Infectomics Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Bertam 13200 Kepala Batas, Penang, Malaysia.
Faculty of Language and Communication, Universiti Pendidikan Sultan Idris, Perak, Malaysia.
Mycopathologia. 2021 May;186(2):221-236. doi: 10.1007/s11046-020-00523-z. Epub 2021 Feb 7.
Candida albicans has been reported globally as the most widespread pathogenic species contributing candidiasis from superficial to systemic infections in immunocompromised individuals. Their metabolic adaptation depends on glyoxylate cycle to survive in nutrient-limited host. The long term usage of fungistatic drugs and the lack of cidal drugs frequently result in strains that could resist commonly used antifungals and display multidrug resistance (MDR). In search of potential therapeutic intervention and novel fungicidals, we have explored a plant alkaloids, namely arborinine and graveoline for its antifungal potential. Alkaloids belongs to Rutaceae family have been reported with numerous antimicrobial activities. In this study, we aimed to isolate and identify the antifungal active alkaloids of R. angustifolia and assess antifungal effect targeting C. albicans isocitrate lyase (ICL) gene which regulates isocitrate lyase, key enzyme in glyoxylate cycle contributing to the virulence potential of C. albicans. Alkaloids were extracted by bioassay guided isolation technique which further identified by TLC profile and compared with the standard through HPLC and NMR analysis. The antifungal activities of the extracted alkaloids were quantified by means of MIC (Minimum Inhibitory Concentration). The gene expression of the targeted gene upon treatment was analysed using RT-qPCR and western blot. Additionally, this study looked at the drug-likeness and potential toxicity effect of the active alkaloid compounds in silico analysis. Spectroscopic analysis showed that the isolated active alkaloids were characterized as acridone, furoquinoline, 4-quinolone known as arborinine and graveoline. Results showed that each compound significantly inhibited the growth of C. albicans at the dose of 250 to 500 µg/mL which confirm its antifungal activity. Each alkaloid was found to successfully downregulate the expression of both ICL1 gene CaIcl1 protein. Finally, ADMET analysis suggests a good prediction of chemical properties, namely absorption, distribution, metabolism, excretion and toxicity (ADMET) that will contribute in drug discovery and development later on.
白色念珠菌已在全球范围内被报道为最广泛分布的致病性物种，可导致免疫功能低下个体的浅部至深部感染。其代谢适应依赖于乙醛酸循环以在营养有限的宿主中存活。长期使用抑菌药物和缺乏杀菌药物常常导致能够抵抗常用抗真菌药物并表现出多药耐药性（MDR）的菌株。为了寻找潜在的治疗干预和新型杀真菌剂，我们研究了植物生物碱，即阿比诺林和格拉沃林，以评估其抗真菌潜力。生物碱属于芸香科，具有多种抗菌活性。在这项研究中，我们旨在分离和鉴定 R. angustifolia 的抗真菌活性生物碱，并评估其针对靶向 C. albicans 异柠檬酸裂解酶（ICL）基因的抗真菌效果，该基因调节异柠檬酸裂解酶，是乙醛酸循环中的关键酶，有助于 C. albicans 的毒力潜力。生物碱通过生物测定指导分离技术提取，然后通过 TLC 图谱进一步鉴定，并通过 HPLC 和 NMR 分析与标准品进行比较。通过最低抑菌浓度（MIC）定量测定提取生物碱的抗真菌活性。使用 RT-qPCR 和 Western blot 分析处理后靶基因的表达。此外，这项研究还通过计算机分析研究了活性生物碱化合物的药物相似性和潜在毒性作用。光谱分析表明，分离出的活性生物碱被鉴定为吖啶酮、呋喃喹啉、4-喹啉，分别为阿比诺林和格拉沃林。结果表明，每种化合物在 250 至 500µg/mL 的剂量下均显著抑制 C. albicans 的生长，证实了其抗真菌活性。发现每种生物碱都能成功地下调 ICL1 基因 CaIcl1 蛋白的表达。最后，ADMET 分析表明对化学性质（即吸收、分布、代谢、排泄和毒性（ADMET））有良好的预测，这将有助于以后的药物发现和开发。
