Potentiating effects of Lactuca sativa on pentobarbital-induced sleep

ABSTRACT

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 LD[50]-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