Enterococcus species are Gram-positive cocci normally found in the gut but have emerged as opportunistic pathogens in healthcare settings, with rising multidrug resistance, particularly vancomycin-resistant Enterococci (VRE) posing major therapeutic challenges. This study evaluated the antibacterial and synergistic effects of plant-derived stilbenes from Reynoutria japonica against clinical VRE isolates. Ten clinical Enterococcus faecalis isolates were identified using standard morphological, biochemical, and Gram-staining methods, and antibiotic susceptibility testing. The antibacterial activity of polydatin, resveratroloside, and trans-resveratrol was assessed by agar well diffusion, and evaluation of minimum inhibitory concentrations (MICs) and evaluation of bactericidal activity concentrations (MBCs), with synergistic effects tested in combination with vancomycin.Molecular docking was performed with DapF, vanA, and gelE proteins. All isolates were resistant to vancomycin, ampicillin, imipenem, gentamicin, and ciprofloxacin but sensitive to linezolid. All three stilbenes displayed antibacterial activity. Notably, trans-resveratrol was the most active compound, with a MIC value of 0.156 mM and bactericidal activity (an MBC value equal to the MIC). Furthermore, all compounds exhibited synergistic effects when combined with vancomycin. Phytochemical analysis confirmed these stilbenes as major constituents in the root extract of R. japonica. Molecular docking studies revealed strong binding affinities of the compounds to key virulence and resistance-associated proteins (DapF, VanA, and GelE). These results indicate that transresveratrol and related stilbenes are promising candidates for development as alternative or adjunct therapeutic agents against VRE infections. Additionally, this study substantiates the traditional use of R. japonica as a source of bioactive antimicrobial compounds.

In recent times, the emergence of Clostridium perfringens has posed a significant challenge to public health due to its antibiotic resistance and the formation of biofilms. It is the neuraminidase enzyme that supplies toxin secretion from C. perfringens. Since the sialic acid bond is a target recognition point for bacteria, new molecules are needed to treat infections caused by dangerous pathogens such as C. perfringens.The present work focused on an alternative strategy using compounds from Polygonum cuspidatum Sieb. et Zucc. Nine bioactive compounds derived from this plant emodin, physcion, emodin-1-O-β-D-glucopyranoside, emodin-8-O-β-D-glucopyranoside, physcion-8-O-β-D-glucopyranoside, 2-methoxy-6-acetyl-7-methyl juglone, torachrysone-8-O-β-D-glucoside, polydatin and resveratrol were used as ligands and coupled. The neuraminidase enzyme from C. perfringens was chosen as the target protein. The optimal ligand insertion score and ADMET parameters were determined by employing the Lipinski rules as selection criteria. Emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside exhibited drug-like characteristics in their ability to inhibit neuraminidase, as evidenced by a chelation score of −11.9. A comparison was conducted between emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside, and the positive control quercetin.A comprehensive analysis of the drug-like properties of emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside revealed that exhibited superiority over quercetin across multiple aspects. Quercetin showed a binding affinity of −9.9, while emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside showed a binding affinity of −11.9. The results showed acceptable differential kinetic properties of emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside compared to quercetin. It has been shown to inhibit the neuraminidase enzyme from C. perfringens.