Representatives of this numerous genus from the family of the same name Dioskoreinov settled mainly in tropical and subtropical countries, and mainly in Asia. There, as well as in Central America, it is grown under the name yams. As this crop in different countries are cultivated dioscorea tuberous (Dioscoreabulbifera), dioscorea opposite(Dioscoreaopposita) and Dioscorea hairy(Dioscoreavillosa), common in North America. Remember how Mommy from Gone With the Wind tries to feed Scarlett with yams before going to the Wilkes' ball?
Many types are used in traditional Chinese medicine for a variety of diseases, for example, dioscorea rhizomes are used for prolonged indigestion, coughing, infertility. And Dioscorea hairy is used in folk medicine as an antirheumatic agent, and in homeopathy for colitis.
But two particularly hardy representatives are found in our country. Growing in the Far East dioscorea nippon(Dioscoreanipponica), and in the Caucasus - Dioscorea Caucasian (Dioscoreacaucasica). Both of them are quite rare plants, and therefore are listed in the Red Book. These are dioecious herbaceous vines with horizontal rhizomes.
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Dioscorea Caucasian has ovoid-heart-shaped leaves with a pointed, elongated tip and well-visible veins, which are collected in whorls in the lower part, and are arranged alternately in the upper part of the stem. In Dioscorea Nipponskaya, the leaves are arranged alternately, the leaf blade of the lower leaves is seven-lobed, the upper ones are 3-5 lobed. The flowers of the dioscorea are inconspicuous, greenish-white, the staminate flowers are collected in half-umbels, and the pistillate ones are in the brush. The fruit is a three-celled capsule of a very unusual shape. Dried fruits can be a good addition to a dry bouquet. The capsule usually contains 3 flat seeds surrounded by a transparent wing. Plants bloom in June-July, fruits ripen by September. In the wild, the Caucasian Dioscorea is found on limestones and calcareous soils. It tolerates strong shading, prefers oak and oak-hornbeam forests. Dioscorea nipponskaya grows mainly in areas after felling and fires. It is difficult for her to compete with other herbaceous fast-growing species.
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What are these plants famous for, which received their botanical name in honor of the great physician of antiquity Dioscorides?
Tropical dioscorea species are used in folk medicine in many countries. Most of them contain steroidal saponins, a group of substances that have hormonal effects or can serve as a source of hormonal preparations of corticosteroids. The drugs Diosponin and Polisponin were obtained from Dioscorea Caucasian and Dioscorea Nipponskaya, which were used for the treatment and prevention of atherosclerosis. But alas, the area of these plants turned out to be small, the reserves of raw materials are insufficient, the plants were renewed after harvesting for a long time, the culture turned out to be laborious. These plants were gradually forgotten, the preparations were discontinued.
But this beautiful and useful plant is very easy to grow on your site. It will perfectly decorate any gazebo, pergolla, wall of the house. And it will also help fight sclerosis. In general, both beautiful and useful.
Cultivation and reproduction
I want to warn you right away that it is rather difficult to reproduce by seeds. For their germination, a high temperature of about 25-30 degrees is needed for a long time. And the seedlings are developing rather slowly. It is much easier to propagate it by pieces of rhizomes in spring or autumn. Rhizomes with buds cut into 6-7 cm pieces are planted in spring or autumn to a depth of 10-12 cm at a distance of 20-30 cm from each other.
It is better to choose a place for dioscorea warm, with neutral, not heavy in texture soils.Places where moisture stagnates for a long time in spring are not suitable. You should not choose completely shaded places and areas along the northern wall. In these conditions, dioscoreas almost do not bloom and do not bear fruit. If the soils on your site are too acidic, then be sure to produce them. In natural habitats, this plant grows on neutral or even slightly alkaline soils. In addition, all perennial rhizome and root-sucking weeds must be carefully selected on the site. In the first year after planting, while the dioscorea gets used to the new place, weeds will easily clog it. And there must be support. Without it, plants develop worse and do not look so decorative.
Care consists in weeding and loosening. In the first year after planting, in very dry weather, the plants can be watered and at the same time fed with mineral fertilizers. It is practically not affected by pests and diseases.
Chemical composition
Raw materials can be dug up for 3-4 years of life. Rhizomes are harvested in autumn or early spring before regrowth. They are dug up with a shovel, shaken off the ground, washed in cold water and cut into pieces. You can dry the roots in the sun, in the attic or in a dryer at a temperature of 60-70 degrees. Well-dried raw materials break with a crack when bent. It can be stored for up to 3 years.
The roots of most types of dioscorea contain steroidal saponins, the amount of which in dry rhizomes of dioscorea, depending on the species, age of the rhizome and growing conditions, can reach 10%. This is primarily dioscin, from which diosgenin is obtained by hydrolysis. Thanks to these compounds, the plant was used to obtain anti-sclerotic drugs (in our country), as well as to create drugs with hormonal action (abroad). By the way, they tried to create contraceptives on the basis of yam, but, unlike synthetic means, the effectiveness was insufficient.
Now about how to use this wonderful plant, or rather the two species that we can grow on our site.
Medicinal use
The decoction and powder of rhizomes has an anti-sclerotic, hypotensive, diuretic effect, reduces blood cholesterol and blood clotting. Dioscorea is prescribed for general, cerebral and coronary atherosclerosis, in the initial stages it is used for prophylaxis. As a rule, this leads to normalization of sleep and blood pressure, as well as a decrease in blood cholesterol. Treatment is carried out in cycles of 20-30 days with 7-10 day breaks for 3-6 months.
To prepare the infusion, take 1-2 g of pre-crushed rhizomes, pour a glass of boiling water and keep in a water bath in an enamel bowl for 30 minutes. Cool at room temperature, filter and take 1 tablespoon 3 times a day after meals. When taken before meals, the saponins in dioscorea can irritate the gastrointestinal tract.
But remember that dioscorea is a powerful remedy, and in case of an overdose, itching, sweating, and decreased appetite may appear. In this case, you need to reduce the dose or stop taking it, or even better, initially consult a doctor.
