College of Animal Science and Technology, Northwest A&F University, Yangling, China.
J Fish Dis. 2022 Nov;45(11):1599-1607. doi: 10.1111/jfd.13683. Epub 2022 Jul 8.
Nocardiosis caused by Nocardia seriolae is a major threat to the aquaculture industry. Given that prolonged therapy administration can lead to a growth of antibiotic resistant strains, new antibacterial agents and alternative strategies are urgently needed. In this study, 80 medicinal plants were selected for antibacterial screening to obtain potent bioactive compounds against N. seriolae infection. The methanolic extracts of Magnolia officinalis exhibited the strongest antibacterial activity against N. seriolae with the minimal inhibitory concentration (MIC) of 12.5 μg/ml. Honokiol and magnolol as the main bioactive components of M. officinalis showed higher activity with the MIC value of 3.12 and 6.25 μg/ml, respectively. Sequentially, the evaluation of antibacterial activity of honokiol in vivo showed that honokiol had good biosafety, and could significantly reduce the bacterial load of nocardia-infected largemouth bass (p < .001). Furthermore, the survival rate of nocardia-infected fish fed with 100 mg/kg honokiol was obviously improved (p < .05). Collectively, these results suggest that medicinal plants represent a promising reservoir for discovering active components against Nocardia, and honokiol has great potential to be developed as therapeutic agents to control nocardiosis in aquaculture.
海洋分枝杆菌引起的诺卡氏菌病是水产养殖业的主要威胁。由于长期使用抗生素治疗可能会导致抗药性菌株的生长，因此迫切需要新的抗菌剂和替代策略。在这项研究中，选择了 80 种药用植物进行抗菌筛选，以获得针对海洋分枝杆菌感染的有效生物活性化合物。厚朴的甲醇提取物对海洋分枝杆菌的抗菌活性最强，最小抑菌浓度（MIC）为 12.5μg/ml。厚朴酚和木兰醇是厚朴的主要生物活性成分，其 MIC 值分别为 3.12μg/ml 和 6.25μg/ml，活性更高。随后，对 honokiol 在体内的抗菌活性进行评估，结果表明 honokiol 具有良好的生物安全性，可显著降低感染海洋分枝杆菌的大口黑鲈的细菌载量（p<0.001）。此外，投喂 100mg/kg honokiol 的感染海洋分枝杆菌的鱼的存活率明显提高（p<0.05）。综上所述，这些结果表明，药用植物是发现针对诺卡氏菌的活性成分的有前途的来源，厚朴酚具有作为治疗剂控制水产养殖中诺卡氏菌病的巨大潜力。
