Shades of fungi - A review of pigments from endophytic fungi

Endophytic fungi are a unique group in the Fungi kingdom as they spend the majority of their life cycles within the living tissue of the host organism without causing apparent harm. The endophyte-host relationship is typically commensalism or mutualistic, with pathogenicity an issue only when either party is under stressed. The contribution of endophytic fungi to the host is mostly in the form of chemical protection - secondary metabolites with bioactivities against invading organisms which may harm the host and consequentially threaten the survival of the endophyte. Many of these chemical compounds have been found to be pigments. Due to easy visual identification, many pigments from fungal sources have been isolated and characterised. This review highlights the potential of endophytic fungi as a source of pigments; with additional focus on significant bioactivity, major chemical classes and biosynthesis. Existing and potential commercial applications of natural pigments by endophytes are also discussed.