Phenylhydrazone and Quinazoline Derivatives from the Cold-Seep-Derived Fungus Penicillium oxalicum

Ya-Ping Liu,Zhen-Zhen Shi,Nai-Yun Ji,Sheng-Tao Fang,Xiao-Nian Li,Bin-Gui Wang

doi:10.3390/md19010009

Abstract

Three new phenylhydrazones, penoxahydrazones A–C (compounds 1–3), and two new quinazolines, penoxazolones A (compound 4) and B (compound 5), with unique linkages were isolated from the fungus Penicillium oxalicum obtained from the deep sea cold seep. Their structures and relative configurations were assigned by analysis of 1D/2D NMR and mass spectroscopic data, and the absolute configurations of 1, 4, and 5 were established on the basis of X-ray crystallography or ECD calculations. Compound 1 represents the first natural phenylhydrazone-bearing steroid, while compounds 2 and 3 are rarely occurring phenylhydrazone tautomers. Compounds 4 and 5 are enantiomers that feature quinazoline and cinnamic acid units. Some isolates exhibited inhibition of several marine phytoplankton species and marine-derived bacteria.

Highlights

Microorganisms of different origin may possess unique genomes and potentials that enable them to produce rare metabolites [1,2]
In the investigation towards terrestrial-derived P. oxalicum, an azo compound [3], a diterpene [4], a diphenylmethanone [5], a spiro-oxindole alkaloid [6], isochroman carboxylic acids [3], and polyketides [7] were obtained from soil-derived isolates, several limonoids [8], butyrolactones [9], and isocoumarins [10] were discovered from plant-derived isolates, and alkaloids with 1,3-thiazole and 1,2,4-thiadiazole units [11] were separated from an animalderived isolate
UV and ECD spectra were measured on a Chirascan CD spectrometer

Summary

Introduction

Microorganisms of different origin may possess unique genomes and potentials that enable them to produce rare metabolites [1,2]. As an important class of microorganisms, fungi are substantial sources of striking secondary metabolites with diverse structures and bioactivities. The fungal species Penicillium oxalicum is widespread in terrestrial and marine environments, and its secondary metabolites are abundant. More and more marine-derived P. oxalicum strains were chemically examined. A variety of metabolites including chromones [12,13,14,15] from marineanimal-derived strains, phenolic enamides [16], meroterpenoids [16], and alkaloids [17,18]

Methods

Results

Conclusion