Structurally Uncommon Secondary Metabolites Derived from Endophytic Fungi.

Humberto Ortega,Luis Cubilla-Rios,Zuleima Caballero E,Daniel Torres-Mendoza

doi:10.3390/jof7070570

Abstract

Among microorganisms, endophytic fungi are the least studied, but they have attracted attention due to their high biological diversity and ability to produce novel and bioactive secondary metabolites to protect their host plant against biotic and abiotic stress. These compounds belong to different structural classes, such as alkaloids, peptides, terpenoids, polyketides, and steroids, which could present significant biological activities that are useful for pharmacological or medical applications. Recent reviews on endophytic fungi have mainly focused on the production of novel bioactive compounds. Here, we focus on compounds produced by endophytic fungi, reported with uncommon bioactive structures, establishing the neighbor net and diversity of endophytic fungi. The review includes compounds published from January 2015 to December 2020 that were catalogued as unprecedented, rare, uncommon, or possessing novel structural skeletons from more than 39 different genera, with Aspergillus and Penicillium being the most mentioned. They were reported as displaying cytotoxic, antitumor, antimicrobial, antiviral, or anti-inflammatory activity. The solid culture, using rice as a carbon source, was the most common medium utilized in the fermentation process when this type of compound was isolated.

Highlights

Endophytic fungi colonize the internal tissue of plants without causing harm or disease [1]
The homologous sequences of the internal transcribed spacer (ITS1) of the ribosomal gene of different species of endophytic fungi were retrieved from the sequence banks of the National Center for Biotechnology Information (NCBI) through the BLAST® tool
Since the production of secondary metabolites is dependent on culture settings, around

Summary

Introduction

Endophytic fungi colonize the internal tissue of plants without causing harm or disease [1]. They can offer protection against predators, pathogens, and abiotic stresses to their host plant [2,3,4,5]. Endophytic fungi are an important source of active natural products with great chemical diversity which is largely untapped. This biosynthetic capacity and induction for producing secondary metabolites could be related to the activation of genes [8,9]. Many of these compounds possess novel skeletons with antibacterial, antifungal, antiviral, antiinflammatory, antitumor, antimalarial, and other activities, and belong to different classes, such as alkaloids, terpenoids, flavonoids, phenolic compounds, and steroids [10]

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