The flavonoid myricetin reduces nocturnal melatonin levels in the blood through the inhibition of serotonin N-acetyltransferase.

The flavonoid myricetin reduces nocturnal melatonin levels in the blood through the inhibition of serotonin N-acetyltransferase. Biochem Biophys Res Commun. 2013 Sep 25; Authors: Shin JC, Jung HY, Harikishore A, Kwon OD, Yoon HS, Kim KT, Choi BH Abstract Melatonin is secreted during the hours of darkness and is thought to influence the circadian and seasonal timing of a variety of physiological processes. AANAT, which is expressed in the pineal gland, retina, and various other tissues, catalyzes the conversion of serotonin to N-acetylserotonin and is the rate-limiting enzyme in the biosynthetic pathway of melatonin. The compounds that modulate the activity of AANAT can be used to treat patients with circadian rhythm disorders that are associated with specific circadian rhythm alterations, such as shift work disorder. In the present study, we screened modulators of AANAT activity from the water extracts of medicinal plants. Among the 267 tested medicinal plant extracts, Myricae Cortex (Myrica rubra), Perillae Herba (Perilla sikokiana), and Eriobotryae Folium (Eriobotrya japonica) showed potent inhibition of AANAT activity. Myricetin (5,7,3',4',5'-pentahydroxyflavonol), a main component of the Myricae Cortex, strongly inhibited the activity of AANAT and probably block the access to the substrate by docking to the catalytic residues that are important for AANAT activity. Myricetin significantly decreased the nocturnal serum melatonin levels in ra...
Source: Biochemical and Biophysical Research communications - Category: Biochemistry Authors: Tags: Biochem Biophys Res Commun Source Type: research