What’s the first thing that comes to mind when it comes to medicinal astragalus? Chances are you will think of Astragalus root (Huang Qi). However, don’t forget that astragalus seed, also known as Chinese Milk Vetch seed and Sha Yuan Zi in Pinyin, is also a commonly used tonic thanks to its great healing properties. In TCM it has been characterized as a Chinese herb that is warm but not dry in nature. More importantly, it is also gentle and moist. Hence, milkvetch seed has a good therapeutic effect for liver and kidney deficiency caused lower back pain and weak legs, dizziness, nocturnal emission, premature ejaculation, frequent urination, enuresis, abnormal vaginal discharge, and so on. Since this is an herb with many health benefits, it is necessary to know more about it.
What is milkvetch?
Medicinally it mainly refers to Astragalus complanatus R. Br., which is a plant in the bean or pea family (Leguminosae). Its seeds are commonly used as medicine called Sha Yuan Ji Li in mandarin. In China it is primarily produced in Inner Mongolia, the northeast and northwest regions. The mature seeds are usually harvested in the late autumn and early winter when they do not crack yet, or the whole plant is pulled up by the roots. And then it needs to dry in the sun, strike them for the seeds, and remove the impurities. It is used raw or fried with salt water.
Milkvetch is a tall perennial herb, up to 1 meter in height, covered with short bristles all over the body, and with long thick taproot, and slightly flat accumbent stems. Odd-pinnately compound leaves are alternate and with a short handle; small stipules are lanceolate; petiole is short; blades are elliptic, 6 to 14mm long, 3 to 7mm wide, obtuse or emarginate apex, obtuse to rounded obtuse base, entire margin, green and hairless upper surface, and gray-green lower surface. Axillary racemes are with slender peduncle and 3 to 9 small flowers; bell-shaped calyx is green and with 5-lobed tip; butterfly-shaped corolla is yellow, and nearly rounded vexil, base with claw, shorter ala, and carina equal to vexil in length; stamens are 10; pistil is beyond stamen; ovary is superior, densely covered with white pubescence, and with gynophore; style is glabrous; stigma is with brush-like white beard. Pod is in the shape of fusiform, 3 to 4cm long, covered with short black bristles and with apex with a long beak, slightly flat back and belly, and 20 to 30 seeds inside. Kidney-shaped seeds are round. Bloom time is from August to September and fruiting time is from September to October.
Milk vetch contains fatty oil, vitamin A, alkaloids, flavonoids, phenols, tannins, proteins, amino acids, elements like selenium, copper, zinc, manganese, iron, magnesium, chromium, calcium, and so on. Seeds are rich in oil, which accounts for about 5% of the seed weight and contains at least 14 kinds of fatty acids, including heptenoic acid, myristic acid, pentadecanoic acid, hexadecanoic acid (palmitic acid), oleic acid, stearic acid, linoleic acid, linoleyl acid, arachidic acid, lignoceric acid, behenic acid, and more. And the unsaturated fatty acids account for about 40% in total acids. Besides, it still contains β-sitosterol, many amino acids, etc.
Milk vetch health benefits
Milkvetch seeds were once a tribute in Tang Dynasty due to its amazing medicinal uses. Today, it is reported that this herb is capable of reducing inflammation, inhibit cancer cell growth, decreasing lipid, lower high blood pressure, protect liver, and more. From the perspective of traditional Chinese medicine, it mainly tonifies kidney and liver, arrests seminal emission, and improves eyesight. And its modern pharmacology has said it all.
Modern pharmacological actions of astragalus seed
1) It can significantly prolong the swimming time of mice, which shows that it has anti-fatigue effect;
2) It can protect from the accumulation of the liver glycogen and reduce enzyme;
3) It has antihypertensive effect;
4) It can significantly lower serum cholesterol and triglycerides;
5) It can increase the cerebral blood flow;
6) It can improve the blood rheology indices in patients and inhibit platelet aggregation;
7) It can enhance immunity and improve the body’s specific and nonspecific immune function;
8) It can increase body weight and human tolerance to cold weather; 9) It has analgesic, sedative, antipyretic, anti-inflammatory, and anti-diuretic effects.
Sample Sha Yuan Zi recipes on herbal remedies
The Chinese Pharmacopoeia says that it is sweet in flavor and warm in nature and goes to meridians of liver and kidney. Prime functions are warming and nourishing liver and kidney, controlling nocturnal emission with astringent properties, reducing urination, and improve eyesight. Main milk vetch uses and indications include low back pain due to kidney deficiency, nocturnal emission, premature ejaculation, morbid leukorrhea, dribbling of urine, dizziness, and blurred vision. Recommended milk vetch dosage is from 9 to 15 grams.
1) Jin Suo Gu Jing Wan from Yi Fang Ji Jie (Wang Ang and his Variorum of medical recipes). It is combined with Qian Shi (Euryale Seed), Lian Xu (Lotus Stamen), Long Gu (Dragon Bones), and Mu Li (Concha Ostreae) to treat night emissions.
2) According to Ji Lin Zhong Cao Yao (Jilin Collection of Chinese Herbal Drugs), it is decocted alone to heal kidney deficiency induced low back pain.
3) According to Ben Cao Hui Yan (Treasury of Words on the Materia Medica), it is coupled with Cang Zhu (Atractylodes) to be ground into powder to cure deficient spleen-stomach, indigestion, and tympanites due to damp-heat.
4) According to Jilin Collection of Chinese Herbal Drugs, it is matched with Chong Wei Zi (Fructus Leonuri) and Qing Xiang Zi (Celosia Seeds) to treat blurred vision.
Milk vetch side effects and contraindications
Intraperitoneally administered to mice with milkvetch water-decocting and alcohol-depositing precipitant, the LD50 was 37.75 ± 1.048g/kg, as measured by Karber. In addition, intragastrically administered to wisrar rats with doses of 5.00, 2.5, 1.0g/kg, the consecutive 60-day toxicity tests, each per day, showed that hemogram, liver function, and renal function laboratory value of all doses groups were within the normal range, compared to the control group. That is to say, no significant pathological changes have been found in heart, liver, spleen, lung, and kidney. TCM wise, it shouldn’t be used in cases of flaming ministerial fire and high sex drive in males. And the Ben Jing Feng Yuan (Encountering the Sources of the ‘Classic of Materia Medica’) says that milkvetch should be avoided if kidney and bladder is with somewhat heat.