Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa.
J Ethnopharmacol. 2012 Jun 14;141(3):1041-50. doi: 10.1016/j.jep.2012.03.051. Epub 2012 Apr 6.
There is an increase in antimicrobial resistance and complexities arising from verotoxic related bacterial infections as well as rise in demand for application of natural antioxidants to combat oxidative damage by free radicals in many oxidative stress-mediated disease conditions such as cancer. Thus the potential of Curtisia dentata as antimicrobial, antioxidant and antiverotoxin against environmental isolates of Escherichia coli and Acinetobacter spp. as well as the presence of phytochemicals and some organic compounds, was determined.
Phytochemical analysis was carried out using standard methods and antioxidant activity was determined using the DPPH radical scavenging activity. Effect of extracts on bacterial cell wall was also determined.
Extracts contained anthraquinones, alkaloids, essential oils, glycosides, phenols, steroids, saponins, tannins, quinones, anthocyanins, amines and carboxylic acids as phytochemicals. Extracts demonstrated high antimicrobial activity and low minimum inhibitory concentrations as well as inhibitory action against the expression of both Vtx1 and Vtx2 genes in Escherichia coli, Acinetobacter haemolyticus and Acinetobacter lwoffii. Ethanol root bark extracts consistently showed the highest DPPH radical scavenging activity (62.43%), total phenol content (TPH) (57.62 26 mg GAE/g) and reducing power (RP) (41.32%), followed by those of the stem bark and leaf extracts with the respective values of 54.68%, 37.77 mg GAE/g and 21.83%. The extracts induced the leakage of Na(+) and K(+) ions from both test bacteria.
Curtisia dentata is a very effective source of antioxidant and a possible alternative to sourcing antiverotoxic antibiotics with novel mechanism of action.
由于与 verotoxin 相关的细菌感染导致抗微生物药物耐药性和复杂性增加，以及在许多氧化应激介导的疾病情况下，如癌症，需要应用天然抗氧化剂来对抗自由基引起的氧化损伤，因此，Curtisia dentata 作为抗微生物、抗氧化剂和抗 verotoxin 的潜力针对环境分离的大肠杆菌和不动杆菌以及植物化学物质和一些有机化合物的存在进行了评估。
使用标准方法进行植物化学分析，并使用 DPPH 自由基清除活性测定抗氧化活性。还测定了提取物对细菌细胞壁的影响。
提取物含有蒽醌、生物碱、精油、糖苷、酚类、类固醇、皂苷、单宁、醌类、花青素、胺类和羧酸类作为植物化学物质。提取物表现出高抗菌活性和低最小抑菌浓度，以及对大肠杆菌、溶血不动杆菌和洛菲不动杆菌中 Vtx1 和 Vtx2 基因表达的抑制作用。乙醇根皮提取物始终表现出最高的 DPPH 自由基清除活性（62.43%）、总酚含量（TPH）（57.62 26 mg GAE/g）和还原能力（RP）（41.32%），其次是茎皮和叶提取物，分别为 54.68%、37.77 mg GAE/g 和 21.83%。提取物从测试细菌中诱导了 Na(+)和 K(+)离子的泄漏。
Curtisia dentata 是一种非常有效的抗氧化剂来源，可能是寻找具有新型作用机制的抗 verotoxin 抗生素的替代来源。
