中文摘要：

目的研究土槿乙酸B（PLAB）的体外抗真菌活性和对白色念珠菌细胞膜中麦角甾醇生物合成的影响.方法：采用微量液体稀释法研究PLAB 的体外抗白色念珠菌、新生隐球菌、絮状表皮癣菌的活性.将白色念珠菌经不同浓度PLAB 及氟康唑作用28 h 后,经过皂化、提取未皂化脂,采用高效液相色谱法测定其麦角甾醇的含量变化.结果：PLAB 对白色念珠菌、新生隐球菌、絮状表皮癣菌这三株菌株的MIC50分别为16、32、16 μg·mL-1.PLAB能使白色念珠菌中的麦角甾醇含量下降（P 〈0.05）,且含量变化呈明显的剂量依赖性.结论：PLAB 具有较强的抗真菌作用,通过抑制真菌的麦角甾醇生物合成而发挥高效抗真菌活性.

英文摘要：

Objective： To study antifungal activity in vitro and the effect of pseudolaric acid B （PLAB） on ergosterolbiosynthesis in the cell membranes of Candida albicans. Methods： Microdilution method was used to determine the susceptibilityof fungus （Candida albicans, Cryptococcus neoformans, Epidermophyton floccosum） to PLAB. The Candida albicans wereincubated for 28 h with different concentrations of PLAB and fluconazole, and the content of ergosterol was detected by HPLC aftersaponification and extraction. Results： The MIC50 （minimum inhibition concentrations） of PLAB to Candida albicans, Cryptococcusneoformans, Epidermophyton floccosum was 16, 32, 16 μg·mL-1 respectively. PLAB could decrease the content of ergosterol （P 〈0.05） in Candida albicans with a dose-dependent manner. Conclusion： PLAB had remarkable antifungal activity by inhibiting theergosterol biosynthesis in fungi.