Which herb is used as antihypertensive and sedative and contains reserpine alkaloids?

• A. Rhodiola rosea
• B. Ricinus communis
• C. Rosmarinus officinalis
• D. Rauwolfia serpentina

Answer: (D)

Rauwolfia serpentina, known as Indian snakeroot, is used as an antihypertensive and a sedative because it contains reserpine alkaloids. Reserpine works by blocking the storage of monoamines (norepinephrine, serotonin, and dopamine) in nerve terminals, which lowers sympathetic nervous system activity and CNS arousal. This dual action lowers blood pressure and produces a calming effect. Historically, it was used in traditional medicine and later in conventional therapy, though it can cause depression and other adverse effects, so its use is more limited today. The other plants listed do not contain reserpine alkaloids and are not characterized by both antihypertensive and sedative effects.