One new pyrrolosesquiterpene 1 was isolated from the cultures of the soil actinomycete Streptomyces sp. Hd7–21. Its structure
was elucidated by extensive spectroscopic analyses including MS and one-dimensional and two-dimensional NMR data.
Compound 1 showed moderate cytotoxic activity against a panel of human cancer cell lines.
The Journal of Antibiotics (2014) 67, 415–417; doi:10.1038/ja.2014.8; published online 19 February 2014
Keywords: actinomycetes; cultures; pyrrolosesquiterpene
INTRODUCTION
Natural products are excellent sources of lead compounds to
develop new drugs for the treatment of diseases.1 This is
particularly evident in the treatment of cancers, in which more
than 60% of the drugs are of natural origin.2 Hence, newly
identified natural compounds with anticancer activity could
represent a new tool for cancer therapy. Actinomycetes are
widely distributed in nature, and are typically useful in the
pharmaceutical industry for their seemingly unlimited capacity
to produce secondary metabolites with diverse chemical structures
and biological activities.3
Pyrroles have been incorporated into a variety of natural
products, yet their appearance among terpenes is rare. To our
knowledge, the only previously described pyrroloterpene natural
products are pyrrolostatin4 and glyciapyrroles A–C.5 As part of our
ongoing search for biologically active secondary metabolites,6–9
streptomyces sp. Hd7–21 from the soil sample collected in DaXingAnling
virgin forest came to our attention as it displayed an
interesting chemical profile from our initial LC–MS analysis. This
prompted us to investigate the chemical diversity of this strain
which led to the isolation of one new pyrrolosesquiterpene 1. We
herein report the fermentation, isolation, structure elucidation and
the biological activity of the compound.