Coriolus versicolor Mushroom Grown on Selenium-Rich Zeolite Tuff as a Potential Novel Food Supplement

Abstract

Research background. In the recent years, considerable attention has been given to selenium (Se) status since its deficiency is linked with various disorders and affects at least 13 % of world population. Additionally, mushrooms are known to possess pronounced capacity for absorption of various micronutrients, including Se, from soil/substrate. Here, the possibility of using Se-rich zeolite tuff as a supplement for production of selenized mushroom is investigated. Further, the impact of enrichment on the activity of antioxidant enzymes and biological potential of Coriolus versicolor medicinal mushroom is studied. Experimental approach. Se(IV)- and Se(VI)-modified natural zeolitic tuff from the Serbian deposit Zlatokop was used as substrate supplement in mushroom cultivation. To examine effectiveness of selenium enrichment, beside inductively coupled plasma mass spectrometry (ICP-MS) analysis of total selenium content, determination of antioxidant enzymes in fresh fruiting bodies as well as testing of biological potential of methanol extracts was done. Antioxidant activity was evaluated using tests pertaining to different ways of antioxidant action: inhibition of lipid peroxidation, DPPH free radical scavenging assay, ferric-reducing antioxidant power assay and chelating ability on ferrous ions. The antibacterial activity against foodborne pathogens was measured by broth microdilution assay. Additionally, chemical composition of prepared extracts was studied using UV-Vis and FTIR spectroscopy analyses. Results and conclusions. Content of selenium detected in biofortified C. versicolor was even 470 times higher compared to control ((140.7±3.8) vs (0.3±0.1) µg/g dry mass), proving that Se-rich zeolite tuff is excellent supplement for mushroom production. Further, the results of monitoring the activity of antioxidant enzymes revealed that most of the Se-enriched mushrooms exhibited higher superoxide dismutase (SOD) and catalase (CAT) and lower glutathione peroxidase (GSH-Px) activity than control. Due to elevated level of enzymes, selenated mushrooms could quickly respond to superoxide radicals, formed as a result of detachment, and thus presumably preserve quality for a longer period of time. Investigation of biological potential indicated that Se-enriched mushroom methanol extracts, generally, expressed enhanced antioxidant properties. Additionally, extracts asserted antibacterial activity against all tested pathogenic microorganisms. Novelty and scientific contribution. Cultivation of mushrooms on Se-enriched zeolite tuff is a new technological approach for obtaining Se-fortified food/supplements with enhanced antioxidant and antibacterial activity.