Bioactive Piperazic Acid-Bearing Cyclodepsipeptides, Lydiamycins E–H, from an Endophytic <i>Streptomyces</i> sp. Associated with <i>Cinnamomum cassia</i>

Abstract

A chemical investigation of the endophytic <i>Streptomyces</i> sp. HBQ95, associated with the medicinal plant <i>Cinnamomum cassia</i> Presl, enabled the discovery of four new piperazic acid-bearing cyclodepsipeptides, lydiamycins E-H (<b>1</b>-<b>4</b>), and one known compound (lydiamycin A). Their chemical structures, including absolute configurations, were defined by a combination of spectroscopic analyses and multiple chemical manipulations. Lydiamycins F-H (<b>2</b>-<b>4</b>) and A (<b>5</b>) exhibited antimetastatic activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.