Leaf flavonoids in Cotoneaster wilsonii (Rosaceae) from the island Ulleung-do, Korea

Abstract

The leaf flavonoids of Cotoneaster wilsonii, an endemic shrub to the island Ulleung-do in East Sea of Korea, were characterized and compared with flavonoids in some eastern Asian Cotoneaster species. The highly specialized taxa belonging to sect. Cotoneaster ( sensu Yü) including C. wilsonii produced a mixture of flavone O- and C-glycoside and flavonol O-glycosides, including isorhamnetin glycosides. The morphologically similar species, C. multiflorus and C. hebephyllus of central China and C. wilsonii of Korea had similar flavonoid profiles. In addition, C. tenuipes, C. zabelii, and C. dielsianus (sect. Cotoneaster, ser. Integerrimi) had similar flavonoid patterns to taxa in the C. multiflorus complex (sect. Cotoneaster, ser. Multiflori). This indicated that the chemical data cut across Yü’s serial treatment within section Cotoneaster. Earlier studies showed that there were few absolute differences between many of the other woody plants growing on this island and on those on the Korean peninsula and mainland China, or the Japanese archipelago. C. wilsonii appears to be another example in which no change in chemistry or morphology has occurred. Many of the woody plants on this island are very recently derived and their progenitors were historically more widely and continuously distributed in eastern Asia.