Ajmalicine is an terpenoid indole alkaloid that has been found in R. serpentina.1,2 It is an α1-adrenergic receptor antagonist, reducing the phenylephrine-induced pressor response in pithed rats when administered at doses ranging from 1 to 4 mg/kg.3 It also binds to α2A-, α2B-, α2C-, and α2D-adrenergic receptors (Kis = 8.2, 14.5, 5, and 289 nM, respectively).4 Ajmalicine, in combination with almitrine, improves hemodynamic and metabolic parameters following transient cerebral ischemia in dogs.5
1.Sharma, V., Chaudhary, S., Srivastava, S., et al.Characterization of variation and quantitative trait loci related to terpenoid indole alkaloid yield in a recombinant inbred line mapping population of Catharanthus roseusJ. Genet.91(1)49-69(2012) 2.Srivastava, A., Tripathi, A.K., Pandey, R., et al.Quantitative determination of reserpine, ajmaline, and ajmalicine in Rauvolfia serpentina by reversed-phase high-performance liquid chromatographyJ. Chromatogr. Sci.44(9)557-560(2006) 3.Demichel, P., Gomond, P., and Roquebert, J.α-Adrenoceptor blocking properties of raubasine in pithed ratsBr. J. Pharmacol.77(3)449-454(1982) 4.Ruffolo, R.R., Jr., Bondinell, W., and Hieble, J.P.α- and β-adrenoceptors: From the gene to the clinic. 2. Structure-activity relationships and therapeutic applicationsJ. Med. Chem.38(19)3681-3716(1995) 5.Cahn, R., and Cahn, J.Curative effect of an almitrine-raubasine combination in the postischemic syndrome following transient cerebral ischemia in dogsPharmacology36(3)156-165(1988)