Green ultrasound-assisted extraction of lichen substances from Hypotrachyna cirrhata. Ethyl lactate, a better extracting agent than methanol toxic organic solvent?

For the first time, we report a green extraction of lichen substances assisted by high power ultrasounds from Hypotrachyna cirrhata using ethyl lactate. This sustainable alternative was comparable, both in isolation and detection of lichen substances, to methanol. In the metabolomic analysis, a total of 77 lichen substances were detected comprising depsides, depsidones, dibenzofurans, organic acids, and lipids. Although the UHPLC/ESI/MS profiles were similar, the antioxidant activity was higher for the ethyl lactate extract. Ethyl lactate can replace toxic organic solvents, such as methanol, in order to provide more sustainable green chemistry methods.