Faculty of Science and Agriculture, Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag X1106, Sovenga 0727, South Africa.
Lett Appl Microbiol. 2024 Sep 2;77(9). doi: 10.1093/lambio/ovae080.
Biofilms are responsible for over 60% of nosocomial infections. The focus of this study was to investigate the antioxidant, antibacterial, antibiofilm, and anti-motility activities of Gardenia volkensii, Carissa bispinosa, Peltophorum africanum, and Senna petersiana. Antioxidant activity was evaluated using free radical (DPPH) scavenging and ferric reducing power assays. Antibacterial and antibiofilm activities were evaluated using the broth micro-dilution and the crystal violet assays, respectively. Anti-motility was evaluated using anti-swarming activities, and the brine shrimp lethality assay was used for cytotoxicity. Gardenia volkensii and C. bispinosa acetone extracts had low EC50 values of 9.59 and 9.99 μg ml-1on the free-radical scavenging activity, respectively. All the plant extracts demonstrated broad-spectrum antibacterial activity against Klebsiella pneumoniae, Pseudomonasa aeruginosa, Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus [minimum inhibitory concentration (MIC) < 0.63 mg ml-1]. The initial cell adherence stage of P. aeruginosa and E. coli was the most susceptible stage where sub-MICs resulted in inhibitions >50%. Peltophorum africanum had the least cytotoxic effects. All extracts had anti-motility activity against P. aeruginosa and E. coli. This study showed that not only do the plants have strong antibacterial activity but had noteworthy inhibition (>50%) of initial cell adherence and may be suitable candidates for the treatment of nosocomial pathogens.
生物膜导致了超过 60%的医院获得性感染。本研究的重点是研究栀子、山芝麻、非洲朴和腊肠树的抗氧化、抗菌、抗生物膜和抗运动活性。抗氧化活性通过自由基（DPPH）清除和铁还原能力测定来评估。抗菌和抗生物膜活性分别通过肉汤微量稀释法和结晶紫测定来评估。运动性通过抗群集活性来评估，并且使用盐水虾致死试验来评估细胞毒性。栀子和山芝麻丙酮提取物在自由基清除活性上的 EC50 值分别为 9.59 和 9.99 μg ml-1。所有植物提取物均表现出针对肺炎克雷伯菌、铜绿假单胞菌、大肠杆菌、粪肠球菌和金黄色葡萄球菌的广谱抗菌活性（最小抑菌浓度（MIC）< 0.63 mg ml-1）。铜绿假单胞菌和大肠杆菌的初始细胞黏附阶段是最易受影响的阶段，亚 MIC 浓度导致抑制率> 50%。非洲朴的细胞毒性最小。所有提取物均对铜绿假单胞菌和大肠杆菌具有抗运动活性。本研究表明，这些植物不仅具有强大的抗菌活性，而且对初始细胞黏附具有显著的抑制作用（> 50%），可能是治疗医院病原体的合适候选药物。
