Design, Synthesis, and Mechanism of Novel 9-Aliphatic Amine Tryptanthrin Derivatives against Phytopathogenic Bacteria.

Taking inspiration from the use of natural product-derived bactericide candidates in drug discovery, a series of novel 9-aliphatic amine tryptanthrin derivatives were designed, synthesized, and evaluated for their biological activity against three plant bacteria. The majority of these compounds exhibited excellent antibacterial activity in vitro. Compound exhibited a significantly superior bacteriostatic effect against pv (), pv (), and pv () with final corrected EC values of 0.769, 1.29, and 15.5 μg/mL, respectively, compared to the commercial pesticide thiodiazole copper which had EC values of 58.8, 70.9, and 91.9 μg/mL. Preliminary mechanism studies have demonstrated that is capable of altering bacterial morphology, inducing reactive oxygen species accumulation, promoting bacterial cell apoptosis, inhibiting normal cell growth, and affecting cell membrane permeability. Moreover, in vivo experiments have substantiated the effectiveness of as a therapeutic and defensive agent against the citrus canker. The proteomic analysis has unveiled that the major disparities are located within the bacterial secretion system pathway, which hinders membrane transportation. These discoveries imply that could be an auspicious prototype for developing antiphytopathogenic bacterial agents.