Root tuber extract of <i>Polygooum cillinerve</i> (Nakai) Ohwi exerts antimicrobial and immunomodulatory activities

Abstract

Purpose: To investigate the antibacterial and immunomodulatory activities of the root tuber extract of Polygonum ciliinerve (Nakai) ohwi, a traditional Chinese medicine. Methods: Minimum inhibitory concentrations (MICs) of root tuber extract of Polygonum ciliinerve (Nakai) ohwi (rPC) and the synergistic effects between rPC and antibiotics were evaluated by broth dilution. In vitro adhesion and invasion assays were used to determine the effect of rPC on bacterial adhesion and invasion. Furthermore, the immunomodulatory effects of rPC were assessed by western blot. Results: rPC treatment inhibited the growth of Staphylococcus aureus (MIC = 12 mg/ml) and Escherichia coli (MIC = 64 mg/mL). rPC also showed synergistic effects with penicillin (fractional inhibitory concentration, FIC = 0.45), vancomycin (FIC = 0.333), moxifloxacin (FIC = 0.25), and levofloxacin (FIC = 0.356). The adhesion and invasion of bacteria were also suppressed by rPC treatment. Moreover, rPC exhibited an immunomodulatory effect during bacterial infection. Conclusion: rPC shows antibacterial and immunomodulatory activites when assessed by multiple methods, and therefore is a potential therapeutic alternative agent for the treatment of bacterial infections.