Pinyin: Shanyao
Aliases
Shuyu, Huaishanyao, Shanyu, Shanbanshu.
Source
Dioscoreaceae plant Dioscorea oppositaDioscorea oppositaDried rhizome of *Wikstroemia indica* C.A. Mey.
Botanical Description
Twining herbaceous vine. Tuber long-cylindrical, growing vertically, up to 1 m long, fresh cross-section white, highly mucilaginous, dry white and powdery. Stem usually purplish-red, dextrorse, glabrous. Leaves simple, alternate on lower stem, opposite above the middle, rarely 3-whorled; leaf blades highly variable, ovate-triangular to broadly ovate-hastate, apex acuminate, base deeply cordate, broadly cordate, or hastate to nearly truncate, margin often 3-lobed to 3-parted, middle lobe ovate-elliptic to lanceolate, lateral lobes auriculate, rounded, subquadrate to oblong, the junction between lateral and middle lobes forming various arcs; leaf variation often occurs even on the same plant. Axillary bulbils (yams) often present. Dioecious. Male inflorescence a spike, nearly erect, 2-8 in leaf axils, occasionally paniculate; rachis distinctly zigzag; bracts and perianth with purplish-brown spots; outer tepals of male flowers broadly ovate, inner ovate; stamens 6. Female inflorescence a spike, 1-3 in leaf axils. Capsule not reflexed, trigonous-oblate or trigonous-rounded, white-powdery on surface. Seeds attached to the middle of the axis of each locule, surrounded by membranous wings. Flowering June-September, fruiting July-November.
Habitat and Distribution
Grows on hillsides, valley forests, streamsides, roadsides in thickets or among weeds; or cultivated. Distributed in North, Northwest, East, and Central China.
Harvesting and Processing
Harvest after the stems and leaves wither in winter, cut off the root head, wash clean, remove the outer skin and fibrous roots, dry; or cut into thick slices while fresh, dry; alternatively, select large, straight, and uniform dried Huai Shan Yao, soak in clean water until no dry core remains, moisten thoroughly, trim both ends, roll into a cylindrical shape with a wooden board, sun-dry, and polish, commonly known as "Guang Shan Yao."
Medicinal Properties
This product is slightly cylindrical, curved and somewhat flattened, 15-30 cm long, 1.5-6 cm in diameter. The surface is yellowish-white or pale yellow, with longitudinal furrows, longitudinal wrinkles, and rootlet scars, occasionally with remnants of light brown outer bark. Heavy in weight, firm in texture, not easily broken; the fracture surface is white and starchy. Odor: faint; Taste: bland, slightly sour, sticky when chewed. Guangshanyao (processed Dioscorea) is cylindrical with flat ends, 9-18 cm long, 1.5-3 cm in diameter. The surface is smooth, white or yellowish-white.
Chemical Constituents
This product mainly contains diosgenin, dopamine, dioscorine hydrochloride, allantoin, cholesterol, campesterol, stigmasterol, hexacosanoic acid, and quinic acid, among other components.
Pharmacology
Lowers blood sugar; enhances immune function; improves digestive system function.
Properties and Channel Entry
Sweet, neutral. Enters the Spleen, Lung, and Kidney channels.
Functions and Indications
Tonifies the Spleen and nourishes the Stomach, generates body fluids and benefits the Lungs, tonifies the Kidneys and secures essence. Used for Spleen deficiency with reduced appetite, chronic diarrhea, Lung deficiency with wheezing and cough, Kidney deficiency with nocturnal emission, leukorrhea, frequent urination, consumptive Heat and wasting-thirst disorder. Dry-fried Shanyao tonifies the Spleen and strengthens the Stomach. Used for Spleen deficiency with reduced appetite, diarrhea with loose stools, excessive leukorrhea.
Dosage and Administration
Internal: decoct in water, 15-30 g, large dose 60-250 g; or prepare as pills or powder. External: appropriate amount, mash for topical application. For nourishing Yin, use raw; for strengthening the Spleen and stopping diarrhea, use dry-fried until yellow.
Precautions and Contraindications
Patients with excessive Dampness and middle-abdominal fullness, or those with Excess pathogens and accumulations, should avoid taking this herb.
Prescriptions
1. For Spleen and Stomach weakness with no desire to eat: Shanyao (Chinese Yam) and Baizhu (Atractylodes macrocephala) 30 g each, Renshen (Panax ginseng) 0.7 g. Grind the three ingredients into a fine powder, mix with boiled wheat flour paste to form pills the size of small beans. Take 30 pills with warm rice water on an empty stomach before meals. (From *Sheng Ji Zong Lu*, Shanyu Pill) 2. For Damp-Heat deficiency diarrhea: Shanyao and Cangzhu (Atractylodes lancea) in equal parts, form into pills with rice, take with rice water. (From *Bin Hu Jing Yan Fang*) 3. For phlegm-induced wheezing and rapid breathing: Mash half a bowl of Shanyao, add half a bowl of sugarcane juice, mix well, heat and drink immediately. (From *Jian Bian Dan Fang*) 4. For toxic swellings: Shanyao, Bimazi (Castor seed), and Nuomi (Glutinous rice) in equal parts, soak in water, grind into a paste, and apply to the swollen area. (From *Pu Ji Fang*) 5. For chilblains: Take a small amount of Shanyao, grind it on a new tile into a paste, and apply to the sore. (From *Ru Men Shi Qin*)
