Antimicrobial Macrolide Levantilide D from Rare Marine Micromonospora sp.

Introduction: One new levantilide D (2) with a 20-membered macrolide, along with one known levantilide C (1), was isolated from a rare marine actinomycetes Micromonospora sp. (FIMYZ52). Method: The structural elucidation of the compounds was based on integrated analyses involving 1D and 2D NMR spectroscopy and HR-ESI-MS. Result: The relative and absolute configurations of compounds 1 and 2 were ascertained by integrating multispectral ROESY and NOESY information from analogs in conjunction with theoretical TDDFT-ECD calculations. Levantilide D (2) exhibited antibacterial activity against Staphylococcus aureus. Conclusion: A plausible biosynthetic pathway of the macrolide compounds (1-2) was proposed.