The taxonomic group of Dioscorea belonging to the Dioscoreaceae family comprises of over 850 varieties of creeping plants that are annual, twining and bearing tubers. Together these species having edible roots are called ‘yams' and are generally found in abundance in humid (tropical) as well as warmer pleasant (temperate) climatic conditions. Among these 850 species, some that are fleshy and are rich in carbohydrates, are consumed as food in many places. On the other hand, the other varieties are gathered as they contain useful glycosides, specially botogenin and diosgenin. In laboratories, the steroidal basis of botogenin and diosgenin in glycosides are transformed to yield various steroid hormones.
It may be mentioned here that the most plentiful source of steroidal raw material is D. floribunda M. Martens and Galeotti (originally found in Mexico). Amongst these, the ostensible ‘wild yam' or D. villosa L. is traditionally best recognized as a ‘colic root'. It is a vine with a natural and hay-like, maybe even a little therapeutic, and usually found in the open forests and humid grooves mainly in the US. The ‘wild yam' naturally grows in the region from Connecticut and New York, south of Florida, west of Texas and Minnesota. Incidentally, another herb, D. quaternata, too has a parallel variety and is segregated on the basis of its technical features. It is unlikely that the collectors gathering the roots are able to differentiate between the two varieties.
Incidentally, the Japanese researchers first segregated diosgenin from Dioscorea way back in 1936. However, converting this steroidal sapogenin (non-sugar portion of saponin that is typically obtained by hydrolysis) into progesterone was done for the first time in 1940. Following this, diosgenin and botogenin formed the basis for manufacture of commercial medicines. These medications comprise contraceptives, modern hormones, general corticosteroids, androgens, estrogens, progestogens as well as other sex hormones. It may be noted here that the Dioscorea has been silently and in a roundabout way had a larger effect on social as well as medical applications than any other plant in the group during the 20th century.
In contemporary times, various products of ‘wild yam' as well as ‘Mexican wild yam' have come into view in the market and these include both the oral as well as the relevant dosage types. Incidentally, one firm operating at multi-levels had endorsed the wild yam as a ‘normal antecedent' to the DHEA hormone. Although there is no scientific substantiation to this kind of wishful thinking, the company has asserted that the body converts diosgenin into DHEA hormone. On the other hand, there are many advertisers who claim that treatment of wild yam cream on the skin consequentially changes diosgenin into progesterone in the body. There are yet other merchandises that include ‘original' progesterone with a view to ‘yield the desired results'. Interestingly, all these endorsements aim at luring clients or ‘patients' to purchase the product as the best anti-aging items in the markets. Some of them also promise the clients of healing their menstrual problems as well as osteoporosis. These are only a few claimed uses of the wild yam! A particular wild yam catalog claims that the Chinese first noted the use of the ‘wild yam' or Dioscorea villosa in 25 B.C.
It is true that diosgenin can be changed to various steroidal amalgams in the laboratory; it is also a fact that there is no chemical amalgamation of the substance inside the body. Following the wild yam scandal during the 1990s, a lot of effort and honesty are required to set up self-parameters for the herb industry to control the misuse of wild yam properties. Even the federal regulators need to work in this regard.
Till 1970 diosgenin was the only source for steroidal hormone for use in contraceptives as well as other hormones. In fact, the wild yam has had a noteworthy impact as far as balancing female hormones are concerned. Over the decades, wild yam has been conventionally useful in relieving menstrual cramps and pains in the intestine, flatulence (averting or relieving stomach and intestinal gas formation), and also pain in the ovary and uterus. In fact, steroidal saponins contained in wild yam also have anti-inflammatory or swelling properties and are useful in healing rheumatoid arthritis as well as swelling conditions in the bowel system. Wild yam is also diuretic and helpful in increasing the urine flow. When it is blended with anti-spasmodic actions, wild yam also comforts pains in the urinary tract.
Diosgenin found in wild yam brings relief to irritations and nervous conditions in all parts of the body, but is found to be less effective when the substance lacks in tenor. Wild yam is especially beneficial during pregnancy and childbirth and the above statement is valid in both the cases. The herb is an effective remedy to cure any kind of cramps arising out of tension or stress during the pregnancy period. Herbal medicine practitioners have conventionally used wild yam to cure conditions of endangered miscarriage. Many herbalists have also used wild yam in treating the nausea or vomiting tendencies during pregnancy and child birth.
Root and rhizome.
Going back to history, one comes to learn that the people of both Maya and Aztec civilizations widely used wild yam as a medicine most probably to alleviate pain. In North America, the wild yam is also known as colic root and rheumatism root which provides ample indication of how the early European settlers in this continent used the herb. Generally, the wild yam was used to get relieve from disorders marked by inflammation or pain in the connective tissue structures of the body. At the same time, herbalists in North and Central America extensively used wild yam as a traditional medicine to alleviate excruciating menstruation, ovarian pain and also during agonizing labor conditions.
Wild yam's double action of being anti-spasmodic (eases muscular spasms or cramps) as well as anti-inflammatory (qualities that can soothe irritation of the skin) makes it an efficient remedy to heal arthritis and rheumatism. At the same time, wild yam is able to diminish irritation, swelling and pain and also calms down the rigid muscles in the affected part of the body. In addition, wild yam is effective in alleviating cramps, spasms, muscle tension and colic. Significantly, the wild yam is also useful in healing most digestive disorders, including the swelling and irritation of the gall bladder, irritable bowel syndrome and diverticulitis.
Other medical uses
Habitat and cultivation
Although the wild yam is indigenous to North and Central America, over the years it has acclimatized in various other climes around the world. Presently, the herb is commercially cultivated in the tropical, semi-tropical as well as temperate climates. The herb is grown from its seeds that are sown in spring. Additionally, wild yam is also reproduced by grafting the tubers as well as root division either during spring or autumn. Bright sunlight and fertile soils are best for the plant to thrive and flourish. Usually the harvesting of the roots and tubers of the wild yam is done during autumn.
It was the Japanese scientists who first successfully isolated diosgenin from dioscin in wild yam way back in 1936. This is considered to be a major feat in medicinal science as the breakthrough led to the artificial production of several hormones. While the isolation of diosgenin from dioscin heralded the synthesis of progesterone (an important female sex hormone), it was also path breaking in the production of corticosteroid hormones like cortisone. The Japanese scientists discovered that the wild yam contained large quantities of dioscin which has anti-inflammatory properties eventually and this made the herb a popular remedy to cure rheumatic disorders.
Wild yam products can be taken in as tinctures, tablets as well as capsules prepared from the dehydrated roots of the herb. Usually, for effective use many people consume two to three ml of wild yam tincture three to four times every day. On the other hand, 1 - 2 capsules or tablets of dried wild yam roots taken thrice daily will yield similar results.
Side effects and cautions
Taking large amounts of wild yam can cause nausea.