Neolignanamides, lignanamides, and other phenolic compounds from the root bark of Lycium chinense

Abstract

Seven new neolignanamides (1-7), including two pairs of cis- and trans-isomers, and a new lignanamide (8) were isolated from the EtOAc-soluble fraction of an EtOH extract of the root bark of Lycium chinense, together with 22 known phenolic compounds (9-30), four of which were obtained from the genus Lycium for the first time. Compounds 5, 6, and 7 are unusual dimers having a rare connection mode between the two cinnamic acid amide units, while compounds 6, 7, and 8 are the first naturally occurring dimers derived from two dissimilar cinnamic acid amides. The cinnamic acid amides, neolignanamides, and lignanamides possess moderate radical-scavenging activity against the DPPH (2,2-diphenyl-1-picrylhydrazyl) and superoxide radicals.