Antinociceptive effect of the essential oil of Lippia sidoides on mice

R. M. Marçal; D. M. Ptak; R. R. Krempser; M. R. Krempser; G. C. Cardoso; R. B. Santos; A. F. Blank; P. B. Alves

doi:10.1055/s-2006-950091

Planta Medica, Inhaltsverzeichnis

Antinociceptive effect of the essential oil of Lippia sidoides on mice

RM Marçal ¹, DM Ptak ¹, RR Krempser ¹, MR Krempser ¹, GC Cardoso ², RB Santos ³, AF Blank ³, PB Alves ²

¹Physiology Department
²Chemistry Department
³Agronomy Engeneering Department, Federal University of Sergipe, Av. Marechal Rondon, s/n; CEP 49.100–000, São Cristóvão, SE, Brazil

Abstract

Lippia sidoides Cham. (Verbenaceae), an aromatic medicinal shrub, is used in Brazilian folk medicine to combat bacterial infections, inflammation and pain [1]. The aim of this study was to investigate the possible analgesic effect of Lippia sidoides essential oil on two pain models in mice, namely acetic acid-induced writhing [2] and hot-plate [3] tests. Leaves of L. sidoides were collected in São Cristóvão county (10€56'S, 37€05'W), Brazil. Essential oil was obtained by steam distillation in a Clevenger-type apparatus (4.1% yield) and analyzed by gas chromatography/mass spectroscopy. p-Cymene (26.8%), thymol (21.9%) e myrcene (12.8%) are identified as the major constituents. A dose-related antinociceptive effect was obtained in the acetic acid-induced writhing test at doses of 100, 200, and 400mg/kg (s.c.; p>0.5; p<0.05; p<0.01, respectively). In the hot-plate test, the essential oil (25–200mg/kg; s.c.) significantly increased the latency at doses of 100 (p<0.05) and 200mg/kg (p<0.01). The essential oil-induced antinociception in hot-plate test (200mg/kg; s.c.) was antagonized by naloxone (3mg/kg; i.p.). In conclusion, the essential oil of Lippia sidoides showed antinociceptive effect in chemical and thermal models of nociception in mice. The activation of opioidergic system appears to play a crucial role in the observed antinociceptive effect.

Acknowledgments: CNPq.

References: 1. Girão, V.C.C. et al. (2003), Preventive Veterinary Medicine 59: 95. 2. Koster, R. et al. (1959), Fed. Proc. 18: 412. 3. Ankier, S.I. (1974), Eur. J. Pharmacol. 27: 1.