Endophytes: Potential Source of Therapeutically Important Secondary Metabolites of Plant Origin

Use of plants and plant-derived metabolites for human health and well-being is as old as human civilization. The plant kingdom contains an estimated 400,000–500,000 different species and each plant produces a number of secondary metabolites which enables them to withstand various biotic and abiotic stresses. The plant secondary metabolites such as alkaloids, steroids, flavonoids, terpenoids, etc., are known to have a number of biological activities. Moreover, because of their natural origin, the plant-derived metabolites are increasingly preferred for therapeutic applications all over the world. However, the overharvesting of plants for biologically active secondary metabolites is rapidly diminishing the valuable treasure of medicinal plants. Endophytes are the microbial symbionts which live in the internal tissues of plants and mimic the chemistry of the host plant. Because of their huge diversity and ability to produce a range of metabolites similar to host plant, they have attracted significant attention of scientific community all over the world. The plant- and endophyte-derived metabolites which have attracted sufficient research in last decade include compounds with antioxidant, antihypercholesterolemic, antidiabetic, and anticancer activities. The present article reviews the current state of research on biologically active metabolites from plant and endophytic fungi. The work carried out in our lab on bioprospecting of endophytic fungi for molecules with antihypercholesterolemic potential is also included.