ABSTRACT
OBJECTIVE Insomnia is the most fre-quent sleep disorder worldwide and the clinical applica-tion of therapeutic drugs has various adverse effects.In recent years,drugs developed from natural herbs have become potential alternative therapies for insomnia.Nuciferine,one of the main bioactive components obtained from the lotus leaves,has been reported to possess extensive pharmacological activities.However,its hypnotic and sleep regulatory effects have rarely been reported.Hence,this study was intended to investigate the pharma-cological effects of nuciferine and its mechanisms of action in insomnia.METHODS The hypnotic and seda-tive effects of nuciferine were investigated using the eval-uation of locomotor activity test and pentobarbital-induced sleep test in normal and serotonin(5-HT)depletion-induced insomniac mice.Furthermore,the sleep regulatory effects,including sleep time,sleep architecture,and δ-wave power spectral density,were explored using elec-troencephalography/electromyogram(EEG/EMG)-based sleep profiling in normal rats.Finally,the mechanisms of the hypnotic and sedative effects of nuciferine were explored usingin vivoand in silico experiments.RESULTS Nuciferine reduced locomotor activity and prolonged pen-tobarbital-induced sleep time in a dose-dependent man-ner in normal and insomniac model mice.Nuciferine sig-nificantly increased the total sleep time and non-rapid eye movement(NREM)sleep time,inhibited NREM sleep fragmentation,and improved delta power between 0.5 Hz and 1 Hz in normal rats.The results of molecular experiments showed that nuciferine could increase the 5-HT content and 5-HT1A receptor level in the hypothala-mus of insomnia model mice.CONCLUSION This study combined network pharmacological prediction and experi-mental pharmacological techniques to discover the seda-tive-hypnotic effect of nuciferine for the first time Nucif-erine can ameliorate sleep disorder in mice with insom-nia,possibly via serotonergic system.Nuciferine may rep-resent a novel treatment that alleviate the insomnia-like symptoms by modulating 5-HT system.