Indian Snake Root

Rauwolfia serpentina

Hypertension:

Rauwolfia contains the powerful alkaloid reserpine, but its effect does not include the toxicity associated with the drug of the same name. Rauwolfia has been employed for centuries for the relief of various central nervous system disorders, both psychic and motor, including anxiety states, excitement, maniacal behaviour associated with psychosis, schizophrenia, insanity insomnia and epilepsy. Powdered Rauwolfia root, as well as various forms of extracts (ethanolic, dried), has been reported to lower the blood pressure of experimental animals by various routes of administration (1). This herb exhibits dramatic strength in reducing severe hypertension. It produces sedation and a lowering of blood pressure. If administered orally, the effects of reserpine are slow, seldom appearing before 3-6 days of administration and continuing for some time after withdrawal of the herb.

Pharmacology

It is well accepted that the pharmacological effects of Rauwolfia are due to its alkaloids, especially the reserpine-rescinnamine group. Reserpine is the most important alkaloid present in root, stem and leaves of the plant. It varies from 1.7 to 3.0%. The root barks has more than 90% of the total alkaloids in roots. Ajmalicine, ajmaline, isoajmaline, ajmalinine, chandrine, rauwolfinine, renoxidine, rescin-namine, reserpiline, reserpin, reserpinine, sarpagine, serpentine, serpentinine, tetraphyllicine, yohimbine, 3-epi-a-yohimbine are the minor alkaloids identified from samples collected from India. The pharmacological activity of Rauwolfia is due to the presence of several alkaloids.

The experimental pharmacology of reserpine and related compounds has been well documented (2). Rauwolfia and its major alkaloids probably lower high blood pressure by depleting tissue stores of catecholamines (epinephrine and norepinephrine) from peripheral sites. By contrast, their sedative and tranquillizing properties are thought to be related to depletion of catecholamines and serotonin (5-hydroxytryptamine) from the brain. Following absorption from the gastrointestinal tract the active alkaloids concentrate in tissues with high lipid content.They pass the blood-brain barrier and the placenta. Rauwolfia products are characterized by slow onset of action and sustained effect. Both the cardiovascular and central nervous system effects may persist following withdrawal of the drug. The active alkaloids are metabolized in the liver to inactive compounds that are excreted primarily in the urine.

Contraindications

Rauwolfia products are contraindicated in patients with a history of mental depression (especially those with suicidal tendencies) during or shortly after therapy with monoamine oxidase inhibitors; active peptic ulcer, sinus node disorders, ulcerative colitis; epilepsy; or decreased renal function. Rauwolfia should be discontinued at first signs of depression such as despondency, early morning insomnia, loss of appetite, impotence, or self-deprecation.

References - Rauwolfia