Antinociceptive effects of the essential oil of Croton nepetaefolius on mice

• Main Authors: A.P.V. Abdon, J.H. Leal-Cardoso, A.N. Coelho-de-Souza, S.M. Morais, C.F. Santos
• Format: Article
• Language: English
• Published: Associação Brasileira de Divulgação Científica 2002-10-01
• Series: Brazilian Journal of Medical and Biological Research
• Subjects: Croton nepetaefolius; Essential oil; Analgesic; Antinociception; Formalin test; Hot-plate test
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002001000015

Croton nepetaefolius Baill., is an aromatic plant native to the northeast of Brazil where it is extensively used in folk medicine as a sedative, orexigen and antispasmodic agent. In the present study the antinociceptive effects of the essential oil of C. nepetaefolius (EOCn), administered orally, were evaluated in male Swiss mice (20-25 g). In the acetic acid-induced writhing test, EOCn (100 and 300 mg/kg; N = 14 and N = 12, respectively) was effective at the highest dose. In the hot-plate test, EOCn at 30 and 300 mg/kg, but not at 3 mg/kg, significantly increased the latency at all observation times up to the 180th min (N = 12 for each dose). In the formalin test, EOCn significantly reduced paw licking in the second phase of the test at 100 mg/kg (N = 12), but decreased it in both phases at 300 mg/kg (N = 12). At 30 mg/kg, the effect of EOCn did not differ from control values in either phase of the formalin test (N = 6). Pretreatment with naloxone (5 mg/kg, ip) significantly reversed the analgesic effect of morphine (5 mg/kg, sc) on both phases, but not that of EOCn at 300 mg/kg (N = 6) on both phases of the formalin test. The data show that orally administered EOCn promotes a dose-dependent antinociceptive effect whose mechanisms remain to be elucidated.