Antibacterial activity of plants is a subject of interest in the search for new antibiotics and fungicidal preparations. This article analyzes the effectiveness of the action of extracts of plants on microorganisms: six species of bacteria (Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, Klebsiella pneumoniae, Corynebacterium xerosis, Proteus vulgaris) and one fungus (Candida albicans). For the assay, we used herbal material of 50 species (seeds, grass, shoots, leaves, compound fruit, peel) obtained at different periods of the growing season. We studied Levisticum officinale, Petroselinum crispum, Nerium oleander, Vinca minor, Eleutherococcus senticosus, E. sieboldianus, Yucca filamentosa, Artemisia annua, Echinacea purpurea, Matricaria recutita, Tanacetum vulgare, Betula pendula, Corylus avellana, Buxus sempervirens, Humulus lupulus, Crassula ovata, Bryophyllum daigremontianum, Juniperus communis, Platycladus orientalis, Cycas revoluta, Calluna vulgaris, Rhododendron ferrugineum, Ceratonia siliqua, Trigonella foenum-graecum, Ribes nigrum, Phellinus tuberculosus, Lavandula angustifolia, Melissa officinalis, Monarda fistulosa, Origanum vulgare, Salvia sclarea, Laurus nobilis, Punica granatum, Hibiscus rosa-sinensis, Menispermum dauricum, Ficus benjamina, Morus alba, Paeonia suffruticosa, Picea abies, Adonis vernalis, Amelanchier ovalis, Prunus armeniaca, Crataegus monogyna, Citrus sinensis, Salix babylonica, Bergenia crassifolia, Schisandra chinensis, Taxus baccata and Xanthoria parietina. The alcohol tincture was filtered with sterile multi-layer gauze disc filters. Before the discs were put on the surface of agar with inoculation of the corresponding culture, they were dried in a sterile laminar box under ultraviolet rays. Antibacterial activity of various tinctures was determined by the disk diffusion method in agar with the measurement of the diameter of the growth suppression zone of the culture using a template ruler. Maximum inhibiting effect was achieved for Punica granatum on K. рneumonia, L. monocytogenes, S. typhimurium, P. vulgaris, C. хerosis and E. сoli, Lavandula angustifolia – on P. vulgaris, K. рneumonia and S. typhimurium, Echinacea purpurea – on C. аlbicans, E. сoli, P. vulgaris, K. рneumonia, Bergenia crassifolia – on P. vulgaris, K. pneumonia and S. typhimurium.

Galenic preparations are broadly used against microorganisms pathogenic to humans, thought their poteintial in this aspect is not studied completely. In our in vitro experiment we studied the influence of alcohol tinctures from 38 species of plants on 15 species of bacteria and one species of fungus. Zones of growth inhibition of colonies measuring over 8 mm were observed during the use of ethanol extracts of Maclura pomifera against eight species of microorganisms (Escherichia сoli, Proteus mirabilis, Serratia marcescens, Yersinia enterocolitica, Salmonella typhimurium, Rhodococcus equi, Campylobacter jejuni and Corynebacterium xerosis), Ginkgo biloba – against eight species (Enterococcus faecalis, S. marcescens, Y. enterocolitica, Klebsiella pneumoniae, Listeria іnnocua, L. monocytogenes, Р. аeruginosa and C. jejuni), Genista tinctoria – against seven species (E. coli, Enterobacter aerogenes, Proteus mirabilis, K. pneumoniae, S. typhimurium, Р. аeruginosa and Rh. equi), Phellodendron amurense – against seven species (E. faecalis, S. marcescens, S. typhimurium, Rh. equi, C. jejunі, C. xerosis and Candida albicans), Berberis vulgaris – against seven species (P. mirabilis, S. marcescens, K. pneumoniae, S. typhimurium, C. jejuni, Р. аeruginosa and C. xerosis), Vitex negundo – against six species (E. faecalis, E. coli, P. mirabilis, K. pneumoniae, S. typhimurium and Rh. equi), Koelreuteria paniculata – against six species (E. faecalis, P. mirabilis, S. marcescens, S. typhimurium, C. jejunі and E. coli), Magnolia kobus – against six species (E. faecalis, E. coli, P. mirabilis, S. marcescens, S. typhimurium, C. jejunі and C. xerosis), Liriodendron tulipifera – against six species (K. pneumoniae, Listeria іnnocua, Р. аeruginosa, C. jejuni, Rh. equi and C. albicans), Clematis flammula – against six species (E. faecalis, P. mirabilis, L. monocytogenes, Р. аeruginosa, C. jejuni and C. xerosis), Wisteria sinensis – against five species (E. coli, S. typhimurium, L. monocytogenes, Rh. equi and C. albicans), Chimonanthus praecox – against five species (E. faecalis, S. marcescens, L. monocytogenes, C. jejuni and Rh. equi), Colchicum autumnale – against five species (S. marcescens, K. pneumoniae, L. ivanovi, L. monocytogenes and Р. аeruginosa). As a result of the study, these plants were found to be the most promising for further study of in vivo antibacterial activity. In the search of antibacterial and antifungal activities, the following plants were observed to be less promising: Ailanthus altissima, Aristolochia manshuriensis, Artemisia absinthium, Callicarpa bodinieri, Campsis radicans, Catalpa duclouxii, Celastrus scandens, Dictamnus alba, Eucommia ulmoides, Geranium sanguineum, Laburnum anagyroides, Nepeta racemosa, Parthenocissus tricuspidata, Polygonatum multiflorum, Prunus dulcis, P. laurocerasus, Ptelea trifoliata, Pteridium aquilinum, Quercus castaneifolia, Q. petraea iberica, Salvia officinalis, Securigera varia, Styphnolobium japonicum, Tamarix elongata and Vitex agnus-castus.

