ABSTRACT

Lichens are complex symbiotic associations between a fungus (mycobiont) and photobiont, which can be either an alga or cyanobacteria. They are proven as the earliest colonizers of terrestrial habitats on the earth with a worldwide distribution from the Poles to tropical regions and from the plains to the highest mountains.

In this study, the antartic lichen Usnea aurantiaco-atra has been characterized morphologically as well as structurally. A phytochemical study has been carried out, aiming to explore the most important metabolites. Moreover, the cytotoxic, antioxidant and insecticidal activity of their extracts has been determined.

Citotoxicity studies have found that the hexanic extract that contains usnic acid as its main metabolite, linoleic acid and terpenes proved to have an interesting citotoxic activity when compared to melanoma and queratinocites.

Testing the extract’s insecticidal activity in Ceratitis Capitata has demonstrated that usnic acid is linked to flies’ mortality. However, the results obtained with different extracts cannot be considered significant. On another note, we have analyzed the presence of total phenols in the extracts and we have seen that they do not have a significant influence in their antioxidant activity.