Cytotoxic activity of supercritical CO2 extract of old man's beard in L929 fibrosarcoma cell line

Abstract

Old man’s beard (Usnea barbata) is one of the most investigated lichens which biological properties (such as antimicrobial, anti-inflammatory and cytotoxic activities) have been proven in several scien- tific studies. Stated properties of old man’s beard have been attributed mainly to its major secondary metabolite - a dibenzofuran derivative, usnic acid. The aim of the current study was to examine cyto- toxic activity of the quantified supercritical CO2 extract and pure usnic acid in parallel against L929 fibrosarcoma cells. Our results indicated the tested extract to be more toxic towards the investigated cell line compared to usnic acid per se, despite the high amount of this compound (81.41% (w/w)) revealed in the extract using HPLC. Such result may be connected to the unidentified compounds present in the supercritical CO2 extract that could be responsible for apoptosis and oxidative stress in the exerted cytotoxicity of the investigated extract, but not usnic acid. Our study supports further in- vestigations of supercritical CO2 extract of U. barbata as a prospective therapeutic agent with potential relevance in the treatment of sarcoma.