Antimicrobial and antipathogenic activity of Fallopia japonica leaves alcoholic extract

The aim of the study consists in the investigation of the antimicrobial and antiphatogenic activity of ethanol extracts obtain from F. japonica leaves. Total phenolic content was determined by Folin-Ciocalteu method, while their phenolic composition was specified by HPLC. In vitro antimicrobial activity of various concentrations ranging from 6.25 to 200 mu L/mL of alcoholic (ethanol 70%) extract of F. japonica were analyzed on different clinical and reference bacterial strains (Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumanii) and fungal strains belonging to Candida spp. using agar disk diffusion method and broth dilution method. The anti-pathogenic properties were studied by determining the adhesion capacity of microbial strains to inert substrate. The soluble virulence factors were quantified using specific media with different biochemical substrats for revealing haemolysins, lecithinase, gelatinase, lipase, DN-ase, amylase and iron chelating agents. The antibiogram adapted technique assesseded the synergic effects of F. japonica leaves extracts with the clinical used antibiotics for different bacterial strains. The studied extract showed the best antimicrobial activity against P. aeruginosa (6.25 mu L/mL) due to phenolic compound identified (epicatechin, rutin and quercetin). In the Gram-positive strains' case were observed phenotypic changes in the DNA-ase and lechitinase enzymes expression. In the antibioresistance pattern profiling it was observed that F. japonica leaves improved the Kanamycin activity for S. aureus, Colistin for P. aeruginosa and Meropenem for A. baumanii. In this respect, could be assumed that this extract could be used complementarily with antibiotherapy, by inhibiting the specific virulence factors.