Rauwolfia root Rauvolfia serpentina

Reserpine is an alkaloid first isolated from R. serpentina and was widely used as an antihypertensive drug. It had drastic psychological side effects and has been replaced as a first-line antihypertensive drug by other compounds that lack such adverse effects, although combination drugs that include it are still available in some countries as second-line antihypertensive drugs.
 
Other plants of this genus are also used medicinally, both in conventional western medicine and in Ayurveda, Unani, and folk medicine. Alkaloids in the plants reduce blood pressure, depress activity of the central nervous system and act as hypnotics.