Evaluation of antimicrobial activity of dosage forms based on Michurin's chokeberry leaves

Introduction. Recently, researchers have shown great interest in studying the phytochemical composition of Michurin's aronia leaves (Aronia × mitschurinii A.K. Skvortsov & Maitul) due to the significant content of such valuable biologcally active substances (BAS) as flavonoids, leucoanthocyanins and tannins of the condensed group. Considering the high potential astringent, capillary-protective and anti-inflammatory activity of the main target groups of the BAS of the studied raw materials, in the framework of the present study we have analysed the antimicrobial activity of aqueous-alcoholic liquid extracts of the medicinal forms from Michurin's chokeberry leaves. In our recent studies, we have also established the biocidal effect of the decoction in vitro at a dilution of 1 : 10 on the test system of infusoria Parametium caudatum under the damaging effect of sodium chloride solution in the test "Functional load". Aim. The purpose of the work was to determine the antimicrobial activity of aqueous-alcoholic liquid extraction dosage forms obtained from the leaves of chokeberry Michurin, in order to assess the prospects for creating medicinal herbal preparations (MHRP). Materials and methods. The object of the study were liquid extraction dosage forms, tincture (1 : 5) and liquid extract (1 : 1), obtained from dried leaves of Michurin's chokeberry using 60 % ethanol. The antimicrobial activity of the samples was determined by the double serial dilution method. Staphylococcus aureus, Bacillus cereus, Candida albicans, Escherichia coli , Pseudomonas aeruginosa strains were used as test cultures. The prediction of the main types of pharmacological activity by in silico method was carried out for the pre-identified components of the leaf polyphenolic complex – catechin, rutin and leucocyanidin – using PassOnline and Phyto4Health platform. The medicinal forms obtained were standardised in accordance with the requirements for tinctures and extracts of the State Pharmacopoeia XV edition. Results and discussion. The in silico screening of the main target groups of the BAS of the studied raw materials confirmed their high potential astringent and anti-inflammatory activity. The BAS complex of the liquid extract of Michurin's chokeberry leaves in comparison with the tincture shows antimicrobial activity against Pseudomonas aeruginosa up to the 4 th dilution and antifungal activity against Candida albicans up to the 6th dilution. In relation to such pathogenic microorganisms as Bacillus cereus and Staphylococcus aureus both tested dosage forms showed antimicrobial activity up to the 6 th –7 th dilution. The dosage form with a wider spectrum of antimicrobial activity is the liquid extract. In addition, the obtained dosage forms were standardized according to the requirements of the State Pharmacopoeia of the Russian Federation. Conclusion. The results of the evaluation of the antimicrobial activity of the obtained alcoholic dosage forms based on Michurin's chokeberry leaves (tincture and liquid extract), confirmed the prospects of creating herbal medicines, e.g. for external use in the complex therapy and prevention of diseases of the oral cavity in the form of rinses or applications.