Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

Abstract

Three new tetronate-class polyketides, nomimicins B, C, and D, along with nomimicin, hereafter named nomimicin A, were isolated from the culture extract of Actinomadura sp. AKA43 collected from floating particles in the deep-sea water of Sagami Bay, Japan. The structures of nomimicins B, C, and D were elucidated through the interpretation of NMR and MS analytical data, and the absolute configuration was determined by combination of NOESY/ROESY and ECD analyses. Nomimicins B, C, and D showed antimicrobial activity against Gram-positive bacteria, Kocuria rhizophila and Bacillus subtilis, with MIC values in the range of 6.5 to 12.5 μg/mL. Nomimicins B and C also displayed cytotoxicity against P388 murine leukemia cells with IC50 values of 33 and 89 μM, respectively.

Catellatolactams A–C, Plant Growth-Promoting Ansamacrolactams from a Rare Actinomycete of the Genus Catellatospora

“…To the best of our knowledge, eight metabolites are distantly related (Figure 8), which are Q-1047R from Pseudonocardia, 18 tetrapetalones A−D and ansaetherone produced by the same Streptomyces strain, 19,20 and cebulactams A1 and A2 from marine obligate Saccha-ropolyspora. 21 Thus, discovery of catellatolactams A−C (1−3), together with our previous studies, [6][7][8]22,23 demonstrates a strategic advantage of investigating underexplored rare actinomycetal genera as a source of unprecedented molecular architectures.…”

Marine natural products

“…This molecule showed a broad spectrum of antifungal activity against several plant fungal pathogens as well as pathogenic yeasts with MIC values ranging from 2–10 μg mL −1 . 3 New antibacterial tetronate-based polyketide derivatives, nomimicins A–D 2–5 , were identified from a fermentation culture of an Actinomadura strain, 4 whilst chemical examination of an Aquimarina sp. bioactive broth yielded caprolactin C 6 , which, along with its enantiomer ( ent -caprolactin C), were synthesised.…”

Antibacterial Spirotetronate Polyketides from an Actinomadura sp. Strain A30804

“…Subsequently nomimicins B-D, new tetronate-class polyketides were also isolated from a marine-derived actinomycete of the genus Actinomadura . These compounds showed antimicrobial activities [ 10 , 11 ].…”