Antifungal Prenylated Diphenyl Ethers from Arthrinium arundinis, an Endophytic Fungus Isolated from the Leaves of Tobacco (Nicotiana tabacum L.).

Peng Zhang,Zhong-Feng Zhang,Yong-Mei Du,Xiao-Long Yuan,Bin-Gui Wang,Xin Li

doi:10.3390/molecules23123179

Abstract

An endophytic fungus Arthrinium arundinis TE-3 was isolated and purified from the fresh leaves of cultivated tobacco (Nicotiana tabacum L.). Chemical investigation on this fungal strain afforded three new prenylated diphenyl ethers (1–3) as well as three known analogues (4–6). Structure elucidation of the isolated compounds was carried out by analysis of 1D and 2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) spectra, as well as by comparison of those data with literature data. The absolute configuration of the stereogenic center at C-8 in 1 was assigned by comparison of the experimental and calculated ECD spectra. Compounds 1 and 2 showed selective antifungal activity against Mucor hiemalis with minimum inhibitory concentration (MIC) values of 8 and 4 μg/mL, respectively. Compounds 5 and 6 exhibited inhibitory activity against Alteraria alternata with an MIC value of 8 μg/mL. In the cytotoxic assay, 2, 5, and 6 displayed moderate in vitro cytotoxicity against the human monocytic cell line (THP-1 cell line), with IC50 values of 40.2, 28.3, and 25.9 μM, respectively. This study indicated that endophytic fungi possess great potential for exploring new bioactive secondary metabolites.

Highlights

Endophytic microorganisms are those that inhabit at the internal living tissues of plants without causing visible damage to their hosts [1]
Chemical and biological investigations on this fungal strain have led to the isolation and identification of three new prenylated diphenyl ethers (1–3) and previously described compounds (4–6) (Figure 1)
Its molecular formula −was determined to be as evidenced from the quasimolecular ion peak at m/z 381.2076 [M − H]

Summary

Introduction

Endophytic microorganisms are those that inhabit at the internal living tissues of plants without causing visible damage to their hosts [1]. Endophytes have attracted great attention due to their potential to produce extensive bioactive secondary metabolites with prominent medicinal and/or agricultural applications [3,4,5]. During our continuous research to discover structurally novel secondary metabolites from endophytic fungi, especially in the searching for those with promising cytotoxic and antifungal activities [6,7,8], we isolated and purified an endophytic fungus Arthrinium arundinis TE-3 from the fresh leaves of cultivated tobacco (Nicotiana tabacum L.). Chemical and biological investigations on this fungal strain have led to the isolation and identification of three new prenylated diphenyl ethers (1–3) and previously described compounds (4–6) (Figure 1) These compounds incorporate one or more prenyl groups, and some of which were modified as isopentenyl, dihydrofuran, and dihydropyran moieties [9,10]

Methods

Results

Conclusion