New Dihydroisocoumarin Root Growth Inhibitors From the Sponge-Derived Fungus Aspergillus sp. NBUF87.

Liming Huang,Shan He,J Enrico H Lazaro,Lijian Ding,Xiao Wang,Ning Wang,Xiaojun Yan,Xiaohui Li,C Benjamin Naman,Wei Cui

doi:10.3389/fmicb.2019.02846

Abstract

Six new dihydroisocoumarins, aspergimarins A−F (1−6), were discovered together with five known analogs (7−11) from a monoculture of the sponge-derived fungus Aspergillus sp. NBUF87. The structures of these compounds were elucidated through comprehensive spectroscopic methods, and absolute configurations were assigned after X-ray crystallography, use of the modified Mosher’s method, and comparison of electronic circular dichroism (ECD) data with literature values for previously reported analogs. Compounds 1−11 were evaluated in a variety of bioassays, and at 100 μM, both 1 and 5 showed significant inhibitory effects on the lateral root growth of Arabidopsis thaliana Columbia-0 (Col-0). Moreover, at 100 μM, 5 also possessed notable inhibition against the primary root growth of Col-0. Meanwhile, 1−11 were all found to be inactive in vitro against acetylcholinesterase (AChE) (IC50 > 100 μM), four different types of human-derived cancer cell lines (IC50 > 50 μM), as well as methicillin-resistant Staphylococcus aureus and Escherichia coli (MIC > 50 μg/mL), and Plasmodium falciparum W2 (EC50 > 100 μg/mL), in phenotypic tests.

Highlights

Sponges are among the most primitive multicellular invertebrates and harbor vast microbial populations, owing largely to the unique filter-feeding physiology that is full of pores and channels (Hentschel et al, 2006; Webster and Taylor, 2012)
Electronic circular dichroism (ECD) spectra were collected on a JASCO J-1500 spectrophotometer. 1D and 2D NMR spectra were recorded in DMSO-d6 with a Palo Alto Varian 600 MHz spectrometer, using standard pulse sequences
The NMR data suggested the presence of a dihydroisocoumarin skeleton contained in 1

Summary

Introduction

Sponges are among the most primitive multicellular invertebrates and harbor vast microbial populations, owing largely to the unique filter-feeding physiology that is full of pores and channels (Hentschel et al, 2006; Webster and Taylor, 2012). The secondary metabolites from sponge-derived Aspergillus fungi have been reported from many classes, including polyketides (Wang et al, 2014; Kong et al, 2015), terpenoids (Liu et al, 2009; Li D. et al, 2012), alkaloids (Zhou et al, 2013, 2014), diketopiperazines (Ahmed et al, 2017), and peptides (Lee et al, 2011). Many of these metabolites have been shown to exhibit strong antitumor, antibacterial, antiviral, and other bioactivities

Methods

Results

Conclusion