Determination of Antimicrobial Activity of Various Extracts of Stinging Nettle (Urtica dioica)

Urtica dioica, or stinging nettle, is traditionally used in much frequency in northern Iran. A total of nine extracts were prepared using different organic solvents and by two extraction methods, either by using soxhlet extractor or sequential partitions. The antibacterial and antifungal activities of crude extracts were tested. The main purpose of this study was to determine and compare two methods of extraction and the ability of different kinds of U. dioica crude extracts to inhibit various pathogenic microorganisms. A selection of extracts that showed any activity was further tested for the minimal inhibitory concentrations (MIC) on nutrient agar and minimal bactericidal concentrations (MBC) on Muller-Hilton agar. Only one extract, ethyl acetate extract of Method II (EAE II) was moderately active against Bacillus cereus, Bacillus subtilis, Vibrio parahaemyticus were 8.33, 8.33 and 0.13 mg/ml for both MIC, respectively. All others were practically inactive. Our finding showed that the method I had high effect on food poisoning bacterial than the method II especially against Bacillus cereus and Vibrio parahaemolytiucus.