Daylily (Hemerocallis fulva Linn.) flowers improve sleep quality in human and reduce nitric oxide and interleukin-6 production in macrophages.

The flowers of daylily (Hemerocallis fulva Linn.) have been used as vegetable and medicinal herb for thousands of years in Taiwan and eastern Asia. Daylily flowers have been demonstrated to exert several biomedical properties. In this study, we provided the evidences show that daylily flowers exert anti-inflammatory activity in vitro and improved the sleep quality in vivo. We demonstrated that adult volunteers received water extract of daylily flowers improved sleep quality, sleep efficiency and daytime functioning, while sleep latency was reduced, compared to the adult volunteers received water. In addition, we demonstrated that aqueous and ethanol extracts of daylily flowers inhibited nitric oxide and interleukin-6 production in lipopolysaccharide-activated macrophages. Furthermore, the quantitative high performance liquid chromatography-based analysis showed the rutin content of the aqueous extract, ethanolic extract, ethyl acetate fractions of ethanolic extract, and water fractions of ethanolic extract were 7.27, 23.30, 14.71, and 57.43 ppm, respectively. These results indicate that daylily flowers have the potential to be a nutraceutical for improving inflammatory-related diseases and sleep quality in the future.