Bioactive natural prodiginine/prodigiosin pigments from the deep-sea-derived actinobacterium Streptomyces coelicoflavus

The phylum Actinomycetota represents one of the most extensive taxonomic groups within the domain Bacteria , with Streptomyces being one of its most prominent genera regarding its biosynthetic potential and biotechnological applications. An interesting group of bioactive compounds derived from various bacterial phyla, including Actinomycetota , are prodiginines, including prodigiosin—red-pigmented molecules with anticancer and antibacterial activities [ 1 ]. While initial studies hint at its bioactive promise [ 2 ], the species under study, Streptomyces coelicoflavus , remains chemically underexplored, especially regarding its pigment production. Herein, we present a workflow for the successful detection, isolation and structural elucidation of bioactive natural pigments of the prodiginine/ prodigiosin family from the intensely colored biomass of the marine actinobacterium S. coelicoflavus . The extracts were acquired through a multi-step ultrasound-assisted extraction of the biomass originating from liquid cultures, and then subjected to MPLC fractionation. Identification of the compounds present in the crude extract was carried out by a GC–MS analysis. Two major pigmented compounds were assigned by comparing their mass spectra to those found in reference libraries and were additionally structurally elucidated via NMR as undecylprodigiosin (=undecylprodiginine) and metacycloprodigiosin (=metacycloprodiginine) ([ Fig 1 ]). Fig. 1 The structures of bioactive pigments isolated from Streptomyces coelicoflavus . Acknowledgements EU’s Horizon2020 Research and Innovation Programme (Grant Agreement No. 101000794). Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany