Eucommiae Cortex Praeparata cum Salino
Aliases：Chǎo Dù Zhòng, Yán Shuǐ Dù Zhòng, Zhì Dù Zhòng, Jiāo Dù Zhòng, Yán Zhì Dù Zhòng, Yán Zhì Dù Zhòng.
Yán Dù Zhòng is a traditional Chinese medicinal herb. It is a Chinese medicinal decoction piece processed from Eucommia bark by the salt-frying method. The product appears as small cubes or shreds, with a blackish-brown outer surface showing distinct wrinkles, and a smooth brown inner surface. The rubbery threads break easily when snapped. It has a burnt aroma and a slightly salty taste.
Efficacy & Actions
Tonifies the Liver and Kidneys; strengthens the sinews and bones; calms the fetus.
Indications
Indicated for Liver and Kidney deficiency with lower back and knee soreness and pain, weakness of the sinews and bones, dizziness and vertigo, pregnancy spotting, and fetal irritability. It may also be used for kidney deficiency with lower back pain, impotence, frequent urination, dribbling after urination, and wind-dampness arthralgia.
Modern Pharmacology
Modern pharmacological studies have found that salt-processed Eucommia possesses anti-osteoporotic, fracture-healing promoting, blood pressure-lowering, anti-fatigue, hepatoprotective, anti-aging, immunoenhancing, anti-cerebral ischemia, hypoglycemic, and lipid-lowering effects. After salt-processing, the kidney-tonifying and bone-strengthening effects of Eucommia are superior to those of the raw herb. In terms of chemical composition, LC-MS technology was used to comprehensively analyze the components of Eucommia before and after salt-frying. A total of 48 components were identified, of which 12 showed significantly increased content. Most of these are thermally decomposed aglycones, such as pinoresinol and medioresinol. Two new components—5-hydroxymethylfurfural and ferulaldehyde—were also generated. After salt-processing, total amino acid content increased by 24.232%, and total polysaccharides increased by 78.169%. The extract content of salt-processed Eucommia is higher than that of raw Eucommia, while the lead content is lower, achieving the effects of reducing toxicity and enhancing efficacy. The enhanced anti-inflammatory, anti-osteoporotic, hepatoprotective, and nephroprotective effects of salt-processed Eucommia may be related to the increased content of components such as geniposide, chlorogenic acid, aucubin, pinoresinol diglucoside, and geniposidic acid.
Ingredients
Salt-processed Eucommia primarily contains lignans, iridoids, phenylpropanoids, flavonoids, polysaccharides, and amino acids. Studies have shown that the total amino acid and total polysaccharide content significantly increases after salt-processing. Specific active components include: Lignans: Pinoresinol diglucoside, pinoresinol, medioresinol, and others Iridoids: Geniposide, geniposidic acid, aucubin, and others Phenylpropanoids: Chlorogenic acid, caffeic acid, and others Others: Total flavonoids, total polysaccharides, total amino acids, 5-hydroxymethylfurfural, ferulaldehyde, and others The Chinese Pharmacopoeia stipulates that the content of pinoresinol diglucoside (C₃₂H₄₂O₁₆) in salt-processed Eucommia shall not be less than 0.10%.
Usage & Dosage
For oral administration: decoct in water, 6–10 g. May also be made into pills or powders. Preferably used in decoctions: The aqueous decoction of Eucommia has a stronger blood pressure-lowering effect than its ethanol extract, so it is best used in decoctions. The blood pressure-lowering effect of salt-processed Eucommia is twice as strong as that of raw Eucommia, and the stir-fried form is more effective than the raw form.
Contraindications
Use with caution in cases of Yin deficiency with fire excess—as salt-processed Eucommia is warm in nature, it may generate heat and aggravate the condition. Not suitable for long-term or high-dose use as a single herb in cases of externally-contracted febrile diseases, internal excess heat, or blood deficiency with heat. Not suitable for long-term or high-dose use in patients with hypotension—Eucommia has blood pressure-lowering effects. Not suitable for long-term or high-dose use in patients with enuresis—Eucommia has diuretic effects. Not suitable for long-term or high-dose use in infants and elderly patients—Eucommia has central nervous system depressant effects. Not suitable in cases of kidney deficiency with intense fire—if it must be used, it should be combined with Phellodendron (Huáng Bǎi) and Anemarrhena (Zhī Mǔ). Contraindicated in cases of internal heat and dryness of essence and blood. Should not be used concomitantly with antihypertensive drugs such as reserpine—may cause orthostatic hypotension. Should not be used with sedative-hypnotic drugs—may increase adverse drug dependence reactions. Pregnant women and those with allergic predisposition should use under the guidance of a TCM practitioner.
Selected Formulas
For kidney-deficiency low back pain (empirical formula) Take salt-processed Duzhong (Eucommia bark) together with Buguzhi (Psoralea fruit) and walnut kernel. Decoct in water or make into pills and take. For wind-dampness impediment with pain (Bei Ji Qian Jin Yao Fang, Duhuo Jisheng Tang) Take salt-processed Duzhong with Duhuo (Angelica pubescens), Guixin (Cinnamon), and Danggui (Angelica). Decoct in water and drink. For traumatic low back pain (empirical formula) Take salt-processed Duzhong with Danshen (Salvia) and Danggui. Decoct in water and drink. For threatened miscarriage and vaginal bleeding during pregnancy (empirical formula) Take salt-processed Duzhong with Baizhu (Atractylodes) and Tusizi (Cuscuta seed). Decoct in water and drink. For soreness and weakness of lower back and knees (Salt-Processed Duzhong and Pig Tendon Soup, empirical formula) Ingredients: 20g salt-processed Duzhong (ground into fine powder), 300g pig tendon, 10g cooking wine, 5g ginger, 10g scallion, 3g salt, 3g chicken essence, 15g sugar, 10g soy sauce, 45g vegetable oil, 200ml clear broth. Preparation: Prepare and wash the pig tendon. Slice the ginger and cut the scallion into sections. Heat oil in a wok, sauté ginger and scallion until fragrant, add pig tendon, cooking wine, soy sauce, sugar, salt, chicken essence, and clear broth. Bring to a boil over high heat, then simmer over low heat. Just before serving, sprinkle in the Duzhong powder and cook briefly. Action: Tonifies the liver and kidney, strengthens sinews and bones.
Daily Consumption
Decoction for oral administration: The most common method—decoct salt-processed Eucommia in water and drink the strained liquid. Medicinal diet (medicated food): It can be stewed with ingredients such as pig tendon, black beans, and walnut kernels in soups to enhance its tonic effects. Wine infusion: Salt-processed Eucommia can be steeped in white wine to make a medicinal wine for consumption. Ointment or powder: It can be made into extracts or ground into fine powder for oral administration.
Medicinal Parts
Dried bark (processed product).
Selection & Storage
Dried bark (processed product).
