Biological potential of bioactive metabolites derived from fungal endophytes associated with medicinal plants

Endophytes are endosymbiotic fungi or bacteria that invade and colonize the plant tissue without harming their respective host. Since fungal endophytes live inside the host tissues, their effective isolation and identification is an important step. Endophytic fungi produce bioactive metabolites with unique chemical structures, which may help in improving the physiological condition of both the plants and endophytes. Endophytic fungi are a potent source of all major classes of secondary metabolites including terpenoids, non-ribosomal peptides, polyketides, and alkaloids. With the increase in the number of diseases and human health problems, an intensive search for new sources and effective metabolites is now in progress. The bioactive metabolites produced by the fungal endophytes are competent and effective against various diseases such as cancer, diabetes, infectious diseases, immunological disorders, and cardiovascular diseases. The present review summarizes the efficient approaches used for the screening of fungal endophytes, extraction, and purification of bioactive metabolites along with OMICS based study of endophytes. Along with this, the pharmaceutical importance of novel bioactive metabolites and their efficient production from fungal endophytes using various approaches like genetic engineering, use of elicitors, and precursor feeding are also discussed.