Hydroalcoholic extract of Punica granatum L. (pomegranate) leaf: A promising phytotherapeutic agent against oral pathogens

Dental biofilm (DB) is a complex microbial structure in which implementing an appropriate approach to prevent its development is difficult due to the diversity of microorganisms and the genetic and environmental factors that contribute to its formation. The search for natural products with therapeutic activities has been reported due to their benefits such as lower toxicity, better biocompatibility and more accessible costs when compared to traditional antimicrobials. In this sense, Punica granatum (Pomegranate) has been the focus of studies due to its bioactive compounds. The aim of this study was to develop and characterize a hydroalcoholic extract of Punica granatum leaves (HPE), including the evaluation of its bioactive compound profile, as well as to investigate its antimicrobial and antibiofilm activity against oral pathogens by means of in vitro assays, in addition to testing and evaluating its cytotoxicity, with a view to its potential use as a therapeutic agent in the control of oral infections. To obtain the HPE, leaves of the PG species were collected at coordinates 21°45'51"S. 43°22'55"W macerated in hydroalcoholic solution (50%), and then dried by evaporation. First broth microdilution tests were used an than, tests to inhibit biofilm adhesion and disintegration were carried out to evaluate its antimicrobial properties against Streptococcus mutans and Streptococcus sobrinus biofilms. Raman spectroscopy was used to analyze the molecular interactions present and atomic force microscopy (AFM) to see the homogeneity HPE. The cytotoxicity of HPE on J774A1 cells was evaluated using the MTT assay. HPE exerted significant antimicrobial activity against planktonic cells, monospecie and mixed biofilms. It was able to express bactericidal activity for most strains tested. At the biofilm disintegration assay HPE at 2MIC value was similar to azithromycin. The ability of HPE to inhibit biofilm formation may be related to the presence of phenolic compounds, shown by spectroscopy assays, which have antimicrobial properties. Going ahead, HPE does not express cytotoxicity, instead it improves the viability of macrophages. Future studies are needed to evaluate the pharmacological properties and its efficacy, but the results shown here are promised. • HPE demonstrated antimicrobial activity against oral microorganisms. • Phenolic compounds in pomegranate leaves is correlated with antimicrobial efficacy. • Pomegranate leaves is a potential source of new oral antimicrobial agents. • The study contributes to potential natural alternatives against oral infections.