Department of Biology, Faculty of Science, Dalhousie University, Halifax, NS B3H 4R2, Canada.
Department of Animal Science, Faculty of Animal Science and Export Agriculture, Uva Wellassa University, Badulla 90 000, Sri Lanka.
Molecules. 2019 Mar 24;24(6):1165. doi: 10.3390/molecules24061165.
There is a growing interest in medicinal plants which have been traditionally used for the treatment of human infections. This study assessed 14 ethanol extracts (EEs) on bacterial growth and biofilm formation of . Constituent major phytochemicals in the extracts were identified using ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Micro-broth dilution and time-kill assays were used to determine antibacterial activities. Anti-biofilm activities were studied using MTT assay, and morphology of biofilms was observed by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) was employed to visualize the ultra-cross section structure of bacteria treated with efficacious extracts. Licorice root, purple coneflower flower, purple coneflower stem, sage leaves and slippery elm inner bark EEs were the most effective, with minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of 62.5 μg/mL and 125 μg/mL, respectively. The minimum biofilm inhibitory concentration (MBIC) of extracts ranged from 31.5⁻250 μg/mL. Morphological changes were observed in treated biofilms compared to the untreated. The four most effective extracts exhibited the ability to induce degradation of bacterial cell wall and disintegration of the plasma membrane. We suggest that EEs of sage leaf and purple coneflower flower are promising candidates to be further investigated for developing alternative natural therapies for the management of streptococcal pharyngitis.
人们对传统上用于治疗人类感染的药用植物越来越感兴趣。本研究评估了 14 种乙醇提取物（EEs）对 的细菌生长和生物膜形成的影响。使用超高效液相色谱-电喷雾电离串联质谱（UPLC-ESI-MS/MS）鉴定提取物中的主要植物化学成分。采用微量肉汤稀释法和时间杀伤试验测定抗菌活性。使用 MTT 法研究抗生物膜活性，并通过扫描电子显微镜（SEM）观察生物膜的形态。采用透射电子显微镜（TEM）观察经有效提取物处理的细菌的超横截面结构。甘草根、紫锥花、紫锥花茎、鼠尾草叶和滑榆内皮 EE 最为有效，最小抑菌浓度（MIC）和最小杀菌浓度（MBC）分别为 62.5 μg/mL 和 125 μg/mL。提取物的最小生物膜抑制浓度（MBIC）范围为 31.5-250 μg/mL。与未处理的生物膜相比，处理过的生物膜的形态发生了变化。四种最有效的提取物具有诱导细胞壁降解和破坏质膜的能力。我们认为，鼠尾草叶和紫锥花 EE 是有前途的候选物，可进一步研究开发替代天然疗法来治疗链球菌性咽炎。
