Antimicrobial activity of extracts of Iris hungarica and Iris sibirica

Abstract

Introduction. Referring to the latest data, infectious diseases command a large part of among the total number of pathologies in the world and are an important problem in medicine. The leading role in prevention and treatment of diseases of microbial origin belongs to antibacterial chemotherapeutic agents. Advantages of antibiotics of synthetic origin are the high activity compared to phytogenic drugs. But it is known that microorganisms can release the resistance to synthetic antibiotics, so the use of drugs based on the plant materials is appropriate: phytogenic drugs more rarely induce the formation of resistance of the strains of microorganisms, they have a gentle action, can be used for a long-term, have the low cost. Therefore, it is appropriate to examine the drug plants with the aim of determination their antibacterial activity.Iris hungarica Waldst et Kit. and Iris sibirica L. are the representatives of the family Iridaceae, genus Iris and they have a wide spectrum of the pharmacological activity. Biologically active substances that were recovered from plants of the genus Iris (tectoridin, iristectorigenin B, nigracin, kaempferol, quercetin, etc.) exhibited an antitumor, antimicrobial, estrogenic, insecticidal, antiplasmatic, anticholinesterase action, they were the inhibitors of enzymes and exhibited the immunomodulatory properties, which made these plants perspective for the research study. Raw materials Irises are constituent components of more than 9 medicines.Materials and Methods. The objects of the study were the leaves and rhizomes of Iris hungarica and Iris sibirica that were prepared during the growing season in 2014 in the M.M.Gryshko National botanical garden (Kiev, Ukraine).The dry and lipophilic extracts from the leaves and rhizomes of Irises were used to establish the antimicrobial activity. For the study of extracts antimicrobial activity was used agar well diffusion method. According to the WHO recommendations the following test-strains were used: Staphylococcus aureus АТСС 25923, Escherichia coli АТСС 25922, Pseudomonas aeruginosa АТСС 27853, Bacillus subtilis АТСС 6633, Proteus vulgaris ATCC 4636, Candida albicans АТСС 885/653. The 18 to 24–hour culture of microorganisms was used for the test. Mueller-Hinton agar was used for bacteria. The strains of Candida albicans were cultivated using Sabouraud agar. Method of serial dilutions was used for the examination of antibacterial properties of selected extracts. The concentration of substances was 1) 1000 µg/ml; 2) 500 µg/ml; 3) 250 µg/ml; 4) 125 µg/ml; 5) 62.5 µg/ml. To each test tube was added of 0.1 ml 10⁹ microbial cells test strains. Examined preparations represented the alcohol and aqueous solutions of the dry and lipophilic extracts of Irises in the different concentrations. Water is the solvent for the dry extracts of Iris hungarica, for the lipophilic – is 70% ethyl alcohol. For dissolution of the dry extracts of Iris sibirica was used water, 70% and 96% ethyl alcohol, for lipophilic extracts – was used 70%, 96% ethyl alcohol. The concentration of the substances was 1.0 % in all experiments. In the capacity of the comparative drug was selected an alcohol solution of chlorophyllipt in the dose of 10 µg/ml («Chlorophyllipt alcohol solution 1%» 100 ml, «GNCLS» Pilot Plant). Results and discussions. The dry extract of the leaves of Iris hungaricaat the concentration 1% has a more pronounced antibacterial activity than the extract of the rhizomes and is the most susceptible to gram-negative bacteria – Escherichiа coli, Proteus vulgaris, Pseudomonas aeruginosa. At that time, as the dry extract of the rhizomes of Iris hungaricaat the concentration 1% is more susceptible to gram-positive bacteria. The lipophilic extracts of the leaves and rhizomes were more susceptibility to gram-positive bacteria. The dry extracts of the leaves and rhizomes of Iris sibirica in aqueous and alcohol solutions have a more pronounced antimicrobial activity against gram-negative bacteria and fungi. The lipophilic extracts of Iris sibirica were more susceptible to gram-negative bacteria. In summary of the results of the examinations "technique of wells" by definition the diameters of growth zones, the antibacterial properties were presented in the lipophilic extracts of the leaves and rhizomes of Iris hungaricaand the dry extracts of the leaves and rhizomes of Iris sibirica. The lipophilic extracts of the leaves and rhizomes of Iris hungaricaand the dry extracts of the leaves and rhizomes of Iris sibirica exhibit a bacteriostatic activity against a wide range of test strains of microorganisms and Candida. Conclusions. Antibacterial properties have been examined of the dry and lipophilic extracts of the leaves and rhizomes of Iris hungarica and Iris sibirica. It has been established that the dry ethanolic extracts and lipophilic extracts from leaves and rhizomes of Iris hungarica and Iris sibirica exhibit an antimicrobial activity against the test strains of microorganisms of the different taxonomic groups. Thus, this examination offers an opportunity to use Iris hungaricaand Iris sibirica as a raw material to produce the substances with antibacterial pharmacological effect for the further development of antimicrobial action.