Separation and purification of saponins from Semen Ziziphus jujuba and their sedative and hypnotic effects.

Semen Ziziphus jujuba (SZJ) has long been used in Chinese traditional medicine for the treatment of anxiety and insomnia because of its effect of decreasing monoaminergic system activity; saponins are thought to be the main bioactive factors. To investigate the sedative and hypnotic effects of saponins from SZJ, silica gel column chromatography and thin-layer chromatography were used to purify the crude extract of total saponins from SZJ. High-performance liquid chromatography showed that saponins from SZJ comprised two components, compounds I and II. Animal tests were conducted using these two compounds to compare their sedative and hypnotic effects. Results showed that both compounds had a significant effect (P < 0.05, P < 0.01) on walking time compared with that of the control group. Compound I had a significant effect on coordinated movement (P < 0.05). Both compounds prolonged the suprathreshold barbiturate induced sleeping time (P < 0.05). The number of sleeping animals increased by 30% and 20% for compounds I and II, respectively, under the subthreshold dose of sodium barbital.