Antioxidant Properties of Parmeliaceae Lichens with Different Levels of Anthropo-Tolerance

Abstract

A complex analysis of the antioxidant properties of four epiphytic lichen species from the Parmeliaceae Zenker family with different anthropo-tolerance has been carried out. The antioxidant activity and the contents of phenolic compounds (PC) and carotenoids have been determined in Evernia divaricata (L.) Ach., E. prunastri (L.) Ach., Hypogymnia physodes (L.) Nyl., and H. tubulosa (Schaer.) Hav. using DPPH, FRAP, and ABTS methods. Correlation analysis showed a close relationship between the PC and carotenoids and the antioxidant activity (AOA). A multi-parameter biochemical sensitivity index (MPBSI) based on normalization of the values of these biochemical parameters has been calculated. The tolerance of species resistant to anthropogenic pollution was due to higher concentrations of PC and carotenoids and higher AOA. The MPBSI of Hypogymnia physodes was 8.43; of Evernia prunastri, 6.38. Species sensitive to various anthropogenic impacts were characterized by lower values of these parameters. The MPBSI of Hypogymnia tubulosa was 5.83; of Evernia divaricata, 1.56. The degree of the decrease in the MPBSI correlated with the level of vulnerability due to vegetation transformation resulting from woodland fragmentation, which led to changes in the microclimate. Photoprotection in Evernia species that have a bushy biomorph was due to a higher concentration of carotenoids. An increase in antioxidant activity in Hypogymnia representatives with leafy thalli was due to an increase in the PC content. A complex approach to the assessment of the biochemical parameters related to the antioxidant properties, with the determination of the values of the MPBSI index, was interesting for the further development of biomonitoring studies. This approach would make it possible to delve into the scales of anthropo-tolerance and would help clarify the mechanisms of adaptation of lichens to different types of anthropogenic impacts.