Design, synthesis, and evaluation of pyranochromene derivatives as membrane targeting antibacterials against Gram-positive bacteria.

The rapid growth of bacterial resistance has created obstacles for the effective treatment with conventional antibiotics, simultaneously posing a major threat to public health. In this study, a class of novel amphipathic pyranochromene derivatives were designed and synthesized by mimicking the amphiphilic characteristics of AMPs. Bioactivity screening identified a lead compound 5a with broad-spectrum antibacterial activity against Gram-positive stains (MICs = 1-4 μg/mL) and low hemolytic toxicity (HC = 111.6 μg/mL). Additionally, compound 5a displayed rapid bactericidal action, and was unlikely to induce bacterial resistance. Mechanistic investigation further demonstrated that compound 5a was able to disrupt the transmembrane potential and increased membrane permeability of S. aureus, which in turn causes leakage of cell contents such as DNA and proteins, ultimately leading to bacterial death. These findings indicated that compound 5a is a promising lead to combat bacterial infection caused by Gram-positive bacteria.