Antioxidant Properties and Polyphenol Screening of the Leaves of Native Hungarian Oak (Quercus) Species

Abstract: Due to their ecological significance and timber value, Quercus species are especially important in Hungary. Nevertheless, the leaves of these species lack a dedicated utilization field and are considered a waste biomass. Materials and Methods: The present study comprehensively analyses three selected oak species (Q. petraea, Q. pubescens, Q. cerris) native to Hungary to assess their antioxidant capacity (FRAP, ABTS, DPPH) and provide information on their polyphenol pool using state-of-the-art liquid chromatographic/ tandem mass spectrometric technique. To the best of our knowledge, no such investigation has yet been conducted for the assigned species. Results: According to the results, the antioxidant capacity of the three species’ leaves are roughly equal. Altogether, 109 compounds have been tentatively identified and described, including phenolic acid derivatives, tannins, flavonoid glycosides, and catechins. Compared to other oak leaf samples and other types of plant tissues, the investigated samples contained a large number (24) of acylated polyphenols. Conclusion: The recent findings on the excellent antioxidant and antibacterial properties of acylated polyphenols suggest that the investigated samples could also be beneficial to human health, requiring further analysis.