Department of Plant Biology, Course of Pharmacy and BTPB Program, Institute of Biology, State University of Campinas 13083-970, Cx Postal 6109, Campinas, SP, Brazil.
Curr Drug Targets. 2013 Aug;14(9):1015-22. doi: 10.2174/1389450111314090010.
This study was undertaken to evaluate the effect of Alternathera brasiliana (Amaranthaceae) extracts as photosensitizing agents in photodynamic antimicrobial therapies (PACT) against Staphylococcus aureus, Staphylococcus epidermidis and Candida dubliniensis. The crude hexane and ethanol extracts were obtained from A. brasiliana whole plant and showed absortion from 650 to 700 nm. Also, singlet molecular oxygen (1O2) production (type II photosensitization reaction) was examined, and the results show that 1,3-diphenylisobenzofuran photodegradation was greatly enhanced in the presence of the A. brasiliana extracts. One plate in each assay was irradiated while the other was not irradiated, the number of colony-forming units per milliliter (CFU/mL) was obtained, and data analyzed by the Tukey test. The chemical composition of the extracts was determined by chromatographic and spectrometric techniques; steroids, triterpenes, and flavonoids were identified. Laser irradiation alone at 685 nm using diode laser, output power of 35 mW, and energy of 28 J/cm2, or non-irradiated crude extracts in sub-inhibitory concentration did not reduce the number of CFU/mL significantly, whereas irradiated hexane and ethanol extracts, in sub-inhibitory concentrations, inhibited the growth of these microorganisms. The photoactivation of hexane and ethanol extracts of A. brasiliana, in sub-inhibitory concentrations, using red laser radiation at 685 nm had an antimicrobial effect.
本研究旨在评估 Alternathera brasiliana（苋科）提取物作为光敏剂在光动力抗菌治疗（PACT）中的作用，以对抗金黄色葡萄球菌、表皮葡萄球菌和杜宾氏念珠菌。从 A. brasiliana 全草中提取得到粗的正己烷和乙醇提取物，其吸收光谱在 650 至 700nm 之间。此外，还检查了单线态氧（1O2）的产生（II 型光致氧化反应），结果表明，在 A. brasiliana 提取物存在的情况下，1,3-二苯基异苯并呋喃的光降解得到了极大的增强。每个试验板的一个板进行照射，而另一个板不进行照射，获得每毫升（CFU/mL）的菌落形成单位数（CFU/mL），并通过 Tukey 检验进行数据分析。通过色谱和光谱技术确定提取物的化学成分；鉴定出甾体、三萜和黄酮类化合物。单独使用 685nm 的二极管激光照射，输出功率为 35mW，能量为 28J/cm2，或在亚抑菌浓度下未照射的粗提取物，不会显著减少 CFU/mL 的数量，而在亚抑菌浓度下照射的正己烷和乙醇提取物则抑制了这些微生物的生长。在亚抑菌浓度下，使用 685nm 红光对 A. brasiliana 的正己烷和乙醇提取物进行光激活，具有抗菌作用。
