Fungal Endophytes from Medicinal Plants as a Potential Source of Bioactive Secondary Metabolites and Volatile Organic Compounds: An Overview

Abstract

In this chapter, we provide a general overview of secondary metabolites, especially easily volatilized molecules, namely, VOCs, isolated and identified from endophytic fungal communities of different medicinal plants. A fungal endophyte spends the whole or part of its life cycle colonizing inter- and/or intracellularly inside the healthy tissues of the host plants, causing no apparent symptoms of disease. Endophytic fungi produce a wide array of secondary metabolites and volatile organic compounds with important biological functions, displaying a broad range of useful antibiotic and pharmaceutical activities as well as immunomodulatory and toxic activities. Some of their biological activities are still unknown to mankind. These microbial metabolites have drawn enormous attention as potential agents of medicinal properties. Fungi are well known for emitting a complex mixture of volatile organic compounds (VOCs). Fungal VOCs commonly form a bioactive interface between plants and numerous microorganisms. Fungi emit plethora of unique volatile compounds that belong to a number of chemical classes including alcohols, aldehydes, acids, ethers, ketones, hydrocarbons, terpenes, and sulfur compounds. VOCs are gases, carbon-based compounds having characteristic odors, and are produced during primary and secondary metabolism. The diverse functions of fungal VOCs can be used in biotechnological applications as biofuel, biocontrol, and mycofumigation.