Panda Sujogya Kumar, Reynders Michelle, Kipanga Purity N, Luyten Walter
Department of Biology, Katholieke Universiteit (KU) Leuven, Leuven, Belgium.
Centre for Biotechnology, Siksha 'O' Anusandhan (Deemed to be University), Bhubaneswar, India.
Front Cell Infect Microbiol. 2025 Jan 17;14:1494589. doi: 10.3389/fcimb.2024.1494589. eCollection 2024.
is used frequently in African traditional medicine for treating infectious diseases. Previous bioassay-guided purification has identified hydroquinone as the major bio-active compound in the aforementioned plant, responsible for its antibacterial activity against . While the phenol hydroquinone can be directly extracted from the plant, it may undergo (reversible) oxidation under mild conditions to yield benzoquinone, a compound with known antimicrobial activity against .
We, examined whether hydroquinone or its oxidation product, benzoquinone, is the active compound against bacteria such as . To achieve this we performed broth microdilution (planktonic) and biofilm activity tests against two different strains of . The inhibitory concentrations (IC) of benzoquinone and hydroquinone under various circumstances were compared, assessing their stability, and examining their effectiveness against two strains of (Rosenbach and USA 300) in both planktonic and biofilm environments.
Benzoquinone demonstrated antibacterial activity against Rosenbach and USA 300 with IC of 6.90 ± 2.30 mM and 7.72 ± 2.73 mM, respectively, while the corresponding values for hydroquinone were 15.63 ± 2.62 mM and 19.21 ± 4.84 mM, respectively. However, when oxidation was prevented by the addition of antioxidants such as ascorbic acid or glutathione, hydroquinone lost its antibacterial property, while benzoquinone retained activity. Comparing conditions in which hydroquinone could convert into benzoquinone against conditions in which this conversion was inhibited, showed that hydroquinone alone did not inhibit bacterial growth of , while benzoquinone alone did.
These results prove that the oxidation product benzoquinone is responsible for the antimicrobial activity previously ascribed to hydroquinone.
在非洲传统医学中常用于治疗传染病。先前的生物测定引导纯化已确定对苯二酚是上述植物中的主要生物活性化合物，负责其对[具体细菌名称未给出]的抗菌活性。虽然苯酚对苯二酚可直接从植物中提取，但它可能在温和条件下发生（可逆）氧化生成苯醌，苯醌是一种对[具体细菌名称未给出]具有已知抗菌活性的化合物。
我们研究了对苯二酚或其氧化产物苯醌是否是针对诸如[具体细菌名称未给出]等细菌的活性化合物。为实现这一目标，我们针对两种不同的[具体细菌名称未给出]菌株进行了肉汤微量稀释（浮游菌）和生物膜活性测试。比较了苯醌和对苯二酚在各种情况下的抑制浓度（IC），评估了它们的稳定性，并研究了它们在浮游菌和生物膜环境中对两种[具体细菌名称未给出]菌株（罗森巴赫菌和美国300株）的有效性。
苯醌对罗森巴赫菌和美国300株的抗菌活性的IC分别为6.90±2.30 mM和7.72±2.73 mM，而对苯二酚的相应值分别为15.63±2.62 mM和19.21±4.84 mM。然而，当通过添加抗坏血酸或谷胱甘肽等抗氧化剂防止氧化时，对苯二酚失去其抗菌性能，而苯醌保留活性。将对苯二酚可转化为苯醌的条件与该转化被抑制的条件进行比较，结果表明单独的对苯二酚不抑制[具体细菌名称未给出]的细菌生长，而单独的苯醌则可以。
这些结果证明氧化产物苯醌是先前归因于对苯二酚的抗菌活性的原因。
