Chipenzi Tafadzwa, Baloyi Genuine, Mudondo Tatenda, Sithole Simbarashe, Fru Chi Godloves, Mukanganyama Stanley
School of Pharmacy, College of Health Sciences, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe.
Department of Biochemistry, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe.
Adv Pharmacol Pharm Sci. 2020 Nov 7;2020:8848606. doi: 10.1155/2020/8848606. eCollection 2020.
ESKAPE pathogens, namely, , , , , and species, are responsible for a majority of all healthcare-acquired infections (HAI). The bacteria cause nosocomial infections in immunocompromised patients. Extracts from have been shown to have antibacterial, antifungal, and anti-inflammatory activities. Tormentic acid congener, a pentacyclic triterpene saponin, was isolated from leaves. This study aimed to investigate the antibacterial effects of tormentic acid congener and leaf extracts on biofilm formation by , , and . The antibacterial effects were determined by the microbroth dilution method, and ciprofloxacin was used as the standard antibacterial drug. Biofilm formation and detachment assays were performed using crystal violet staining. Production of extracellular polymeric DNA and polysaccharides from biofilms was also determined. Tormentic acid congener showed time-dependent antibacterial activity against with a MIC of 100 g/ml and caused significant protein leakage. Antibacterial activity was found when tormentic acid congener was tested against both and . The MICs were found to be 25 g/ml and 12.5 g/ml for and cells, respectively. was found to be susceptible to tormentic acid congener and the hydroethanolic extract with an MIC of 100 g/ml and 25 g/ml, respectively. was found not to be susceptible to the compound or the extracts. The compound and the extracts caused a significant decrease in the biofilm extracellular polysaccharide content of . The extracts and tormentic acid congener caused detachment of biofilms and decreased the release of extracellular DNA and capsular polysaccharides from biofilms of and . Tormentic acid congener and extracts, thus, have significant antibacterial and antibiofilm activities on these selected ESKAPE bacteria and can act as source lead compounds for the development of antibacterial triterpenoids.
ESKAPE病原体，即粪肠球菌（Enterococcus faecalis）、金黄色葡萄球菌（Staphylococcus aureus）、肺炎克雷伯菌（Klebsiella pneumoniae）、鲍曼不动杆菌（Acinetobacter baumannii）、绿脓杆菌（Pseudomonas aeruginosa）和肠杆菌属（Enterobacter）物种，是大多数医疗保健相关感染（HAI）的病原体。这些细菌在免疫功能低下的患者中引起医院感染。已证明委陵菜（Potentilla chinensis）提取物具有抗菌、抗真菌和抗炎活性。从委陵菜叶子中分离出了 tormentic acid同系物，一种五环三萜皂苷。本研究旨在研究tormentic acid同系物和委陵菜叶子提取物对粪肠球菌、金黄色葡萄球菌、肺炎克雷伯菌和鲍曼不动杆菌生物膜形成的抗菌作用。通过微量肉汤稀释法测定抗菌效果，环丙沙星用作标准抗菌药物。使用结晶紫染色进行生物膜形成和脱离试验。还测定了生物膜细胞外聚合DNA和多糖的产生。Tormentic acid同系物对粪肠球菌表现出时间依赖性抗菌活性，MIC为100μg/ml，并导致显著的蛋白质泄漏。当tormentic acid同系物针对金黄色葡萄球菌和肺炎克雷伯菌进行测试时，发现具有抗菌活性。发现对金黄色葡萄球菌和肺炎克雷伯菌细胞的MIC分别为25μg/ml和12.5μg/ml。发现鲍曼不动杆菌对tormentic acid同系物和乙醇提取物敏感，MIC分别为100μg/ml和25μg/ml。发现绿脓杆菌对该化合物或提取物不敏感。该化合物和提取物导致鲍曼不动杆菌生物膜细胞外多糖含量显著降低。提取物和tormentic acid同系物导致生物膜脱离，并减少了绿脓杆菌和鲍曼不动杆菌生物膜中细胞外DNA和荚膜多糖的释放。因此，tormentic acid同系物和提取物对这些选定的ESKAPE细菌具有显著的抗菌和抗生物膜活性，可作为开发抗菌三萜类化合物的先导化合物来源。
