Paper Title
Phytochemical Content and Biological Potential of Some Oak Bark Extracts

Abstract
Recent studies highlight the biological potential of oak species to comprise high contents of bioactive compounds with beneficial effects on human health. The aim of our work is to evaluate the potential biological effects of the bark of two oak species, namely Quercus roburand Q. rubra.The vegetal material was extracted using two extraction methods, namely ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE). The total polyphenolic and tannin contents were quantified using the Folin-Ciocâlteu method. The antioxidant capacity of the extracts was tested using two complementary methods based on the DPPH and ABTS reagents. The antimicrobial activity was evaluated on Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and three fungi from the Candida genus (C. albicans, C. parapsilosis, C. krusei).Higher total polyphenols and tannin yields were observed in the extracts obtained by MAE and ethanol was the better solvent for the extraction of bioactive compounds. Antioxidant activities were highlighted for all the extracts. A better antibacterial activity was observed against the Gram-positive bacterial strains, extracts from the bark of Quercus rubrabeing more efficient. The antifungal activity was highlighted against C. krusei. These results highlight the biological effects of the bioactive compounds found in the oak bark, that may be used in future pharmaceutical formulations. Acknowledgements: This work was supported by a grant of Romanian Ministry of Education and Research, CNS-UEFISCDI, project number PN-III-P1-1.1-TE-2019-1549, within PNCDI III