Changes in the biochemical compounds of Vaccinium myrtillus, Vaccinium vitis-idaea, and forest litter collected from various forest types

The aim of this study was to evaluate the impact of forest clear-cutting on the phenolic compounds and antiradical activity of Vaccinium myrtillus, Vaccinium vitis-idaea, and forest litter collected during the vegetation stages in 2 forests types (Pinetum vacciniosum and Pinetum vaccinio-myrtillosum). The Folin-Ciocalteu method, aluminum trichloride colorimetric assay, and 2,2-diphenyl-1-picryihydrazyl (DPP11) test were applied to perform the total phenolic content (TPC), total flavonoid content (TFC), and antiradical activity analyses of the extracts of the underground and aboveground parts of the plants and forest litter. The TPC content varied from 35.87 to 229.76 mg/g (expressed as rutin equivalents) and 120.03 to 309.64 mg/g in the aboveground extracts of V. myrtillus and V. viiis-idaea, respectively. Remarkably lower amounts of phenolic compounds were determined in the underground extracts of the tested shrubs. The TPC content in the forest litter ranged from 3.12 to 11.89 mg/g. The radical scavenging activity (RSA) varied from 3.12 to 434.68 mg/g; the lowest antiradical activity was determined in the underground extracts, while the highest was in the aboveground extracts of V myrtillus. The TFC was dependent on the vegetation phase, forest type, and clear-cutting, and varied from 7.97 to 40.18 mg/g in the aboveground extracts of the tested plants. Flavonoids were not detected in the underground extracts of the samples or in the forest litter. The chemometric analysis revealed statistically significant trends of environmental impact on V myrtillus and V vitis-idaea at the different vegetation stages. Hypotheses testing showed that the TPC, TFC and RSA expressed statistically significant (alpha <= 0.05) changes in 68%, 60% and 71% of the tested samples after clear-cutting, respectively.