PDF(Pubmed)
Abstract：
Candidiasis is considered an emerging public health concern because of the occurrence of drug-resistant Candida strains and the lack of an available structurally diverse antifungal drug armamentarium. The indole alkaloid globospiramine from the anticandidal Philippine medicinal plant Voacanga globosa exhibits a variety of biological activities; however, its antifungal properties remain to be explored. In this study, we report the in vitro anticandidal activities of globospiramine against two clinically relevant Candida species (C. albicans and C. tropicalis) and the exploration of its possible target proteins using in silico methods. Thus, the colony-forming unit (CFU) viability assay revealed time- and concentration-dependent anticandidal effects of the alkaloid along with a decrease in the number of viable CFUs by almost 50% at 60 min after treatment. The results of the MIC and MFC assays indicated inhibitory and fungicidal effects of globospiramine against C. albicans (MIC = 8 µg/mL; MFC = 8 µg/mL) and potential fungistatic effects against C. tropicalis at lower concentrations (MIC = 4 µg/mL; MFC > 64 µg/mL). The FAM-FLICA poly-caspase assay showed metacaspase activation in C. albicans cells at concentrations of 16 and 8 µg/mL, which agreed well with the MIC and MFC values. Molecular docking and molecular dynamics simulation experiments suggested globospiramine to bind strongly with 1,3-β-glucan synthase and Als3 adhesin-enzymes indirectly involved in apoptosis-driven candidal inhibition.
摘要：
念珠菌病被认为是一种新兴的公共卫生问题，因为耐药念珠菌菌株的出现以及缺乏可用的结构多样化的抗真菌药物。来自菲律宾抗虫药植物Voacangaglobosa的吲哚生物碱球形螺旋胺表现出多种生物活性；但是，其抗真菌特性仍有待探索。在这项研究中,我们报道了球形螺旋胺对两种临床相关的念珠菌的体外抗虫活性（C.白色念珠菌和热带念珠菌），并使用计算机模拟方法探索其可能的靶蛋白。因此，菌落形成单位（CFU）活力测定显示，生物碱具有时间和浓度依赖性的抗虫作用，并且在治疗后60分钟，活CFU的数量减少了近50％。MIC和MFC测定的结果表明，球形螺旋胺对白色念珠菌的抑制和杀真菌作用（MIC=8µg/mL；MFC=8µg/mL），以及在较低浓度下对热带念珠菌的潜在真菌抑制作用（MIC=4µg/mL；MFC>64µg/mL）。FAM-FLICApoly-caspase分析显示，在浓度为16和8µg/mL的白色念珠菌细胞中，这与MIC和MFC值非常吻合。分子对接和分子动力学模拟实验表明，球形螺旋胺与1,3-β-葡聚糖合酶和Als3粘附素酶强烈结合，间接参与凋亡驱动的念珠菌抑制。
