Caffeoyl-D-Glucaric Acid Derivatives in the Genus Gnaphalium (Asteraceae: Gnaphalieae)

Abstract

A chemosystematic survey was carried out to specify whether leontopodic acid and leontopodic acid B, two unique caffeoyl-D-glucaric acid derivatives, recently identified in the emblematic alpine edelweiss (Leontopodium alpinum Cass.) are also found in members of the genus Gnaphalium from the Alps. Gnaphalium is closely related to Leontopodium and both genera are assigned to the Gnaphaliinae subtribe (Asteraceae, Gnaphalieae). In all investigated Gnaphalium species, G. hoppeanum W.D.J.Koch, G. norvergicum Gunnerus, G. supinum L., G. sylvaticum L., and G. uliginosum L., both leontopodic acid and leontopodic acid B were detected. Moreover, a number of related compounds were detected by HPLC/MS and their assumed structures are discussed. The chemosystematic data reported here are of interest to explore new sources for the biologically active compounds leontopodic acid and leontopodic acid B and they also hint to the occurrence of novel caffeoyl-D-glucaric acid derivatives in Gnaphalium not detected in Leontopodium, yet.