Screening of Lichen Extracts Using Tyrosinase Inhibition and Toxicity Against Artemia salina

Abstract

Nine lichen extracts were evaluated for tyrosinase inhibition and toxicity against Artemia salina larvae. Extract compositions were investigated by TLC and NMR analysis. The activity of constituents against tyrosinase was evaluated by bioautography, and the percent of inhibition was calculated based on the dopachrome produced during a set time interval. Cladia aggregata, Cladonia dimorphoclada, Stereocaulon ramulosum and Stereocaulon microcarpum extracts were active for tyrosinase inhibition. Barbatic, usnic, anziaic acids and an unidentified compound present in the extracts, are possibly responsible for tyrosinase inhibition. Cladia aggregata, Cladonia crispatula, Cladonia furcata, Lobaria erosa, Punctelia canaliculata and S. microcarpum proved to be less toxic to A. salina (LC₅₀ > 500 mg/mL) than Cladonia confusa and S. ramulosum (LC₅₀ 45.0 and 100.3 mg/mL, respectively), while the extract of C. dimorphoclada was highly toxic (LC₅₀ < 10 mg/mL).

DOI: http://dx.doi.org/10.17807/orbital.v8i3.842