Phenolic constituents of Convolvulus dorycnium L. flowers

The new phenolic metabolites 3-(2-butoxy-3-caffeoyl-1-hydroxycyclobutyl)-3-hydroxypropanoic acid, named as dorycnic acid (1), and 4-O-(4′-carboxymethyl-2′,4′,6′-trihydroxycyclohexyl)-vanillic acid (2), together with scopolin (3), kaempferol 3-rutinoside (4), scopoletin (5), and methyl caffeate (6) were isolated from the flowers of Convolvulus dorycnium L. Their structures were elucidated on the basis of spectroscopic evidence, and comparison with authentic samples. Compounds 1–6 were evaluated for their antioxidative activity in the 1,1-diphenyl-2-picrylhydrazyl assay, where the caffeic acid derivative 1 proved to possess the most potent scavenging activity, with an IC₅₀ value of 31.5 μM.