Isolation, characterization, and bioactivity profiling of oxazoline containing madurastatin siderophores from Actinomadura sp.

Chemistry and biology of specialized metabolites produced by Actinomadura

“…155,156 Miaolinolide and miaolienone strongly inhibited the production of lipopolysaccharide-induced tumor necrosis factor (TNF-a) in U937 cells in vitro, with IC 50 values of 0.76 and 0.59 mM, respectively. 156 Actinomadura strain BCC27169 yielded a series of 3-oxyanthranilic acid derivatives (157)(158)(159)(160)(161)(162)(163)(164). These derivatives were associated with three distinct aglycones, which were attached to either 4-O-methylrhamnose or 4-O-methylribopyranoside monosaccharides.…”

“…19). [159][160][161][162][163][164] Initially madurastatins were characterized as aziridine containing peptides. 160,161 Revisiting the NMR data and comparison with siderophores having 2-(2-hydroxyphenyl)oxazoline moieties, together with partial synthesis, suggested the revision of the aziridine to an oxazoline ring.…”

“…162 Similarly, enantiomers of madurastatins D1 (ent-179) and D2 (ent-180) has been reported. 164 Some of the…”

“…Likewise, compounds 190 and 191, despite their structural differences, are both referred to as madurastatin G1. 163,164 To avoid confusion, we have renamed madurastatin E1 from Actinomadura strain RB99, E1-RB99 (185), and the molecule from Actinomadura strain ST100801 E1-ST100801 (186). Similarly, madurastatins G1 were renamed G1-RB99 (190) and G1-ST100801 (191).…”

“…162 Similarly, enantiomers of madurastatins D1 (ent-179) and D2 (ent-180) has been reported. 164 Some of the madurastatins possess moderate activity against Micrococcus luteus 162 and Moraxella catarrhalis 164 but that has been attributed to their iron-chelating mode of action. 164 Two independent studies proposed NRPS biosynthetic gene clusters mad and rene from Actinomadura strains WMMA-1423 and RB99, respectively, to be responsible for the biosynthesis of madurastatins.…”