Fungal Endophytes as an Alternative Natural Resource for the Discovery of Bioactive Compounds of Pharmacological Importance

Fungal endophytes are microorganisms that live in symbiotic relationships with the host plant for at least a part of their life cycle. One or more fungal endophytes are present in every plant across the globe. Fungal endophytes have emerged as a potential natural reservoir for bioactive secondary metabolites to meet the never-ending need for effective treatments. Secondary metabolites are divided into a number of classes, including alkaloids, benzopyranones, chinones, flavonoids, phenolic acids, quinones, steroids, saponins, tannins, terpenoids, tetralones, xanthones, etc. Endophytic fungi such as Alternaria sp., Aspergillus sp., Bipolaris sp., Cephalosporium sp., Chaetomium sp., Colletotrichum sp., Emericella sp., Fusarium sp., Guignardia sp., Hormonema sp., Metarhizium sp., Mucor sp., Paecilomyces sp., Penicillium sp., Phomopsis sp., Talaromyces sp., Taxomyces sp., Tolypocladium sp., Xylaria sp., etc. have been reported to possess potential bioactive compounds. Thus, they are potential sources of several natural drugs available in the market for antibacterial, antifungal, antiviral, antioxidant, anti-inflammatory, anticancer, and antidiabetic agents. This chapter summarizes about various fungal endophytes, their association with plants, and the pharmaceutical application of their secondary metabolites.