Rauwolfia serpentina (or snakeroot or sarpagandha) is a species of flowering plant in the family Apocynaceae. The plant, especially its root and bark extract, can often be found in performance enhancing supplements. The root of Rauwolfia serpentina has been employed for centuries in native Indian medicine for various central nervous disturbances including anxiety, excitement, psychosis and epilepsy . Rauwolfia alkaloids (Reserpine, Serpentine, Serpentinine, Rauwolfinine ) are used to treat high blood pressure (hypertension).
Rauwolfia Serpentina (Reserpine) for Treating High Blood Pressure
In 1940 Rauwolfia seprentina was first mentioned in the literature for its value in human cases of hypertension . Two years later, Bhatia reported that Rauwolfia seprentina is well-tolerated and useful medicine for treating high blood pressure . Wilkins and Judson  have administered Rauwolfia serpentina to over 100 patients for periods of a month to a year. They reported that it is useful in lowering high blood pressure levels. Many studies are concluding that rauwolfia extracts or its pure alkaloid reserpine are a good agent in the treatment of hypertension [1,3,4,5].
Lowering high blood pressure prevents strokes, heart attacks, and kidney problems. Reserpine removes the store of noradrenaline from artery walls  which causes the blood vessels to relax so that blood can flow more easily and also slows the heart rate . This helps reduce blood pressure, but not greatly .
Note that rauwolfia will not cure your high blood pressure but it does help control it.
The Myth About Reserpine-induced Depression
For quite some time it has been believed that reserpine ingestion causes depression. The fact that reserpine depletes brain monoamines  was an important factor in reserpine-induced depression theory. The monoamine hypothesis is the idea that depression is caused byof monoamine in the brain . Even though this theory has been shown to be incorrect there is still an absence of plausible rival theory. After evaluating numerous case reports and group studies researchers concluded that reports of depression in persons treated with reserpine are simply recording the natural occurrence of a disorder that is unrelated to reserpine . Some observations even suggest that reserpine has a calming, sedative action that can actually be considered antidepressant [18, 19]. In fact, Davies and Shepherd  were the first to report that reserpine is an effective antidepressant in a randomized placebo-controlled trial.
Rauwolfia as Sport Nutrient
Rauwolfia serpentina can be found in sports supplements probably due to its yohimbine content . Yohimbine is an antagonist to the alpha-2 adrenergic receptor (or alpha-2 blocker, alpha-2-adrenergic antagonist). Alpha blockers work by keeping the hormone norepinephrine (noradrenaline) from tightening the muscles which causes the vessels to remain relaxed and improves blood flow and lowers blood pressure . Yohimbine can both lower and increase systemic blood pressure, depending on the dose . Yohimbine is also marketed as a weight loss supplement, however, scientific research on its efficacy is limited.
Another active constituent extracted from the bark of the Pausinystalia yohimbe tree and from the Rauwolfia root is indole alkaloid rauwolscine (also known as alpha-yohimbine, isoyohimbine, corynanthidine). Rauwolscine works via the same mechanism as Yohimbine as it is a potent and selective antagonist of alpha-2 adrenergic receptors. Decreased alpha 2-adrenoceptor sensitivity may promote the breakdown of stored triglycerides in adipose tissue .
Rauwolscine and yohimbine are also partial agonists for the human 5-HT1A receptor (a subtype of a 5-HT receptor that binds the endogenous neurotransmitter serotonin [5-HT]). So they may induce anxiolytic and serotonin-like effect . So, besides being a potent stimulant it may also elevate one’s mood.
As tested in experimental animals  rauwolscine is also anaesthetic and may even possess aphrodisiac effects. Higher doses seem to carry same side effects as yohimbine.
Other Possible Uses of Rauwolfia Serpentina Extracts
Recently, a root extract of Rauwolfia serpentina was shown to be effective in lowering the blood glucose level in animal models at doses from 10 – 60 mg/kg but showed the lethal effect by inducing sedation and mortality at doses from 100 – 250 mg/kg . Improved carbohydrate and lipid homeostasis (hyperinsulinemia, hyperglycemia, hypertriglyceridemia and hypercholesterolemia) were also reported in fructose-induced type 2 diabetic mice . It is not sure whether R. serpentina improved homeostasis by either inhibiting fructose absorption in the intestine or decreasing insulin resistance.
Rauwolfia Serpentina Side Effects and Toxicity
Many people using Rauwolfia serpentina do not have serious side effects, however, drowsiness, dizziness, tiredness, nausea, vomiting, diarrhea, slow heartbeat, and stuffy nose may occur . Side effects from alpha blockers may include a headache, pounding heartbeat, nausea, weakness, weight gain and small decreases in low-density lipoprotein (LDL) cholesterol . Long-term use of some alpha blockers can increase the risk of heart failure with long-term use . The use of rauwolfia alkaloids in pregnant rats caused birth defects . There are some suggestions that rauwolfia alkaloids increase the risk of breast cancer, however, this has not been proven.
(Other common names: Rauwolfae Radix, Indian Snakeroot, Sarpgandha, Serpiria, Rauvolfia Canescens, Rauvolfia serpentina, Rauwolfia serpentine, Alpha yohimbine, Corynanthidin, Corynanthidine, Isoyohimbine, Rauwolscine hydrochloride, 17 α-hydroxy-yohimban-16α-carboxylic acid methyl ester)
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