Determination of hydroxycinnamic acids present in Rhododendron species.

Hydroxycinnamates including free hydroxycinnamic acids and their chlorogenic acid derivatives and glycosides have been profiled in leaf extracts of 98 Rhododendron species using LC-MS techniques. In total, 69 hydroxycinnamic acid derivatives were identified in the leaves of 98 Rhododendron species. Some derivatives serve as unique phytochemical marker for a single species, whereas other compounds are limited to certain subgenera. The distribution of compounds among six different subgenera of Rhododendron was studied using PCA and PLS-DA. This contribution presents data that provide unique metabolomic insight in the distribution of a class of secondary metabolites within a large selection of species from the botanically diverse plant genus Rhododendron.