We have studied the chemical composition and antibacterial profile of ethanolic extract of Punica granatum L. (Lythraceae) on strains of microorganisms in vitro. Analysis using GC-MS showed 5-hydroxymethylfurfural (36.6%), D-sucrose (23.2%), sorbitol (6.7%), palmitic acid β-monoglyceride (5.6%), 2-furancarboxaldehyde (3.5%) and β-D-glucopyranose (3.3%) as the major components of the title extract. The experiment revealed a positive antibacterial effect of extracts obtained from P. granatum on 14 strains specifically Enterobacteriaceae microorganisms (Escherichia coli, Enterobacter aegorenеs, Proteus vulgaris, Serratia marcescens, Klebsiella pneumonia), Listeriaceae (Listeria ivanovi, L. іnnocua, L. monocytogenes) and yeasts from the family Saccharomycetaceae (Candida albicans). Our study showed that in many cases these extracts more intensively affect multi-resistant strains of microorganisms than macrolide antibiotic azithromycin and is therefore a source of molecules to be exploited in medicine or by the pharmaceutical industry. The investigated extracts of P. granatum can be recommended for further in-depth research against poly-resistant strains of the above-mentioned microorganisms. Effective drugs perform a leading role in providing stable veterinary well-being of livestock and healthcare of the population. The present study showed that the studied plant species more intensively affects multi-resistant strains of microorganisms than sodium salt of azithromycin. Lethal concentration (LC50) of ethanol extract from pomegranate for Paramecium caudatum Ehr. equaled 0.3%. Death of 100% of nematode larvae of Strongyloides papillosus (Ihle) was recorded during 24 h exposition in 20% extract of P. granatum peel.

The results of the literature analysis indicate a wide spectrum of biological activity of 1,2,4-triazole derivatives. Low toxicity, reactivity, and high biological activity of 1,2,4-triazole derivatives make this class of compounds very attractive. The obtained data determine the relevance of further studies of 1,2,4-triazole derivatives to find new highly effective biologically active substances that can become the basis for new medicines. Our further work aimed to study some toxicity parameters of 3-(3-fluorophenyl)-6-(4-methoxyphenyl)-7H-[1,2,4]-triazolo-[3,4-b][1,3,4] thiadiazine when administered subcutaneously to guinea pigs, which is a necessary condition for further implementation in practice of this compound. In this work, we observed an absence of toxic effects after a single subcutaneous injection to guinea pigs at a dose of 40 mg/kg experimental drug. The results of macro- and microscopic examinations of internal organs 14 days after a single subcutaneous injection of the studied compound at a dose of 20, 40 mg/kg showed the absence of any anatomical and morphological disorders in the tissue structures of guinea pigs. The calculated value indicates a high degree of safety of 3-(3-fluorophenyl)-6-(4-methoxyphenyl)-7H-[1,2,4]-triazolo-[3,4-b][1,3,4] thiadiazine and its prospects for use in veterinary practice as an effective and safe tuberculocidal agent.

Plants of the Asteraceae family are broadly used against microorganisms pathogenic to people and animals, although their potential has not been studied completely so far. In an in vitro experiment, we tested ethanolic, ethyl-ether, and dimethyl-sulfoxide extracts from the fruits, leaves, shoots, and roots of Xanthium strumarium L. for their effects on 13 species of bacteria and larvae of 3 species of nematodes. Over-8-mm-wide growth-inhibition zones of the colonies around disks saturated with ethanolic extracts from the fruits were observed for 11 bacteria: Enterobacter cloacae, Klebsiella pneumonia ssp. rhinoscleromatis, K. pneumonia ssp. ozaenae, K. aerogenes, Salmonella enterica, Escherichia coli, Morganella morganii, Enterococcus faecalis, E. faecium, Staphylococcus aureus, and Bacillus subtilis. Ethanol extract from the leaves inhibited growth of the colonies of 10 bacteria: E. cloacae, K. pneumonia ssp. rhinoscleromatis, K. pneumonia ssp. ozaenae, S. enterica, E. coli, Proteus vulgaris, E. faecalis, E. faecium, S. aureus, and B. subtilis. Ethanol extract from the stem inhibited growth of the colonies of only 6 bacteria: K. aerogenes, E. cloacae, P. vulgaris, E. faecium, S. aureus, and B. subtilis. Ethanol extract from the root inhibited growth of 10 bacteria: E. cloacae, K. pneumonia ssp. rhinoscleromatis, K. pneumonia ssp. ozaenae, K. aerogenes, S. enterica, E. coli, Pseudomonas aeruginosa, E. faecalis, E. faecium, and S. aureus. We analyzed the effects of extracts based on ethyl ether and dimethyl sulfoxide, finding no antiparasitic activity or expressed anthelmintic properties of various extracts from the fruits, leaves, stem, and roots of X. strumarium against larvae of the nematodes Strongyloides papillosus, Haemonchus contortus, and Muellerius capillaris.