Reserpine is an alkaloid isolated from dried roots of R. serpentine, which is used in traditional Indian medicine. Reserpine irreversibly inhibits both human isoforms of vesicular monoamine transporter, VMAT1 and VMAT2 (Kis = 34 and 12 nM, respectively). As this leads to metabolism of monoamines, reserpine is used to experimentally deplete monoamines in animals. Reserpine also inhibits the multidrug resistance protein P-glycoprotein (IC50 = 0.5 μM).
