Provenance and temporal variations in selected flavonoids in leaves of Cyclocarya paliurus

Cyclocarya paliurus is a well-known multiple function plant in China. To reveal the provenance variation of selected flavonoids in leaves of C. paliurus and changes of their level during the growing season, twelve provenances were grown in a field trial and sampled five times at approximately 1 month intervals. The levels of flavonoids varied significantly in leaves of C. paliurus from different provenances, and isoquercitrin represented the largest component of the selected compounds, followed by kaempferol and quercetin. The growing season also significantly affected the concentration of total flavonoids and its composition. In most cases, the greatest concentration was observed in July and October, showing a bimodal temporal variation pattern. Results not only demonstrated that leaves of C. paliurus exhibited commendably higher levels of quercetin, kaempferol and isoquercitrin, but also provided a basis for breeding strategies, selecting superior provenances, and choosing harvesting time for producing specific flavonoids for the food industry.