Mersaquinone, A New Tetracene Derivative from the Marine-Derived Streptomyces sp. EG1 Exhibiting Activity against Methicillin-Resistant Staphylococcus aureus (MRSA)

Abstract

New antibiotics are desperately needed to overcome the societal challenges being encountered with methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). In this study, a new tetracene derivative, named Mersaquinone (<b>1</b>), and the known Tetracenomycin D (<b>2</b>), Resistoflavin (<b>3</b>) and Resistomycin (<b>4</b>) have been isolated from the organic extract of the marine <i>Streptomyces</i> sp. EG1. The strain was isolated from a sediment sample collected from the North Coast of the Mediterranean Sea of Egypt. The chemical structure of Mersaquinone (<b>1</b>) was assigned based upon data from a diversity of spectroscopic techniques including HRESIMS, IR, 1D and 2D NMR measurements. Mersaquinone (<b>1</b>) showed antibacterial activity against methicillin-resistant <i>Staphylococcus aureus</i> with a minimum inhibitory concentration of 3.36 μg/mL.