Department of Biochemistry and Microbiology, UCT Prague, Faculty of Food and Biochemical Technology, Prague, Czech Republic.
Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.
J Ethnopharmacol. 2023 Aug 10;312:116484. doi: 10.1016/j.jep.2023.116484. Epub 2023 Apr 10.
Salvia officinalis L., Sambucus nigra L., Matricaria chamomilla L., Agrimonia eupatoria L., Fragaria vesca L. and Malva sylvestris L. are plants that have a long tradition in European folk medicine. To this day, they are part of medicinal teas or creams that help with the healing of skin wounds and the treatment of respiratory or intestinal infections. However, so far these plants have not been investigated more deeply than in their direct antibacterial effect.
Our research is focused on adjuvants that inhibit the mechanism of antibiotic resistance or modulate bacterial virulence. Based on a preliminary screening of 52 European herbs, which commonly appear as part of tea blends or poultice. Six of them were selected for their ability to revert the resistant phenotype of nosocomial bacterial strains.
Herbs selected for this study were obtained from commercially available sources. For the extraction of active compounds ethanol was used. Modulation of virulence was observed as an ability to inhibit bacterial cell-to-cell communication using two mutant sensor strains of Vibrio campbellii. Biofilm formation, and planktonic cell adhesion was measured using a static antibiofilm test. Ethidium bromide assay was used to checked the potential of inhibition bacterial efflux pumps. The antibacterial activities of the herbs were evaluated against resistant bacterial strains using macro dilution methods.
Alcohol extracts had antibacterial properties mainly against Gram-positive bacteria. Of all of them, the highest antimicrobial activity demonstrated Malva sylvestris, killing both antibiotic resistant bacteria; Staphylococcus aureus with MIC of 0.8 g/L and Pseudomonas aeruginosa 0.7 g/L, respectively. Fragaria vesca extract (0.08 g/L) demonstrated strong synergism with colistin (4 mg/L) in modulating the resistant phenotype to colistin of Pseudomonas aeruginosa. Similarly, the extract of S. officinalis (0.21 g/L) reverted resistance to gentamicin (1 mg/L) in S. aureus. However, Sambucus nigra and Matricaria chamomilla seem to be a very promising source of bacterial efflux pump inhibitors.
The extract of F. vesca was the most active. It was able to reduce biofilm formation probably due to the ability to decrease bacterial quorum sensing. On the other hand, the activity of S. nigra or M. chamomilla in reducing bacterial virulence may be explained by the ability to inhibit bacterial efflux systems. All these plants have potential as an adjuvant for the antibiotic treatment.
鼠尾草、黑接骨木、甘菊、龙芽草、野草莓和锦葵是欧洲民间医学中具有悠久传统的植物。时至今日，它们仍是药用茶或乳膏的一部分，有助于治疗皮肤伤口和呼吸道或肠道感染。然而，到目前为止，这些植物的研究还没有深入到它们的直接抗菌作用之外。
我们的研究重点是抑制抗生素耐药机制或调节细菌毒力的佐剂。基于对常见于茶混合或膏药中的 52 种欧洲草药的初步筛选，选择了其中 6 种具有使医院细菌菌株恢复耐药表型的能力。
本研究中选择的草药从市售来源获得。使用乙醇提取活性化合物。使用两种霍乱弧菌突变传感器菌株观察到细菌细胞间通讯的抑制作为毒力调节。使用静态抗生物膜测试测量生物膜形成和浮游细胞粘附。使用溴化乙锭测定法检查抑制细菌外排泵的潜力。使用宏稀释方法评估草药对耐药细菌菌株的抗菌活性。
酒精提取物主要对革兰氏阳性菌具有抗菌作用。在所有提取物中，锦葵的抗菌活性最高，分别杀死了两种抗生素耐药菌：金黄色葡萄球菌（MIC 为 0.8 g/L）和铜绿假单胞菌（MIC 为 0.7 g/L）。野草莓提取物（0.08 g/L）与多粘菌素（4 mg/L）在调节铜绿假单胞菌对多粘菌素的耐药表型方面表现出很强的协同作用。同样，圣约翰草（0.21 g/L）提取物可使金黄色葡萄球菌对庆大霉素（1 mg/L）的耐药性逆转。然而，黑接骨木和甘菊似乎是细菌外排泵抑制剂的非常有前途的来源。
野草莓提取物最为活跃。它能够减少生物膜形成，可能是因为它能够降低细菌群体感应。另一方面，黑接骨木或甘菊降低细菌毒力的活性可能是由于抑制细菌外排系统的能力。所有这些植物都有可能作为抗生素治疗的佐剂。
