Pronounced activity of aromatic selenocyanates against multidrug resistant ESKAPE bacteria

Abstract

Selenocyanates represent an interesting class of organic selenium compounds. Due to their similarity with better known natural (iso-)thiocyanates, they promise high biological activity and may also be metabolized to other Reactive Selenium Species (RSeS), such as selenols, diselenides and seleninic acids. Thirteen arylmethyl selenocyanates (1–13) have been synthesized and evaluated for potential antimicrobial, nematicidal and cytotoxic activity. The compounds exhibit pronounced antimicrobial activity against various strains of Gram-positive and Gram-negative bacteria and yeasts, including multidrug resistant strains. The results obtained so far demonstrate that these arylmethyl selenocyanates are also non-mutagenic and have limited cytotoxicity against human cells. Here, benzyl selenocyanate (1) represents the most active anti-ESKAPE agent, with potent activity against multidrug resistant MRSA strains (HEMSA 5) – with a competitive MIC value of just 0.76 μg mL⁻¹ (3.88 μM), whereas it exhibits low(er) cytotoxicity (IC₅₀ = 31 μM) and no mutagenicity against mammalian cells. Due to this selective antimicrobial activity, aromatic selenocyanates may provide an interesting lead in the development of antimicrobial agents, particularly in the context of drug resistance.