Design, synthesis, and evaluation of novel 3-(piperazin-1-yl) propan-2-ol-modified carbazole derivatives targeting the bacterial membrane

Grain of high yield and quality is needed worldwide due to the needs of a rapidly increasing human population. However, diseases caused by some stubborn types of phytopathogenic bacteria can limit the health and yields of crops. Even worse, conventional commercial bactericides have limited efficacy against such diseases. Therefore, exploring some efficacious bactericidal alternatives is urgently needed. In this work, a new type of 3-(piperazin1-yl)propan-2-ol modified carbazole derivatives was synthesized and assessed for their bactericidal activity. Among them, compound B16 was the optimal active molecule, giving the EC50 values of 3.11 (Xanthomonas oryzae pv. oryzae), 3.20 (Xanthomonas axonopodis pv. citri) and 3.54 mu g/mL (Pseudomonas syringae pv. actinidiae). Pot experiments revealed compound B16 to be able to control rice bacterial leaf blight. Some biochemical assays illustrated that our designed compounds could destroy the integrality of bacterial cell membranes and thereby leading to leaking the intracellular protein. These findings may be regard as a reference for the design of novel membrane-targeting antimicrobial agents for managing stubborn plant bacterial diseases.