Candida albicans is a major fungal pathogen in humans. In our previous study, we reported that an ethanol extract from Aucklandia lappa weakens C. albicans cell wall by inhibiting synthesis or assembly of both (1,3)-β-D-glucan polymers and chitin. In the current study, we found that the extract is involved in permeabilization of C. albicans cell membranes. While uptake of ethidium bromide (EtBr) was 3.0% in control cells, it increased to 7.4% for 30 min in the presence of the A. lappa ethanol extract at its minimal inhibitory concentration (MIC), 0.78 mg/mL, compared to uptake by heat-killed cells. Besides, leakage of DNA and proteins was observed in A. lappa-treated C. albicans cells. The increased uptake of EtBr and leakage of cellular materials suggest that A. lappa ethanol extract induced functional changes in C. albicans cell membranes. Incorporation of diphenylhexatriene (DPH) into membranes in the A. lappa-treated C. albicans cells at its MIC decreased to 84.8%, after 60 min of incubation, compared with that of the controls, indicate that there was a change in membrane dynamics. Moreover, the anticandidal effect of the A. lappa ethanol extract was enhanced at a growth temperature of 40°C compared to that at 35°C. The above data suggest that the antifungal activity of the A. lappa ethanol extract against C. albicans is associated with synergistic action of membrane permeabilization due to changes in membrane dynamics and cell wall damage caused by reduced formation of (1,3)-β-D-glucan and chitin.

中文翻译：

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Aucklandia lappa 引起白色念珠菌的膜渗透。

白色念珠菌是人类的主要真菌病原体。在我们之前的研究中，我们报道了来自Aucklandia lappa的乙醇提取物通过抑制 (1,3)-β-D-葡聚糖聚合物和几丁质的合成或组装来削弱白色念珠菌细胞壁。在当前的研究中，我们发现该提取物参与了白色念珠菌细胞膜的透化作用。虽然溴化乙锭 (EtBr) 在对照细胞中的摄取率为 3.0%，但在A.lappa乙醇提取物存在的情况下，它增加到 7.4%，持续 30 分钟，其最小抑制浓度 (MIC) 为 0.78 mg/mL，与摄取相比通过热灭活细胞。此外，在A. lappa处理的白色念珠菌中观察到 DNA 和蛋白质的泄漏细胞。EtBr 摄取的增加和细胞材料的渗漏表明，A.lappa乙醇提取物诱导了白色念珠菌细胞膜的功能变化。在孵育 60 分钟后，与对照相比，在A.lappa处理的白色念珠菌细胞中，二苯基己三烯 (DPH)在其 MIC 处的细胞膜中的掺入率下降至 84.8%，表明膜动力学发生了变化。此外，与35°C 相比，在 40°C 的生长温度下A.lappa乙醇提取物的抗念珠菌作用得到增强。上述数据表明A.lappa乙醇提取物对白色念珠菌的抗真菌活性由于 (1,3)-β-D-葡聚糖和几丁质形成减少引起的膜动力学变化和细胞壁损伤，与膜透化的协同作用有关。