Effects of the C. nucifera extract on formalin-induced licking in mice. Animals were pretreated by oral administration different doses of the C. nucifera extract, morphine (1 mg/kg), or vehicle. The results are presented as mean ± S.D. (n = 6–10) of the time that the animals spent licking the formalin-injected paws. Statistical significance was calculated by ANOVA followed by Bonferroni’s test. * indicates p < 0.05 when comparing to the vehicle-treated group.