Lichen substances and their biological activities

Abstract

Lichens are known to synthesize variety of secondary metabolites which show wide range of biological activities. Many substances have been successfully isolated and identified from natural thalli and mycobiont cultures. Various biological activities have been screened for chemicals produced by mycobionts in culture medium and natural thalli of lichens. In a study conducted two decades back, lichen substances and their biological activities were reviewed, in which were thirty-nine lichen products, mainly novel phenolic compounds, synthesized by mycobiont cultures. Here, we review studies regarding synthesis of lichen substances by liquid cultures of lichen mycobionts, new sophisticated analytical methods for isolation and characterization of lichen substances, and various sensitive bioassays to assess the bioactivity of the isolated compounds. Biological properties of mycobiont cultures and natural thalli of lichens for range of potential bioactivity as anti-oxidation, inhibitions of monoamine oxidase, acetylcholinesterase, and photosynthesis, and growth inhibitions of animal-diseased bacteria, wooddecaying fungi and tumor cells have been discussed in detail.