Abstract

P. auritum Kunth leaves commonly known as “hierba santa” or “acuyo” or false Kava is used in Mexican Traditional Medicine as a tranquilizing and appetite stimulant agent, as well as a remedy for the relief of headache. The objective of the present work was to evaluate the effects of organic and aqueous extracts of Piper auritum Kunth (Piperaceae) leaves on the Central Nervous System (CNS) in mice. For acute toxicity evaluation, the LD₅₀ of all extracts were determined according to Locke's method.  Effects of both the organic and aqueous extracts of P. auritum leaves were tested in sodium pentobarbital-induced sleep, hot plate and open field tests. The anxiolytic-like effects were determined in burying behavior and hole-board models. In this study we demonstrated for the first time that both organic and aqueous extracts of the leaves of P. auritum possess antinociceptive effect while at higher doses the organic extracts exert a depressant effect on the CNS in mice. The aqueous extract showed antinociceptive and anxiolytic-like effects in the model tested, without affecting the locomotor activity of experimental animals.  Acute toxicity tests show that the intake of extracts of different polarities of P. auritum involves no health risks.  The present study supports, in part, the uses of P. auritum leaves as a tranquilizer, sedative agent, and as a remedy for the relief of pain in Mexican traditional medicine.

Key words: Depressant, sedative, acuyo, hierba santa, analgesic, antianxiety.