Design, Synthesis,\nand Biological Evaluation of Novel\nQuinoline Derivatives against Phytopathogenic Bacteria Inspired from\nNatural Quinine Alkaloids

A series of 2-(trifluoromethyl)-4-hydroxyquinoline derivatives\nwere designed and synthesized with introduction of the antibacterial\nfragment amino alcohols, and their antibacterial activity against\nplant phytopathogenic bacteria was evaluated for the development of\nquinoline bactericides. It is worth noting that compound <b>Qa5</b> exhibited excellent antibacterial activity <i>in vitro</i> with a minimum inhibitory concentration (MIC) value of 3.12 μg/mL\nagainst Xanthomonas oryzae (<i>Xoo</i>). Furthermore, <i>in vivo</i> assays demonstrated\nthat the protective efficacy of <b>Qa5</b> against rice bacterial\nblight at 200 μg/mL (33.0%) was superior to that of the commercial\nagent bismerthiazol (18.3%), while the curative efficacy (35.0%) was\ncomparable to that of bismerthiazol (35.7%). The antibacterial mechanisms\nof <b>Qa5</b> indicated that it affected the activity of bacteria\nby inducing intracellular oxidative damage in <i>Xoo</i> and disrupting the integrity of the bacterial cell membrane. The\nabove results demonstrated that the novel quinoline derivative <b>Qa5</b> possessed excellent <i>in vitro</i> and <i>in vivo</i> antibacterial activity, indicating its potential\nas a novel green agricultural antibacterial agent.