Lichens have been used as foods, medicines, dyes, and perfumes since ancient times. Many pharmacologically active compounds have been isolated from lichens. However, lichens in nature are rare and seasonal, and harvesting as an industrial resource may lead to the extinction of species. Therefore, to be used in industrial applications, they must be cultured in vitro.
Pharmacological use – Lichens are symbiotic associations composed of fungal (mycobiont) and algal (photobiont) partners. They produce secondary metabolites and have been used as crude drugs. A variety of products isolated from lichens shows a wide range of potentially useful biological activities; e. g. inhibition of prostaglandin biosynthesis, reducing the growth of bacteria, virus, and tumor cells. Therefore, lichens have a very promising aspect for novel pharmaceutical uses.
Environmental use – Lichens grow in extreme environments where other plants can hardly survive such as polar areas, hot deserts, seashores, and high mountains. Thus they play critical roles shaping the environment by photosynthesis. Lichens accumulate high amounts of heavy metals in their thalli and can be used in bio-remediation, or phytoremediation of heavy metal-polluted soil.