Pinelliae Rhizoma Praeparatum Cum Alumine Extract: Sedative and Hypnotic Effects in Mice and Component Compounds

Abstract

Pinelliae Rhizoma Praeparatum Cum Alumine (PRPCA) is useful for eliminating dampness and phlegm in clinical settings, targeting the main mechanisms of insomnia as defined in traditional Chinese medicine. However, little is known regarding the sedative and hypnotic effects of PRPCA. In the present study, we examined the sedative effects of PRPCA via a locomotor activity test and aimed to determine the most appropriate concentration of PRPCA for achieving these effects. The strongest sedative effects were observed at a PRPCA concentration of 0.45 g/ml. In addition, we investigated the hypnotic effects of PRPCA and its role in promoting sleep via sleep monitoring and vigilance state analysis. PRPCA increased rapid eye movement (REM) sleep and non-REM (NREM) sleep while decreasing wakefulness. In addition, PRPCA decreased the number of bouts of wakefulness (16-32 s and 32-64 s) and increased the number of bouts of NREM sleep (128-256 s). Furthermore, we identified a total of 32 component compounds via chromatography and mass spectrometry. Hence, the current work provides valuable information regarding the sedative and hypnotic effects of PRPCA and its regulatory mechanisms in promoting sleep.

Figure 1

Locomotor activity following intragastric administration. White, gray, horizontal black/white, vertical black/white, and black circles represent the profiles for the SWFI, PRPCA 1, PRPCA 2, PRPCA 3, and DZP group, respectively. SWFI: sterile water for injection; PRPCA: Pinelliae Rhizoma Praeparatum Cum Alumine; DZP: diazepam.

Figure 2

Sleep-stage distributions produced by SWFI, PRPCA, and DZP. (a) Time course of changes in wakefulness, REM sleep, and NREM sleep. Each circle represents the mean hourly amount of time spent in each stage. The horizontal open and filled bars on the X-axes indicate the 12-h light and 12-h dark periods, respectively. (b) Total time spent in wakefulness, REM sleep, and NREM sleep during the 12-h light and 12-h dark periods. White, gray, and black circles/bars represent the profiles for the SWFI, PRPCA, and DZP groups, respectively. Data are expressed as the mean ± SEM; ^#P<0.05: PRPCA vs. SWFI; ∗P<0.05: PRPCA vs. DZP; ^∆∆P<0.01 and ^∆P<0.05: SWFI vs. DZP as assessed using ANOVA followed by the LSD test. SWFI: sterile water for injection; PRPCA: Pinelliae Rhizoma Praeparatum Cum Alumine; DZP: diazepam; REM: rapid eye movement; NREM: nonrapid eye movement; ANOVA: analysis of variance: LSD: least significant difference.

Figure 3

Bouts of wakefulness and NREM sleep during the dark period. White, gray, and black bars show the profiles for the SWFI, PRPCA, and DZP groups, respectively. The negative time values on the X-axis represent the following periods, respectively: 0–16 s, 16–32 s, 32–64 s, 64–128 s, 128–256 s, 256–512 s, 512–1024 s, and 1024–2048 s. Data are expressed as the mean ± SEM; ^#P<0.05: PRPCA vs. SWFI; ^∆P<0.05 SWFI vs. DZP as assessed using ANOVA followed by the LSD test. NREM: nonrapid eye movement; SWFI: sterile water for injection; PRPCA: Pinelliae Rhizoma Praeparatum Cum Alumine; DZP: diazepam; ANOVA: analysis of variance; LSD: least significant difference.

Figure 4

Extracted ion chromatogram of compounds in PRPCA identified via UPLC/Q-TOF-ESI/MS. (a) Extracted ion chromatogram in positive mode (ESI+). (b) Extracted ion chromatogram in negative mode (ESI–). PRPCA: Pinelliae Rhizoma Praeparatum Cum Alumine; UPLC: ultra-performance liquid chromatography; Q-TOF: quadrupole time-of-flight; ESI: electrospray ionization; MS: mass spectrometry.