Study of antimicrobial activity of Zinnia elegans raw materials

Abstract

Introduction. This work is a logical continuation of the study of raw materials of Zinnia elegans Jacq., Asteraceae family, which we started in previous works devoted to phytochemical study. For a comprehensive and in-depth study of this plant, it was appropriate to pay attention to the types of pharmacological activity. From a review of the literature, it is known that representatives of the genus Zinnia L. have antimicrobial and antifungal activity. In particular, foreign scientists investigated the antimicrobial properties of ethyl acetate and hexane extracts from Zinnia peruviana (L.) L. raw materials. Their pronounced antimicrobial activity against Staphylococcus aureus ATCC 43300, Pseudomonas aeruginosa ATCC 27853, Listeria monocytogenes CLIP 74910, Escherichia coli and Bacillus cereus was established. Other studies have also been carried out on the study of acetone extracts of leaves, flowers and roots of Zinnia peruviana. It was determined that the most effective extract, showing pronounced antimicrobial activity, was the root extract. In addition, studies of ethanolic extracts from the leaves of Zinnia elegans in various concentrations were conducted to inhibit the growth of some putrefactive fungi. The results are encouraging, therefore it is urgent to carry out a more detailed study of antimicrobial activity of various types of Zinnia elegans raw materials. The aim of the work was to study the antimicrobial activity of the raw material of Zinnia elegant. Materials and methods. For the experiment, we used herb, leaves, flowers and stems of Zinnia elegans, which were harvested in the flowering phase in Ukraine (Kharkiv region) in August 2021-2022. The raw material is a mixture of Karusel and Rozhevyi briliant varieties. To carry out the experiment, a weight of raw material crushed into powder was placed in a conical flask and an extractant (water and ethanol of different concentrations) was added. The ratio of raw materials: extractant is 1:5. It was insisted for 1 hour at room temperature, then the extracts were filtered and concentrated to thick extracts. In accordance with WHO recommendations, test strains of Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis ATCC 6633, Proteus vulgaris ATCC 4636, Candida albicans ATCC 885/653 were used to evaluate the activity of the drugs. The microbial load was 107 microbial cells per 1 ml of medium and was determined according to the McFarland standard. An 18-24-hour culture of microorganisms was used for work. Muller-Hinton agar was used for research. The method of drug diffusion in agar was carried out by "wells". When evaluating antimicrobial activity, the following criteria were used: the absence of growth retardation zones of microorganisms around the hole, as well as retardation zones up to 10 mm indicated that the microorganism is not sensitive to the drug; zones of growth retardation with a diameter of 10-15 mm indicated low sensitivity of the culture to the drug; zones of growth retardation with a diameter of 15-25 mm were considered as an indicator of the sensitivity of the microorganism to the drug; zones of growth retardation, the diameter of which exceeded 25 mm, indicated the high sensitivity of the microorganism to the drug. For a more detailed study of the antimicrobial activity of samples of Zinnia elegans raw materials, the antimicrobial activity of the drug Chlorophyllipt, which is a well-known antibacterial agent, was also determined to compare the activity. Research results. Staphylococcus aureus, Bacillus subtilis, and Escherichia coli were largely sensitive to extracts from herb, leaves, flowers, and stems obtained with 96% ethanol. In addition, it should be noted that the growth retardation zones of Bacillus subtilis under the influence of flower extract were at the same level as Chlorophyllipt. As for the extracts of Zinnia elegans raw material obtained with 70% ethanol, the largest zones of growth retardation were noted in Staphylococcus aureus, while they corresponded to the diameter of the growth retardation zones obtained under the influence of Chlorophyllipt. Regarding the activity of the extracts obtained with 40% ethanol, they were inferior to the extracts obtained with 70% and 96% ethanol, but Staphylococcus aureus and Bacillus subtilis were also sensitive to their action. It should be noted that the growth retardation zones of Bacillus subtilis were at the same level both under the influence of extracts obtained with 70% ethanol and those obtained with 40% ethanol. Unlike Chlorophyllipt, Proteus vulgaris and Pseudomonas aeruginosa were also sensitive to the action of extracts obtained with 96% and 70% ethanol. As for the extracts obtained with 40% ethanol, these microorganisms showed low sensitivity. Aqueous extracts of Zinnia elegans raw materials were ineffective as antimicrobial agents. Staphylococcus aureus showed little sensitivity to their action. All other microorganisms were not sensitive to aqueous extracts obtained from the studied species of Zinnia elegans raw materials. Therefore, extracts from herb, leaves, flowers and stems of Zinnia elegans, which are obtained with 70% and 96% ethanol, can be considered promising medicinal products. Conclusions. As a result of the conducted research, the antimicrobial activity of ethanolic extracts of herb, leaves, flowers and stems of Zinnia elegans was established. On the basis of the screening, the most appropriate extractants for obtaining medicinal products were determined - 70% and 96% ethanol. These data can be used in the future in the development of new domestic medicines.

Keywords: Zinnia elegans, raw materials, antimicrobial activity