El Zawawy Nessma Ahmed, Hafez ElSayed ElSayed
Faculty of Science, Tanta University, Tanta, Egypt.
J Infect Dev Ctries. 2017 Apr 30;11(4):334-342. doi: 10.3855/jidc.8447.
This study aimed to evaluate the efficacy of Pluchea dioscoridis leaf extract on growth, survival, morphogenesis, and virulence gene expression of Candida albicans.
Anticandidal activity was studied using the hole-plate method against four pathogenic C. albicans strains from clinical isolates. The effect of the extract on the growth profile of the yeast was also examined via a time-kill assay. Microscopic observations using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were made to determine the major alterations in the microstructure of C. albicans. Quantitative changes in phospholipase, hemolysin, and secreted aspartyl proteinase (SAP1 and SAP10) genes expression as virulence factors were analyzed using real-time polymerase chain reaction (RT-PCR).
The extract exhibited high anticandidal activity, with the zones of inhibition between 0.5 and 6 cm, and recorded a minimum inhibitory concentration (MIC) value of 30 mg/mL. The time-kill study suggested that the extract possessed yeasticidal properties at higher concentrations and eradicated the growth of yeast cells. The SEM and TEM micrographs exhibited major abnormalities that occurred on the yeast cells after being exposed to the extract, resulting in complete alterations in their morphology and collapse of the cells beyond repair. At MIC concentration, phospholipase, proteinase, and hemolysin gene expression was reduced to 90%, 70%, 90% for SAP1, and 40% for SAP10, respectively, compared to that obtained from untreated C. albicans, as demonstrated by quantitative reverse transcription (RT)-PCR analysis.
The P. dioscoridis leaf extract may be an effective anticandidal agent to treat pathogenic yeast infections.
本研究旨在评估地锦草叶提取物对白色念珠菌生长、存活、形态发生和毒力基因表达的影响。
采用打孔法研究了地锦草叶提取物对4株临床分离的致病性白色念珠菌菌株的抗念珠菌活性。还通过时间杀菌试验研究了该提取物对酵母生长曲线的影响。利用扫描电子显微镜（SEM）和透射电子显微镜（TEM）进行微观观察，以确定白色念珠菌微观结构的主要变化。使用实时聚合酶链反应（RT-PCR）分析磷脂酶、溶血素和分泌天冬氨酸蛋白酶（SAP1和SAP10）基因作为毒力因子表达的定量变化。
该提取物表现出较高的抗念珠菌活性，抑菌圈在0.5至6厘米之间，最低抑菌浓度（MIC）值为30毫克/毫升。时间杀菌研究表明，该提取物在较高浓度下具有杀酵母特性，可消除酵母细胞的生长。扫描电子显微镜和透射电子显微镜照片显示，酵母细胞在接触提取物后出现了主要异常，导致其形态完全改变，细胞崩溃无法修复。定量逆转录（RT）-PCR分析表明，在MIC浓度下，与未处理的白色念珠菌相比，磷脂酶、蛋白酶和溶血素基因的表达分别降低至90%、70%、90%（SAP1）和40%（SAP10）。
地锦草叶提取物可能是治疗致病性酵母菌感染的有效抗念珠菌药物。
