JOURNAL OF FOOD PROCESSING AND PRESERVATION, cilt.37, ss.1103-1110, 2013 (SCI İndekslerine Giren Dergi)
In this study, the methanolic extracts and lichens acids obtained from six Umbilicaria species were tested for their antimicrobial activity (against three Gram-positive bacteria, five Gram-negative bacteria and two yeasts species) and their antioxidant activity. Total phenolic content in the extracts was determined by the Folin-Ciocalteu assay. It ranged from 0.91 to 48.25mg gallic acid/g. The antioxidant ability was measured using a free radical-scavenging activity assay using 2,2-diphenyl-1-picrylhydrazyl (DPPH). The methanolic extracts showed moderate DPPH radical-scavenging activity. Among the lichen acids, umbilicaric acid showed the highest antioxidant activity with 68.14% inhibition. Antimicrobial activity was determined by the agar diffusion method. Extracts were found to possess antimicrobial activity against some of the bacteria and yeasts tested. Gyrophoric acid was effective against six out of eight bacteria tested, but no activity was observed against the yeasts.