Endophytic fungi from medicinal plants: a treasure hunt for bioactive metabolites

Endophytic fungi are ubiquitous organisms found in the plants, residing intercellular or intracellular, at least for a portion of their lives without causing apparent symptoms of infection. Almost all plants are known to harbor endophytes. The choice of the plant to be used for exploring endophytes for bioactives is important. Therefore, medicinal plants which are known to be used since centuries as an alternative source of medicine, are a valuable source for bioprospecting endophytes. Nevertheless, due to many reasons there is a dire need for novel resources for novel drugs which can be an answer to many deadly diseases. It is in this context that the present review was envisaged. The review reveals the importance of endophytic fungi from medicinal plants as a source of bioactive and chemically novel compounds. The bioactive metabolites produced by endophytic fungi originate from different biosynthetic pathways and belong to diverse structural groups such as terpenoids, steroids, quinones, phenols, coumarins etc. Endophytes therefore, represent a chemical reservoir for new compounds such as, anticancer, immunomodulatory, antioxidant, antiparasitic, antiviral, antitubercular, insecticidal etc. for use in the pharmaceutical and agrochemical industries. Although, efforts have been made to accommodate as many examples as possible but the depth of the subject is so vast that it cannot be covered in one single review. This in itself speaks of the fact that endophytic fungi from medicinal plants is indeed a treasure worth searching. In the present review only some selected examples have been covered.