Sedative and hypnotic effects of the saponins from a traditional edible plant Liriope spicata Lour. in PCPA-induced insomnia mice.

Liriope spicata Lour., a species listed in the catalogue of 'Medicinal and Edible Homologous Species', is traditionally used for the treatment of fatigue, restlessness, insomnia and constipation. This study is aimed to evaluate the sedative and hypnotic effect of the saponins from a natural plant L. spicata Lour. in vivo. The total saponin (LSTS) and purified saponin (LSPS) were extracted from L. spicata , followed by a thorough analysis of their major components using the HPLC-MS. Subsequently, the therapeutic efficacy of LSTS and LSPS was evaluated by the improvement of anxiety and depression behaviors of the PCPA-induced mice. LSTS and LSPS exhibited similar saponin compositions but differ in their composition ratios, with liriopesides-type saponins accounting for a larger proportion in LSTS. Studies demonstrated that both LSTS and LSPS can extend sleep duration and immobility time, while reducing sleep latency in PCPA-induced mice. However, there was no significant difference in weight change among the various mice groups. Elisa results indicated that the LSTS and LSPS could decrease levels of NE, DA, IL-6, and elevate the levels of 5-HT, NO, PGD2 and TNF-α in mice plasma. LSTS enhanced the expression of neurotransmitter receptors, while LSPS exhibited a more pronounced effect in regulating the expression of inflammatory factors. In conclusion, the saponins derived from L. spicata might hold promise as ingredients for developing health foods with sedative and hypnotic effects, potentially related to the modulation of serotonergic and GABA A ergic neuron expression, as well as immunomodulatory process. L. spicata is a health drink and functional food that consumed in China for many years, which is considered to have function with nourishing Yin, clearing away heartburn, calming the nerves. Our results showed the saponins LSTS and LSPS administration could significantly increase the sleep duration time and immobility time, and decrease the sleep latency of the PCPA induced depression mice. LSTS and LSPS could decrease the NE, DA, IL-6 amount, and increase the 5-HT, NO, PGD2 and TNF-α level in mice plasma. LSTS could significantly improve the expression of neurotransmitters receptors (5HT-1A, 5HT-2A, GABAAα2, GABAAα3 and GABAAα5), and the LSPS showed better effect of regulating the inflammatory factors expression. This work proved that the major component saponins could relieve the spirit of PCPA induced mice, indicating that the saponins from L. spicata are potential functional food with spirit-quieting effect. [Display omitted] [ABSTRACT FROM AUTHOR]