Phenylpropanoid amides from the roots of Solanum melongena L. (Solanaceae)

Phytochemical investigation of the roots of Solanum melongena L. led to the isolation of 16 phenylpropanoid amides (1–16). Their structures were identified by analysis of spectroscopic data and comparison with those reported in the literature. This is the first report of the natural occurrence of N-trans-sinapoyloctopamine (9) and N-trans-caffeoyloctopamine (10). N-trans-feruloylnoradrenline (12) and N-cis-feruloylnoradrenline (16) were isolated from the genus Solanum for the first time. Four compounds including 3-(4-hydroxyphenyl)-N-[2-(4-hydroxyphenyl)-2-methoxyethyl] acrylamide (5), 3-(4-hydroxy-3-methoxyphenyl)-N-[2-(4-hydroxyphenyl)-2-methoxyethyl] acrylamide (6), N-trans-p-coumaroylnoradrenline (11), and N-cis-p-coumaroyloctopamine (15) were firstly reported from S. melongena. The chemotaxonomic significance of these compounds was summarized.