2-Amino-nonyl-6-methoxyl-tetralin muriate inhibits sterol C-14 reductase in the ergosterol biosynthetic pathway

Abstract

Aim: To investigate the action mechanism of a novel chemical structural aminotetralin derivate, 2-Amino-Nonyl-6-Methoxyl-Tetralin Muriate (10b), against Candida albicans (C albicans) in the ergosterol biosynthetic pathway. Methods: Antifungal susceptibility test of 10b was carried out using broth microdilution method, the action mechanism of 10b against C albicans was investigated by GC-MS spectrometry and real-time RT-PCR assay, and cytotoxicity of 10b in vitro was assessed by MTS/ PMS reduction assay. Results: 10b reduced the ergosterol content markedly, and the 50% ergosterol content inhibitory concentration (ECIC 50 value) was 0.08 μg/mL. Although the sterol composition of 10b-grown cells was completely identical with that of erg24 strain, the content of ergosta-8,14,22-trienol in 10b-grown cells was much higher than that in erg24 strain. Real-time RT-PCR assay revealed a global upregulation of sterol metabolism genes. In addition, the 50% inhibitory concentration (IC 50 value) of 10b was 11.30 μg/mL for murine embryonic fibroblasts and 35.70 μg/mL for human normal liver cells. Conclusion: 10b possessed a mode of action different from that of azoles and morpholines, whose targets were sterol C-14 reductase (encoded by ERG24 gene) and sterol C-5 desaturase (encoded by ERG3) related enzyme. Although 10b seemed to reduce MTS/PMS reduction in a dose dependent manner, IC 50 value for mammalian cells was much higher than 50% minimum inhibitory concentration (MIC 50 ) value for C albicans. This indicates that the formulation is preliminarily safe and warrants further study for possible human applications.

Transcriptional response of Candida albicans biofilms following exposure to 2-amino-nonyl-6-methoxyl-tetralin muriate

“…In vitro anti-biofilm activity of 10b 10b had been reported to have great antifungal activity [36,37] , but its dramatic anti-biofilm activity was unexpected. CLSM showed that normal C albicans biofilm exhibited a typical three-dimensional structure and composed mainly of true hyphae and pseudohyphae ( Figure 2A).…”

“…10b is a novel chemical structural antifungal agent with high antifungal activity, a broad antifungal spectrum and potentially low toxicity [36,37] . In this study, we found that 10b had strong anti-biofilm activity.…”

Coumarins as new matrices for matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of hydrophobic compounds

“…DCA was chosen as an example and applied to the identification of sterols in yeast cells by MALDI-FT ICR MS. Sterols are important components of the yeast membrane and inhibiting the synthesis of or direct interaction with sterols are mechanisms of antifungal agents in clinical use [5][6][7]31]. The mechanism of resistance to azoles is also related to the metabolic pathway of sterols.…”

“…The target compounds were predominantly detected as [M + Na] + using DCA. The metabolic pathway of sterols in fungi has been reported [4,6], and based on the previous research and elemental composition analysis of target ions by high-resolution FT ICR MS, sterols and their isomers were identified by accurate mass measurements. Since FT ICR MS is high-resolution, the exact m/z values of sterols can be measured accurately to determine their elemental compositions.…”

“…For instance, sterols are the predominant components of the fungal cell membrane and inhibitors of the sterol biosynthetic pathway are potential antifungal therapeutic agents [3][4][5][6]. Metabolic profiling of fungal sterols is important for identification of antifungal drug targets and investigating mechanisms of drug resistance [7][8][9].…”