. CIV. Diosgenin from certain American plants. J Am Chem Soc 1940;62:2542.
3. Wall M, et al. Steroidal sapogenins. XII. Survey of plants for steroidal sapogenins and other constituents. J Am Pharm Assoc Sci Ed 1954;43:503.
4. Sauvaire Y, et al. Diosgenin, (25R)-spirost-5-en-3b-ol; problems of the acid hydrolysis of saponins. Lloydia 1978;41:247.
5. Xu C, et al. Comparison of silica-C18-and NH2-HPLC columns for the separation of neutral steroid saponins from Dioscorea plants. J Liq Chromatogr 1985;8:361.
6. Claus E. Textbook of Pharmacognosy , 5th ed. Philadelphia, PA: Lea & Febiger, 1956:151-52.
7. Correll D, et al. The search for plant precursors of cortisone. Econ Bot 1955;9:307.
8. Akao T, et al. Appearance of compound K, a major metabolite of ginsenoside Rb1 by intestinal bacteria, in rat plasma after oral administration-measurement of compound K by enzyme immunoassay. Biol Pharm Bull 1998;21:245.
9. Hasegawa H, et al. Main ginseng saponin metabolites formed by intestinal bacteria. Planta Med 1996;62:453.
10. Zava D, et al. Estrogen and progestin bioactivity of foods, herbs, and spices. Proc Soc Exp Biol Med 1998;217:369.
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Compare Wild Yam with other medications for the treatment of:
Rheumatoid Arthritis, Menopausal Disorders, Gallbladder Disease, Premenstrual Dysphoric Disorder
