ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF Hypogymnia physodes METHANOL EXTRACT AND ITS CONSTITUENTS. 3-HYDROXYPHYSODIC ACID, A POTENT NATURAL ANTIOXIDANT.

Hypogymnia physodes is known as dye source, as human food and as medicine. Since it is used as a food it is important to know are there any more beneficial effects on human organism and which compounds are responsible for these activities. Therefore, in this study the antimicrobial and antioxidant activities of H. physodes methanol extract (ME) and its constituents: depsidones, physodalic acid (I), physodic acid (II), 3-hydroxy physodic acid (III), and depside atranorin (IV) were investigated. To the best of our knowledge this would be the first information of antioxidant and antimicrobial activity of physodalic acid (I). All the tested components and extract showed antibacterial and antioxidant activities. Antifungal activity was not observed for the tested depsidones. The most sensitive, among bacteria was S. aureus and the highest resistance was shown by E. coli and P. aeruginosa. Only ME and atranorin were active toward C.albicans while A. niger was resistant on all tested samples. Among the analysed samples, compound III has the highest antioxidant capacity in all antioxidant experiments. Compound III showed higher antioxidant activity than commercial antioxidant BHT. The hydroxyl group in position 4 of dibenzo[b,e][1,4] dioxepine core can be of importance for its potent antioxidant activity. [ABSTRACT FROM AUTHOR]