Raw Pinelliae Rhizoma: examination of sedative and hypnotic effects in mice and chemical analysis.

Abstract

Raw "Pinelliae Rhizoma" (RPR) is widely used in Chinese clinics to treat insomnia. This study investigated its underlying sedative and hypnotic mechanisms and main active components. A locomotor activity test was used to evaluate the sedative effects of RPR at three dosages (0.2g/mL, 0.4g/mL, and 0.8g/mL) in mice. Polysomnography was used to assess its ability to improve sleep. Ultra-performance liquid chromatography/time of flight/mass spectrometry (UPLC-TOF-MS) analysis was used to identify the potential active components of RPR. Mice in the RPR groups were less active than mice in the vehicle group; this difference was greatest in the 0.8g/mL RPR group. Compared with the vehicle, 0.8g/mL RPR increased the duration of rapid eye movement (REM) sleep in the dark phase. In addition, the duration of wakefulness in the 0.8g/mL RPR group decreased with increasing durations of nonrapid eye movement (NREM) and REM sleep. Compared with diazepam, 0.8g/mL RPR increased REM sleep duration in both the light and dark phases and increased the number of transitions both from NREM sleep to REM sleep and from REM sleep to wakefulness. A total of 33 RPR constituents, including 15 alkaloids, were identified. The results preliminarily indicated that RPR exerts sedative and hypnotic effects in mice, mainly leading to improvements in REM sleep. These effects are possibly due to the alkaloid constituents of RPR.