EFFECT OF PLANT EXTRACTS ON ACTIVITY OF STAPHYLOCOCCUS AUREUS BY ELECTROCHEMICAL BIOTESTING

Subject of Research. The paper presents a developed method for rapid instrumental assessment of microbial contamination, as well as pro- and antibiotic properties of pharmacological, food and other products. Method. The developed technique consisted in periodic instrumental registration of changes in pH, redox potential, and electrolytic conductivity of a liquid nutrient medium incubated in the presence and absence of viable test microorganisms and test samples. A comparative analysis of the pro- and antibiotic activity of Staphylococcus aureus was carried out at various concentrations of whole subcritical extracts obtained from ten different types of plant raw materials using liquefied carbon dioxide as an extractant. Main Results. The studies carried out have confirmed that the presented method makes it possible to assess the initial microbial contamination more speedily, objectively and informatively in comparison with the standard one as well as the effect of various samples of pharmaceutical, food and other products on the dynamics of the microorganisms' vital activity. Among the studied samples, the most active prolonged antibiotic properties have been exhibited by extracts from the fruits of Sambucus nigra and Rosa cinnamomea, as well as green leaves of Camellia sinensis at their concentrations in the test medium from 3 vol.% and higher. The most active prolonged probiotic properties have been found in extracts from the Hypericum perforatum herb and green leaves of Camellia sinensis at their concentrations in the test medium equal to 0.2 vol.%. In this case, the biological activity of the tested samples with respect to test microorganisms in the most cases have monotonically decreased with an increase in the interaction time of the mentioned microorganisms and samples. Practical Relevance. The results of this study can find application in the composition development and asse ssment of the properties of new pharmaceutical, food and other products, including various plant extracts. In addition, the proposed method of instrumental microbiological testing can be applicable for control of microbial contamination, as well as pro- and antibiotic properties of various samples of products already accepted for the usage, and individual ingredients and additives to them.