Evaluation of Levofloxacin and Yahom-Navakot Remedy Extract Combination Therapy against Antibiotic Resistant Bacteria.
Keywords:Yahom-Navakot remedy, Levofloxacin, Bacterial antibiotic resistance, Antibacterial activities
Introduction: Antibiotic resistant bacteria are being considered a serious public health challenge. Levofloxacin is a broad-spectrum antibiotic, developed to replace previously resistant antimicrobials. The use of natural products as an antimicrobial drug is an alternative way to reduce bacterial resistance by synthesized drugs and enhance their efficacy. Yahom-Navakot (YN) is a Thai remedy in the Thai essential drug list. The indications for YN treatment are to relieve fatigue, dizziness, malaise, and vomiting after alleviation of fever. Previous studies have reported antibiotic enhancing effects of YN. This study was aimed to evaluate the antibacterial activities of levofloxacin and Yahom-Navakot Remedy Extract.
Methods: YN remedy was macerated with 95% ethanol, after solvent evaporation the extract was combined with levofloxacin (1:1). By using modified resazurin in the broth micro-dilution assay, the antibacterial activities of the combination were evaluated against the pathogenic bacteria; Staphylococcus aureus (DMST 20651), Methicillin-Resistant Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC BAA 2789), Salmonella typhi (DMST 22842), Shigella dysenteriae (DMST 15111), and Escherichia coli (ATCC 25922). P. aeruginosa, MRSA, S. typhi, S. dysenteriae, and E. coli were antibiotic resistant bacteria strains according to WHO criteria. Levofloxacin was used as a control in this study.
Results: In vitro YN extract showed potent antibacterial effect against S. aureus (MIC = 0.625, MBC = 0.39 mg/mL), MRSA (MIC = 0.625, MBC = 25 mg/mL), and S. epidermidis (MIC = 0.3125, MBC = 50 mg/mL). YN extract (At MICs against selected bacteria strains) demonstrated enhanced antibacterial activities of levofloxacin against MRSA (MIC < 3×10-8, MBC < 3×10-8 µg/mL) and S. epidermidis (MIC = 0.048, MBC = 25 µg/mL) as determined by reduced MICs and MBCs. However, it did not affect other selected bacteria strains; P. aeruginosa, K. pneumoniae, S. typhi, S. dysenteriae, and E. coli (MIC > 5 mg/mL).
Conclusions: YN showed evidence of antibacterial activity. It had potential antibiotic enhanced activity with levofloxacin; however, further in vivo and clinical studies are essential to evaluate YN’s efficacy and safety.