Flavonoids from mulberry leaves exhibit sleep-improving effects via regulating GABA and 5-HT receptors

Mulberry leaf (Folium Mori) is a dried leaf of the dicotyledonous mulberry tree and is a homologous food and medicine. Treating insomnia with it is a common practice in traditional Chinese medicine. But still, its potential sleep-improving mechanism remains to be elucidated.

Potential bioactive components and mechanisms of the sleep-improving effect of purified flavone from mulberry leaves (MLF) were explored through in vivo experiments, network pharmacology analysis, and molecular experimental validation.

The mice model was established by pentobarbital sodium induction to evaluate the sleep-improving effect of MLF. The MLF's chemical composition was identified through a liquid chromatograph quadrupole time-of-flight mass spectrometer (Q-TOF LC/MS) to elucidate its sleep-improving active ingredient. At last, the underlying mechanism of MLF's sleep-improving effect was elucidated through neurotransmitter detection (ELISA), network pharmacology analysis, and molecular experimental validation (quantitative real-time PCR and western blotting).

MLF could dramatically reduce sleep latency by 35%, prolong sleep duration by 123%, and increase the sleep rate of mice through increasing γ-aminobutyric acid (GABA) and serotonin (5-HT) release in serum, hypothalamus, and hippocampus. Q-TOF LC/MS identified 17 flavonoid components in MLF. Network pharmacological analysis suggested that the key sleep-improving active ingredients in MLF might be quercetin, kaempferol, morin, and delphinidin. The key path for MLF to improve sleep might be the tryptophan metabolism and neuroactive ligand-receptor interaction, and the key targets might be gamma-aminobutyric acid type A receptor subunit alpha2 Gene (GABRA2) and serotonin 1A (5-HT1A) receptors.

MLF has shown significant sleep-improving effects in mice and may take effect through regulating the GABA and 5-HT receptors.