Antioxidant, antimicrobial and anti - quorum sensing activities of Rubus rosaefolius phenolic extract.

Abstract

Phenolic compounds are plant secondary metabolites that present many biological effects includingantioxidant and antimicrobial activities. Studies have shown that these compounds can also inhibitquorum sensing bacterial communication. The aim of this study was to characterize the centesimalcomposition, mineral and phenolic content, to determine the antioxidant and antimicrobial effect aswell as the inhibition of quorum sensing by the phenolic extract obtained from wild strawberry (Rubusrosaefolius). Centesimal composition and minerals were in the range expected for fruits of the Rubusgenerum, even though Fe and Zn presented higher levels. The phenolic content was 5902.89 mg GAE/L,also approaching the levels found for fruits of Rubus sp. The antioxidant activity determined throughthe ABTS method was 162.4 ± 5.6 and 120.8 ± 1.5 _M Trolox/g of fruit in the DPPH assay, indicating anelevated potential for ABTS and medium potential for DPPH method. The phenolic extract was able toinhibit all the evaluated bacteria presenting MICs in the range of 491.90–1475.74 mg GAE/L. In sub-MIC concentrations, the phenolic extract inhibited all the phenotypes typically regulated by quorum sens-ing in bacteria, including violacein production, swarming motility and biofilm formation. The phenolicextract of R. rosaefolius presented antioxidant, antimicrobial and anti-quorum sensing activities whichare in agreement with previous studies linking phenolic compounds to these properties.