Comparison of Different Extracts of Nettle in Quercetin and Evaluation of its Antimicrobial Activity

Nettle (Urtica dioica L.) is one of the most well-known medicinal plants. It has been mostly used for medical purposes. This study summarizes extensive results on the antimicrobial effect of Urtica dioica L. The aim of this study was to investigate several extraction methods of nettle extract for more access to flavonoid materials especially quercetin. For this purpose, three methods (soaking, sonication, soxhlet) and three solvents (chloroform, methanol, deionized water) were used for extraction. Finally, the highest amount of quercetin determined by HPLC was sonication for 90 min with methanol solvent. The effect of this extract was investigated on several pathogenic microbes including Escherichia coli, Entrecoccus faecalis, Klebsiella pneumoniae, Acinetobacter calcoaceticus, Candida albicans. Antibiogram testing revealed that Escherichia coli and Candida albicans were resistant to nettle extract, Acinetobacter calcoaceticus and Klebsiella pneumonia, were sensitive and Enterococcus faecalis was semi-susceptible.