Comparison of antimicrobial activity of traditionally used herbal uroantiseptics against clinical isolates of uro-genital pathogens

In present study, we compared the antimicrobial activity of ethanolic extracts of four traditionally used drugs in the treatment of urogenital infections (Ericaceae flos, Myrtilli folium, Uvae ursi folium, Vitis ideae folium) [1] with arbutin, hydrochinone, and the commonly used uroantiseptic norfloxacin. The activity against clinical isolates of the most common urinary pathogens was evaluated against gram-negative (Escherichia coli p-fimbriae positive-strains, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa) and gram-positive bacterial species (Enterococcus faecalis, Staphylococcus aureus), as well as against the yeast Candida albicans, using hole plate diffusion and broth dilution methods. In general, the activity of the extracts was species-dependent. In hole plate diffusion method, the extracts of Uvae ursi folium and Myrtilli folium showed stronger bactericidal activity than the rest of the extracts with average inhibition zones of 28.47 and 25.47mm, respectively. In the same method none of the extracts showed noticeable antifungal activity against Candida albicans. Using broth dilution method minimal inhibitory concentrations (MICs) were determined. All the investigated bacterial species were sensitive to the extracts with MICs below or equal to 10.42mg/mL while the MIC values for the isolates of C. albicans yeast were between 8.33 and 25mg/mL. The highest activity was demonstrated by Uvae ursi folium extract against E. faecalis (MIC 2.60mg/mL) and P. aeruginosa strains (3.13mg/mL). The antimicrobial activity of the extracts was lower than the activity of hydrochinone and norfloxacin, but higher than arbutin. Statistical analysis did not reveal clear correlation between content of arbutin, methylarbutin, polyphenols or tannin in extracts and in vitro MIC values. However, the extracts with higher amount of investigated substances tended to be more active in both methods. The results of the study confirm the justifiability of use of these drugs in treatment of urinary infections caused by investigated bacterial species.

Reference: 1. Kustrak, D. (2005) Farmakognozija-Fitofarmacija. Golden Marketing-Tehnicka knjiga. Zagreb