Maklamicin, an Antibacterial Polyketide from an Endophytic Micromonospora sp.

Abstract

A new spirotetronate-class polyketide, maklamicin (1), was isolated from the culture extract of an endophytic actinomycete of the genus Micromonospora. The structure and relative configuration of 1 were elucidated by interpretation of NMR and other spectroscopic data, and the absolute configuration was determined using the modified Mosher method. Maklamicin (1) showed strong to modest antimicrobial activity against Gram-positive bacteria.

Nomimicin, a new spirotetronate-class polyketide from an actinomycete of the genus Actinomadura

“…Analysis of 1 H and 13 C NMR, and HSQC data established three oxygenated quaternary sp 2 carbons, seven sp 2 carbons (five are proton-bearing), three quaternary sp 3 carbons (one is oxygen-bearing), seven sp 3 methines (two are oxygen-bearing), five sp 3 methylenes and five methyl groups ( Table 1). The UV spectrum of 1 was closely similar to that of maklamicin 7 (Figure 1), a spirotetronate polyketide that we recently discovered from a Micromonospora strain, suggesting the presence of a tetronic acid functionality in this molecule. This was supported by the 13 3) and C-24 (d C 204.5) that closely matched those reported for this structure in maklamicin.…”

“…2 Among the nonStreptomyces species, Micromonospora is the leading producer of secondary metabolites, including polyketides, peptides and glycosides, whereas Actinomadura is known as a producer of chemically and biologically unique polyketides such as antitumor enediynes, 3 mannose-binding quinone glycosides with antifungal and anti-HIV activities 4 and anticoccidial polyethers, 5 accounting for up to 350 compounds reported as of 2005. 2 During our continuing investigation on the metabolites from actinomycetes of nonStreptomyces group, 6,7 a new spirotetronate antibiotic of polyketide origin, nomimicin (1, Figure 1), was isolated from the culture extract of Actinomadura sp. TP-A0878.…”

Endophytic Nocardiopsis sp. from Zingiber officinale with both antiphytopathogenic mechanisms and antibiofilm activity against clinical isolates

“…Streptomyces isolated as endophyte from maize was described to have antimicrobial activity against S. aureus, Micrococcus luteus, B. subtilis and the yeast C. albicans (Araújo et al 2000). Also, endophytic Micromonospora is known to have the ability to produce a new spirotetronate-class polyketide, maklamicin (1) (Igarashi et al 2011). This compound showed strong to modest antimicrobial activities against M. luteus, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Enterococcus faecalis and was slightly active against C. albicans.…”

Simamycin (5′-O-geranyluridine): a new prenylated nucleoside from Streptomyces sp.

“…Biological assays. Adipocyte differentiation assay 10 , antimicrobial assay 14 and cytotoxic assay 14 were carried out according to the procedures previously described.…”