Potentiating Effects of Lactuca sativa on Pentobarbital-Induced Sleep

Traditionally, lactuca sativa (lettuce) has been recommended for its hypnotic property. the present study was planned to investigate sleep-prolonging effect of this plant. the hydro-alcoholic extract (hae) of lettuce and its water fraction (wf), ethyl acetate fraction (eaf), and n-butanol fraction (nbf) were administrated (ip) to mice 30 min before the pentobarbital injection. moreover, both in-vivo and in-vitro toxicity of the extracts were determined. the quality of hae and nbf was also evaluated using hplc fingerprint. the hae prolonged the pentobarbital-induced sleep duration at dose of 400 mg/kg. the nbf was the only fraction which could increase the sleep duration and decrease sleep latency. the effects of nbf were comparable to those of induced by diazepam. the ld50-value for hae was found to be 4.8 g/kg. no neurotoxic effect was observed either by hae or by its fractions in cultured pc12 neuron-like cells. the results suggest that lettuce potentiates pentobarbital hypnosis without major toxic effect. the main component(s) responsible for this effect is most likely to be non-polar agent(s) which found in nbf of this plant.