Central Nervous System Pharmacological Effects of Plants from Northern Peruvian Andes: Valeriana adscendens, Iresine herbstii and Brugmansia arborea

Abstract

Traditional medicine is a primary source for the study of medicinal plants. In some countries, knowledge about the therapeutic use of medicinal plants is very deep and very often “magical” plants also are used to diagnose and treat illnesses. The study of these plants can help in the research of metabolites active on the central nervous system. Valeriana adscendens Trel. (Valerianaceae), Iresine herbstii Hook. (Amaranthaceae) and Brugmansia arborea (L.) Lagerheim (Solanaceae) are used in the northern Peruvian Andes for magic-therapeutic purposes. The traditional healers use V. adscendens and I. herbstii with the ritual aim to expel bad spirits from the body. Furthermore, I. herbstii was used in association with other plants, such as Trichocereus pachanoi Britt. et Rose, for divination, to diagnose diseases, and to take possession of another identity. Also, species of Brugmansia have been reported to be used during ritual practices for magical and curative purposes. Since there are no data in the literature about the chemical composition and pharmacological properties of these plants, the present paper reports the results of some pharmacological tests performed with V. adscendens, I. herbstii and B. arborea and a chemical study of these plants in order to ascertain the nature of their central nervous system activity. The tests considered to evaluate the central nervous system activity were: locomotor activity, motor coordination, pentobarbital-induced sleep, stereotyped behaviour, catalepsy, nociceptive assays and transmurally stimulated guineapig ileum. Moreover, three pure alkaloids isolated from B. arborea were evaluated for their effects on in vitro morphine withdrawal. We also evaluated the effects of V. adscendens extracts on GABA uptake and amino acids neurotransmitters content in mice synaptosomes. The results of our experiments indicate that all the above tested plants were able to reduce significantly the central nervous system activity of the animals. Furthermore, the chemical study performed for B. arborea indicated the possible constituents responsible for the central activity. The reduction of motor coordination and stereotyped behaviour together with induced locomotor activity support the possibility that all the studied plants act as psychotropic agents, thus confirming their ritual use.