Sophora Subprostrata (Shan Dou Gen)

Sophora tonkinensisSophora subprostrata, also known as Sophora tonkinensis, comes mainly from natural sources rather than cultivation since large-scale farming hasn’t developed yet so far. Its medicinal part is root, which is thus called Sophora Root or Shan Dou Gen as a Chinese herb. But don’t confuse it with Sophora Flavescens Root (Ku Shen) as both of them share this common name. The traditional medicinal uses of this herb are to treat sore throat, swollen gums, lung-heat cough, damp-heat jaundice, nasopharyngeal cancer, and so on. And Modern research has also found that it contains alkaloids and oxymatrine, which can promote coronary blood flow, inhibit tumor cell proliferation, and improve the immunity. However, it must be pointed out that after years of harvesting, the wild sources of this herb are decreasing and in some origins it is already close to exhaustion.

What is sophora subprostrata?

This plant comes from the family Legumes and its binomial name is Sophora tonkinensis Gagnep. Since sophora subprostrata root is the main medicinal part, medicinally it mainly refers to the dried roots and rhizomes. Hence, other names of this root herb include Sophora Root, Radix Sophorae Tonkinensis, Guang Dou Gen, and so on. In China it is basically produced in Guangxi, Guangdong, Jiangxi, and Guizhou. It can be collected throughout the year, in particular in autumn. And then it still requires removing impurities, washing, and drying. And it is normally used sliced and raw clinically.

Sophora subprostrata is a shrub, 1 to 2 meters in height. Pinnately compound leaf is alternate; leaflets are 11 to 17 in number, ovate or oblong-ovate, 1 to 2.5cm long, 0.5 to 1.5cm wide, and with a larger leaflet atop, sparsely pubescent upper side, and lower side covered with short dense gray-brown pubescence; small petiole is short and hairy. Axillary or acrogenous racemes are hairy; calyx is wide bell-shaped; corolla is butterfly-shaped and yellowish white; stamens are 10; ovary is densely pubescent, and with curved style and villous stigma. Pod looks like a string of beads or a chain of pearls. Bloom time is from May to June and fruiting time is from July to August. And its habitat is limestone mountain or rock crevices.

Root contains matrine, oxymatrine, N-methylcytisine, anagyrine, sophoranone, sophoranochromene, sophoradin, pterocarpine, maackiain, and so on.

Sophora subprostrata health benefits

From the point of view of traditional Chinese medicine, this herb is considered extremely bitter and cold on medicinal properties, which make it an ideal medicine for sore throat caused by the accumulation of heat toxic. And it goes to stomach meridian and is good at clearing stomach fire. As a result, sophora root, alone or in combination with other herbs, can be used to treat the swelling of the gums and tongue and mouth sores due to flaming stomach fire. What’s more, it still cures damp-heat jaundice, lung-heat cough, boils, and other conditions. And its modern pharmacology has more to tell.

Modern pharmacological actions of sophora root

1) It has anti-cancer effect since it contains matrine and oxymatrine, which show inhibition on experimental tumor;
2) It has anti-ulcer effect. That being said, it can inhibit gastric acid secretion and effectively repair experimental ulcers;
3) It has inhibitory effect on Staphylococcus aureus, Shigella, E. coli, Mycobacterium tuberculosis, vibrio cholera, leprosy bacillus, Epidermophyton floccosum, Candida albicans, and leptospira;
4) Anagyrine (C15H20ON2) and cytisine contained possess respiratory stimulant effect;
5) Oxymatrine and sophocarpine contained have strong anti-asthmatic effect;
6) It still can increase white blood cell count, treat an abnormal heart rhythm, diminish inflammation, and protect liver.

Sample sophora tonkinensis recipes on herbal remedies

The Chinese Pharmacopoeia believes that it is bitter in flavor and cold and toxic in nature. It covers meridians of lung and stomach. Elementary functions include clearing away heat and toxic materials, making a swelling go down, and relieve sore throat. Fundamental sophora subprostrata effects and indications are accumulation of fire toxin, swollen sore throat, and painful swollen gums around tooth. Recommended dosage is from 3 to 6 grams.

1) Shan Dou Gen Wan from Ren Zhai Zhi Zhi Fang Lun (Renzhai’s Comprehensive Prescriptions). It is formulated with Da Huang (rhubarb), Sheng Ma (Black Cohosh), and Pu Xiao (Glauber’s salt) to treat lump-like sensation in their throat and sore throat due to accumulated heat.

2) Shan Dou Gen Tang from Ci You Xin Shu (A New Book of Benevolent Pediatrics). It is combined with She Gan (Belamcanda Rhizome), Mai Men Dong (Mondo Grass), Tian Hua Fen (Trichosanthes Root), Gan Cao (Licorice Root), and Yuan Shen (radix scrophulariae) to cure the Taiyang and Shaoyin fire held back by wind-cold pathogen, which is mainly manifested as throat soreness, thick phlegm, and unbearable pain in throat.

3) Shan Dou Gen Fang from A New Book of Benevolent Pediatrics. It is coupled with Zi Su Ye (Perilla Leaf) to heal scrofula caused by heat-toxic in throat.

4) Qing Liang San from Zeng Bu Wan Bing Hui Chun (Supplement to Restoring Health from Tens of Thousands of Diseases). It is matched with Jie Geng (Balloon Flower Root), Zhi Zi (Gardenia), Lian Qiao (Forsythia), etc. to treat severe sore throat due to accumulated toxic heat.

Sophora subprostrata side effects and contraindications

Large doses of total alkali of sophora subprostrata root have negative chronotropic effect, negative dromotropic effect, and cardiac repolarization disorders to heart. And it excites and then inhibits the respiratory center. The toxic ingredients may be matrine, oxymatrine, and sophocarpine. The main symptoms of poisoning include varying degrees of headache, dizziness, nausea, vomiting, abdominal pain (or diarrhea), weakness of limbs, palpitations, and chest tightness; in severe cases the manifestations include pale complexion, trembling limbs, numbness, sweating, rapid heartbeat, elevated blood pressure, instability of gait, etc.; and other symptoms follow are shortness of breath, hypopnea, limbs twitching, bruising lips and face, mydriasis, and ultimately death due to respiratory failure. The main reason for causing poisoning is overdose (more than 10 grams). So, strictly controlled doses are a must clinically. TCM wise, it shouldn’t be used in case of diarrhea due to deficiency-cold in spleen and stomach.

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