– It is herbaceous twining vine in the family Dioscoreaceae. Tubers are oblong, straight, up to 1 meter, and with mucilaginous, white section when fresh. Stems are usually with purple, dextral, and hairless.
– Simple leaf is alternate in the lower part of the stem, opposite above the middle, and rarely in 3 whorls; blade is large, from ovate triangular to broadly ovate halberd, 3 to 9cm long, 2 to 7cm wide, and with acuminate apex and deeply cordate or halberd-shaped base.
– In China it is basically produced in Henan, Hunan, and regions south of the Yangtze River.
– Traditionally the one from Henan (Huaiqing) is believed with highest medicinal properties and nutritional value. That’s the reason why it is often called “Huai Shan Yao.”
Dioscorea opposita. Thunb (chin. : 山药)
– It mainly refers to the roots of Dioscorea opposita Thunb. Besides, the root of Dioscorea japonica Thunb., a species of wildlife around China, is also used as Shan Yao medicinally because of the similar efficacy.
– Hence, other names of it include Rhizoma Dioscoreae, nagaimo, Common Yam Rhizome, Dioscorea oppoistifolia, Korean yam, Dioscorea batata, Chinese yam rhizome, Chinese mountain yam, dioscorea yam, Dioscorea villosa, dioscoreae rhizoma, and so on.
– The Chinese Materia Medica says that it is sweet in flavor and neutral in nature and goes to meridians of lung, spleen, and kidney. Vital functions are tonifying spleen, nourishing lung, reinforcing the kidney, and benefitting essence.
– In Chinese herbology, these tubers are used in homeopathy as remedy. In cooking, they are used to make a variety of dishes.
– known as an anti-inflammatory, a pain reliever and an antispasmodic (relieves muscle spasms).
– An alternative healing site on traditional Chinese medicine also indicated anti-aging application.
– Historically, wild yams have been used to treat menopause symptoms, menstrual cramps, gallstones and muscle spasms.
– Strengthening the spleen and stomach to aid digestion. Fresh yam contains amylase, polyphenol oxidase, and other matters, which make it a perfect medicine and food to help digestion and absorption.
– It helps regardless of it is spleen-yang or stomach-yin deficiency. Therefore, clinically it treats deficient spleen-stomach, loss of appetite, body fatigue, diarrhea and other diseases;
– Nourishing kidney and enriching essence. It contains a variety of nutrients, which can make body stronger, nourish kidney, increase sperm count, and improve sperm quality. So, it is widely used for impotence, nocturnal emission, abnormal vaginal discharge, frequent urination, and more;
– Benefiting lung to stop cough. It contains saponins and mucilage, which have a lubricating and moisturizing effect. Hence, it benefits lung qi, enriches lung yin, and treat chronic cough due to lung deficiency and phlegm;
– Lowering blood sugar. Fresh yam contains mucus protein that can lower blood sugar. Therefore, it can be used in the treatment of diabetes or a good diabetic diet;
– Promoting longevity. Raw yam contains a lot of mucus protein , vitamins and trace elements, which can effectively stop the precipitation of lipids in the blood vessel wall and thereby prevent cardiovascular. (ie. it tranquilizes the mind, promotes intelligence, and prolongs life)
– Preventing hepatic coma. Recent studies have found that it is with sedative effect and can be used to prevent hepatic coma;
– Soothing mood and regulating sleep. Unlike ginseng, the medicinal properties of Chinese yams are quite mild and slow. And it can soothe mood and adjust sleep while regulating the function of spleen.
– Tonifying deficiency. Zhang Zhongjing, one of the best Chinese physicians in TCM history, was very good at using this herb. In his medical book Jin Gui Yao Lue (Essential Prescriptions of the Golden Coffer), it is used to cure qi-blood deficiency, stomach pain, arthralgia, amenorrhea, irregular menstruation and other symptoms.