Oral Administration of Armillaria mellea Mycelia Promotes Non-Rapid Eye Movement and Rapid Eye Movement Sleep in Rats.

I-Chen Li,Yun Lo,Fang-Chia Chang,Chin-Chu Chen,Ting-Wei Lin,Yih-Min Jiang,Tung-Yen Lee,Yu-Hsuan Kuo

doi:10.3390/jof7050371

Abstract

The present study aimed to explore whether water and ethanol extracts of Armillaria mellea mycelia produce sedative and hypnotic effects in rats. Male Sprague–Dawley rats were surgically implanted with two electroencephalogram electrodes on the skull and an electromyogram electrode on neck muscle to evaluate the alterations in rapid eye movement (REM) and non-REM (NREM) sleep after oral administration of the water and ethanol extracts. Following post-surgical recovery, thirty-six rats were randomly divided into four treatment groups and two control groups. They were treated orally with vehicle, 75 and 150 mg/kg doses of water and ethanolic extracts 15 min prior to the onset of dark (active) period. Electroencephalography results showed that the low dose of A. mellea mycelia water extract increased REM sleep time while the high dose enhanced both REM and NREM sleep times during the subsequent light (rest) period. On the other hand, although the low dose of A. mellea mycelia ethanolic extract did not alter both NREM sleep and REM sleep during the dark and light periods, the high dose increased both REM and NREM sleep during the light periods in naive rats. The HPLC-DAD analyses of both extracts allowed the identification of GABA and seven sesquiterpenoids. Based on these findings, the present study showed for the first time that water and ethanolic extracts of A. mellea mycelia, containing a source of biologically active compounds, could increase both NREM sleep and REM sleep during the rest period and may be useful for the treatment of insomnia.

Highlights

Results indicated that non-rapid eye-movement (NREM) sleep was not altered during both the 12 h dark period and 12 h light period; rapid eye-movement (REM) sleep was significantly increased during the 12 h light period, especially the first five hours of the light period, when rats received 75 mg/kg water-extracted A. mellea (Figure 1A)
The percentage of time spent in REM sleep increased from 12.08 ± 0.91% obtained from vehicle to 15.89 ± 1.29% during the 12 h light period and it increased from 11.73 ± 1.54% to
(150 mg/kg) water-extracted A. mellea was given before the dark period, NREM sleep significantly increased during the 12 h light period, especially the hours between 18–20 (Figure 1A)

Summary

Introduction

Sleep is essential in sustaining healthy physical and mental health. It has important effects in many vital physiologic functions, such as development, energy conservation, brain waste clearance, cognitive support, hormonal balance and immune function modulation [1]. Sleep occurs in four stages that include non-rapid eye-movement (NREM) sleep (N1 to N3). Rapid eye-movement (REM) sleep, which constitutes 75 and 25 percent, respectively, of total time spent in sleep [2]. Throughout sleep, NREM sleep and REM sleep alternate

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