Depsidomycins B and C: New Cyclic Peptides from a Ginseng Farm Soil-Derived Actinomycete

Abstract

LC/MS-based chemical profiling of a ginseng farm soil-derived actinomycete strain, Streptomyces sp. BYK1371, enabled the discovery of two new cyclic heptapeptides, depsidomycins B and C (1 and 2), each containing two piperazic acid units and a formyl group at their N-terminus. The structures of 1 and 2 were elucidated by a combination of spectroscopic and chemical analyses. These new compounds were determined to possess D-leucine, D-threonine, D-valine, and S-piperazic acid based on the advanced Marfey's method and a GITC (2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate) derivatization of their hydrolysates, followed by LC/MS analysis. Depsidomycins B and C displayed significant antimetastatic activities against metastatic breast cancer cells (MDA-MB-231).