Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands.
Department of Chemical Engineering, Engineering and Technology Institute Groningen, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
Chempluschem. 2024 Jun;89(6):e202300616. doi: 10.1002/cplu.202300616. Epub 2024 Feb 27.
Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri, is one of the main threats to citrus fruit production. Several phenolic compounds active against X. citri have been described in recent years. Benzene-1,2,4-triol is a bio-based phenolic compound that has shown high potential as a scaffold for the synthesis of new anti-X. citri compounds. However, benzene-1,2,4-triol is prone to oxidative dimerization. We evaluated the antibacterial activity of benzene-1,2,4-triol, its oxidized dimers, and analogous compounds. Benzene-1,2,4-triol has a low inhibitory concentration against X. citri (0.05 mM) and is also active against other bacterial species. Spontaneous formation of benzenetriol dimers (e. g. by contact with oxygen in aqueous solution) reduced the antimicrobial activity of benzenetriol solutions. Dimers themselves displayed lower antibacterial activity and where shown to be more stable in solution. Unlike many other phenolic compounds with anti-X. citri activity, benzene-1,2,4-triol does not act by membrane permeabilization, but seems to limit the availability of iron to cells. Benzene-1,2,4-triol is widely recognized as toxic - our results indicate that the toxicity of benzene-1,2,4-triol is largely due to spontaneously formed dimers. Stabilization of benzene-1,2,4-triol will be required to allow the safe use of this compound.
柑桔溃疡病由黄单胞菌柑橘亚种引起，是柑桔果实生产的主要威胁之一。近年来，已经描述了几种对 X. citri 有活性的酚类化合物。苯-1,2,4-三醇是一种生物基酚类化合物，作为合成新型抗 X. citri 化合物的支架显示出很高的潜力。然而，苯-1,2,4-三醇容易发生氧化二聚化。我们评估了苯-1,2,4-三醇、其氧化二聚体和类似化合物的抗菌活性。苯-1,2,4-三醇对 X. citri 的抑制浓度很低（0.05mM），对其他细菌也有活性。苯-1,2,4-三醇在水溶液中与氧气接触会自发形成苯三醇二聚体，从而降低了苯三醇溶液的抗菌活性。二聚体本身的抗菌活性较低，在溶液中更稳定。与许多具有抗 X. citri 活性的其他酚类化合物不同，苯-1,2,4-三醇不是通过细胞膜渗透起作用，而是似乎限制了细胞中铁的可用性。苯-1,2,4-三醇被广泛认为是有毒的——我们的结果表明，苯-1,2,4-三醇的毒性主要归因于自发形成的二聚体。需要稳定苯-1,2,4-三醇才能允许安全使用该化合物。
