Corydalis (Corydalis yanhusuo)

Identification: A perennial plant that is valued medicinally for its fleshy underground root. The flowers are hermaphrodite (have both male and female organs. Researchers are interested in Corydalis because it contains as many as 20 active compounds that may prove useful in human medicine.

Habitat: Corydalis grows throughout the world, but the species Corydalis yanhusuo is native to northern China in the province of Zhejiang. The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires moist soil.

Family: Papaveraceae (Poppy family)

Other Names: Yan-Hu-Suo

Parts Used: Tuberous rhizome. The root is harvested in late spring or early summer, once the top growth has died down, and is dried for later use.

History: Corydalis is one of the chief painkillers in traditional Chinese medicine, where it’s favored for relief of arthritis, menstrual cramps, traumatic injuries, and almost all other types of pain. The herb has a mildly sedative and tranquilizing effect, and is sometimes used for mood disorders and emotional disturbances. In the folk medicine of the past, its tendency to reduce spasms won it a place in the treatment of Parkinson’s disease.

Constituents: Scientists have isolated a number of alkaloids from the tuber of corydalis, including corydaline, tetrahydropalmatine (THP), dl-Tetrahydropalmatine (dl-THP), protopine, tetrahydrocoptisine, tetrahydrocolumbamine, and corybulbine.

Medicinal Properties:
Properties: Analgesic; Antiseptic; Antispasmodic; Antitussive; Cancer; Cardiotonic; Hypotensive; Sedative.

Main Uses: Of the full range of 20 alkaloids found in the plant, THP is considered to be the most potent. In laboratory research, it has been shown to exhibit a wide number of pharmacological actions on the central nervous system, including analgesic and sedative effects. dl-THP has been found to exhibit a tranquilizing action in mice. Scientists have suggested that dl-THP blocks certain receptor sites (e.g., dopamine) in the brain to cause sedation.

In addition to its central nervous system effects, studies in the laboratory have shown the alkaloids from corydalis also have cardiovascular actions. For example, dl-THP has been shown to both decrease the stickiness of platelets and protect against stroke, as well as lower blood pressure and heart rate in animal studies. Additionally, it seems to exert an anti-arrhythmic action on the heart. This was found in a small double-blind clinical trial with patients suffering from a specific type of heart arrhythmia (e.g., supra-ventricular premature beat or SVPB). People taking 300-600 mg of dl-THP per day in tablet form, had a significantly greater improvement than those taking placebo pills.

Other human clinical trials on dl-THP have shown the ability to fall asleep was improved in people suffering from insomnia after taking 100-200 mg of dl-THP at bedtime. No drug hangover symptoms such as morning grogginess, dizziness or vertigo were reported by people taking the alkaloid extract.

Reports from Chinese researchers also note that 75 mg of THP daily was effective in reducing nerve pain in 78% of the patients tested. Painful menstruation (dysmenorrhea), abdominal pain after childbirth, and headache have also been reported to be successfully treated with THP.

Extracts of the herb may also be useful in the treatment of stomach ulcers. In a large sample of patients with stomach and intestinal ulcers or chronic inflammation of the stomach lining, a 90-120 mg extract of the herb per day (equal to 5-10 grams of the crude herb) was found to improve healing and symptoms in 76% of the patients.

Dosages: For an analgesic or sedative effect, the crude, dried rhizome is usually recommended at 5-10 grams per day. Alternatively, one can take 10-20 ml per day of a 1:2 extract.

Corydalis is available from suppliers of Asian herbal products in capsules and tablets, and as a liquid extract. Check the ingredients carefully, as Corydalis is frequently combined with other herbs.

Caution:
Do not take more than the recommended amount of Corydalis, as there is a risk of toxicity from large doses. Do not take Corydalis if you are pregnant or breastfeeding.

Possible Drug Interactions:
No drug interactions have been reported. However, it makes sense to use caution when taking it with other medications that act on the central nervous system.

Overdosage:
Corydalis contains compounds that can be toxic in large doses. Do not take more than the recommended amount.

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