Institute of Botany, ANAS
The diurnal accumulation dynamics of free and glycosylated flavonoids in leaves and flowers of the Crataegus
caucasica C.Koch. has been investigated. It was established that the content of flavonoids in leaves and
flowers changed significantly during a day. In leaves as well as in flowers changes of the contents of flavonoids
were accompanied by two maximums at 12 and 18, and by minimum at 24 o'clock. Diurnal changes of
contents of the flavonoids were mainly conditioned by fluctuations of the contents of quercetin derivatives.
The distinctive metabolic ways of the biosynthesis of free and glycosylated flavonoids were revealed. The
content of flavonoids in leaves and flowers depends on a plant organ, a phase of development and weather
conditions of the vegetative period.