中文摘要：

目的：测定土槿乙酸（pseudolaric acidB，PLAB）对白色念珠菌（caudida albicans）标准菌株Cla的最低抑菌浓度（MIC），并在透射电镜下观察经PLAB作用后，白色念珠菌超微结构的改变，探讨其作用机制，从而为抗白色念珠菌的中药开发提供理论依据。方法：用液体稀释法检测PLAB对白色念珠菌Cla的MIC，透射电镜下观察经不同浓度PLAB作用前后白色念珠菌Cla超微结构的改变，两性霉素B（AmB）为阳性对照药物。结果：PLAB对白色念珠菌Cla的MIC为32μg／ml。透射电镜观察发现，AmB处理组白色念珠菌Cla形态基本正常，但细胞壁结构疏松，有裂口，细胞膜缺失较严重，胞浆内容物漏出。经PLAB处理组白色念珠菌Cla细胞变形，结构模糊，细胞壁疏松，有裂口，细胞膜连续性破坏，进而破碎成碎片互相融合，细胞器肿胀乃至坏死溶解，甚至胞浆内容物全部漏出呈“空壳”状。结论：PLAB有抗白色念珠菌作用，可能通讨破坏白色念珠菌的细胞肇、细胞膜、细胞核的结构而汰到杭真菌作用。

英文摘要：

OBJECTIVE To determine the susceptibility of identified quality control （ QC ） strains （ Candida albicans ） to PLAB and to explore the antifungal mechanism of PLAB, so as to provide evidence for the development of antifungal medicinal herbs. METHODS The minimum inhibitory concentrations （ MIC ） of PLAB was determined by broth dilution method. Positive control drug was AmB. Ultra - structural changes of C. albicans were observed by electron microscopy before and after PLAB and AmB treatment. RESULTS The previously identified quality control （ QC ） strains （ Candida albicans ） were susceptible to PLAB, It＇ s MIC was 32 μg/ml. From the photograph observed by TEM, it was seen that after treated with AmB, the fungal morphology and ultrastructure were normal on the whole, but their cell wall and membrane especially cell membrane were depletion. After treatment with PLAB, the morphology and ultrastructure of Candida albicans showed obvious changes ： their cell wall and cytoplasmic membrane ruptured; and the cell residues fused into irregular masses; intracellular components leak out, organelle swell, dissolve and formed large blank region. There were no changes in the morphology and ultrastructure of Candida albicans treated with 0 μg/ml PLAB.. CONCLUSION The data indicates that PLAB has antlfungal effect on C. albican and thus has great clinical importance. The antifungal mechanism of PLAB may be that the structure of cell wall and cell membrane of C. albicans are inhibited.