Journal of Ethnopharmacology 66 (1999) 271 – 276 Acute toxicity and general pharmacological effect on central nervous system of the crude rhizome extract of Kyllinga bre6ifolia Rottb. M.C. Hellio¨ n-Ibarrola a, *, D.A. Ibarrola a , Y. Montalbetti a , D. Villalba a , O. Heinichen a , E.A. Ferro b a Pharmacology Department, Faculty of Chemical Sciences, National Uni6ersity of Asuncion, P.O. Box 1055, Asuncion, Paraguay b Phytochemistry Department, Faculty of Chemical Sciences, National Uni6ersity of Asuncion, P.O. Box 1055, Asuncion, Paraguay Received 28 July 1998; received in revised form 22 December 1998; accepted 24 December 1998 Abstract Acute toxicity and general pharmacological activities of the crude hydro-alcoholic rhizome extract of Kyllinga bre6ifolia Rottb., a popular medicine used in Paraguay, were investigated on mice. The intraperitoneal LD 50 was found to be 575 mg/kg. Oral administration of doses up to 3.0 g/kg did not provoke any toxic symptoms. Oral administration of 100 mg/kg of the extract induced a significant increase in gastrointestinal transit. In open field studies, a decrease of spontaneous locomotor activity, piloerection, passivity, palpebral ptosis, catatonia and a stereotyped behaviour was produced by the extract when administered orally (1, 10 and 100 mg/kg). A significant decrease in respiration rate was observed (1, 10 and 100 mg/kg, p.o.) using a continuous flow respiration system. Lastly, doses of 1, 10 and 100 mg/kg, p.o. of the extract produced a significant increase in the hypnotic effect induced by pentobarbital in a dose-dependent manner. The latest effects could probably explain its rational use in traditional medicine to alleviate stress or as a sedative agent. © 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Kyllinga bre6ifolia Rottb. rhizomes; Sedative activity; Central nervous system activity; Acute toxicity; Respiration 1. Introduction The rhizomes of Kyllinga bre6ifolia Rottb. (Cyperaceae) (Cyperus bre6ifolius (Rottb.) Hassk) (Kapi-i katı ´) are used in Paraguayan traditional medicine as refreshing beverage and are claimed to possess diuretic, sedative and antispasmodic properties (Gonzalez Torres, 1992; Basualdo et al., 1995). However, we have found no scientific references on any experimental evaluation either about central nervous system activity, which tra- ditional medicine ascribes to this plant, or about the toxicity of this plant. Mental ailments are apparently a member of heterogeneous diseases and, as such, will probably always require a selected arsenal of antidepressive, * Corresponding author. Fax: +595-21-585564. E-mail address: inf-fcq@sce.cnc.una.py (M.C. Hellio¨n- Ibarrola) 0378-8741/99/$ - see front matter © 1999 Elsevier Science Ireland Ltd. All rights reserved. PII:S0378-8741(99)00002-1