A Review on Lichen: The Oldest Symbiotic Relationship

Abstract

Lichens are best understood as self-sustaining ecosystems resulting from interacting with a fungus, one or more photosynthetic organisms, and numerous other microscopic entities. The fungal component provides an overall structure and scientific nomenclature. These associations were the first to be described as symbiotic and considered mutualistic, as all participants benefit by enabling the colonization of new environments. This text outlines the current economic and traditional uses of lichens, highlighting the various natural compounds they produce, some of which show potential for pharmaceutical applications.