Chemical composition, in vitro and in silico activity of the methanolic extract derived from Vassobia breviflora against clinically relevant bacteria.

Abstract

This study aimed to identify chemical compounds derived from Vassobia breviflora methanolic extract using ESI-ToF-MS and their antioxidant potential activity utilizing the following methods: total phenols, DPPH, and ABTS^•+. The MTT assay measured cytotoxic activity, while DCFH-DA and nitric oxide assays were employed to determine reactive oxygen species (ROS) and reactive nitrogen species (RNS) levels using African green monkey kidney (VERO) and human keratinocyte (HaCat) cell lines. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were assessed in seven clinical isolates and nine ATCC strains. Biofilm inhibition was tested against four biofilm-forming strains. The antioxidant properties of the methanolic extract were identified as follows: 35.74 mg GAE/g (gallic acid equivalents)/g for total phenols, 10.5 µg/ml for DPPH, and 50.68 µmol trolox/µg for ABTS^•+. The mean inhibitory concentration (IC₅₀) values were 622.86 µg/ml (VERO) and 784.33 µg/ml (HaCat). These concentrations did not markedly alter levels of ROS and RNS. Conversely, Bacillus cereus β-hemolytic displayed higher sensitivity to the extract, with MIC of 64 µg/ml and MBC of 128 µg/ml. Enterococcus faecium exhibited the lowest biofilm formation among the tested bacteria. The studied plant exhibited activity against all bacterial strains at concentrations lower than the IC50 VERO and HaCat cells, suggesting potential for future studies. Data present a comprehensive molecular docking analysis against the HlyIIR protein (PDB ID: 2FX0) and determined antimicrobial and endocrine-modulating potentials. Notably, lancifodilactone I and nicandrin B demonstrated the strongest binding affinities, with binding energies of -9.8 kcal/mol and -8.3 kcal/mol, respectively, and demonstrated significant antimicrobial effects against B. cereus. In addition, several compounds showed potential interactions with nuclear receptors, indicating potential endocrine-modulating effects. These findings provide insights into developing target-specific antimicrobial therapies and endocrine-modulating agents.