Avian infectious bronchitis (IB) is a disease that can result in huge economic losses in the poultry industry. The high level of mutations of the IB virus (IBV) leads to the emergence of new serotypes and genotypes, and limits the efficacy of routine prevention. Medicinal plants, or substances derived from them, are being tested as options in the prevention of infectious diseases such as IB in many countries. The objective of this study was to investigate extracts of 15 selected medicinal plants for anti-IBV activity. Extracts of S. montana, O. vulgare, M. piperita, M. officinalis, T. vulgaris, H. officinalis, S. officinalis and D. canadense showed anti-IBV activity prior to and during infection, while S. montana showed activity prior to and after infection. M. piperita, O. vulgare and T. vulgaris extracts had > 60 SI. In further studies no virus plaques (plaque reduction rate 100%) or cytopathogenic effect (decrease of TCID50 from 2.0 to 5.0 log10) were detected after IBV treatment with extracts of M. piperita, D. canadense and T. vulgaris at concentrations of extracts ≥0.25 cytotoxic concentration (CC50) (P < 0.05). Both PFU number and TCID50 increased after the use of M. piperita, D. canadense, T. vulgaris and M. officinalis extracts, the concentrations of which were 0.125 CC50 and 0.25 CC50 (P < 0.05). Real-time PCR detected IBV RNA after treatment with all plant extracts using concentrations of 1:2 CC50, 1:4 CC50 and 1:8 CC50. Delta cycle threshold (Ct) values decreased significantly comparing Ct values of 1:2 CC50 and 1:8 CC50 dilutions (P < 0.05). Many extracts of plants acted against IBV prior to and during infection, but the most effective were those of M. piperita, T. vulgaris and D. canadense .

Viruses and bacteria can disrupt normal human functions; therefore, ways to use the beneficial properties of plants to promote health are constantly being researched. Plant materials that accumulate biologically active compounds can be used to create a new pharmaceutical form. This study aimed to investigate the biological activity of selected plant extracts and essential oil and to produce microcapsules. The main compounds in extracts and essential oil were determined using chromatographic methods, antioxidant activity was evaluated spectrophotometrically, antimicrobial activity was assessed by monitoring the growth of nine pathogens, and the antiviral effect on infected bird cells with coronavirus was evaluated. Trifolium pratense L. extract had the highest antioxidant (26.27 ± 0.31 and 638.55 ± 9.14 µg TE/g dw by the DPPH and ABTS methods, respectively) and antiviral activity (56 times decreased titre of virus). Liquorice extract expressed antibacterial activity against Gram-positive pathogens and the highest antioxidant activity using the FRAP method (675.71 ± 4.61 mg FS/g dw). Emulsion stability depended on excipients and their amount. Microcapsules with extracts and essential oil were 1.87 mm in diameter, and their diameter after swelling was increased more than two times in intestinal media, while less than 0.5 times in gastric media.

Bacteria are the primary microorganisms responsible for nosocomial infections. This study investigates the antibacterial, biofilm-disrupting, and cytotoxic properties of essential oils and their emulsions for the treatment of nosocomial pathogens. The antibacterial activity of selected essential oils and their emulsions was evaluated against clinically relevant strains, including Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa, and Salmonella Enteritidis. Among the tested compounds, cinnamaldehyde exhibited the most potent antibacterial activity, with minimum inhibitory concentrations ranging from 1.31 to 2.62 mg/mL against both Gram-positive and Gram-negative bacteria. Other essential oils, such as cinnamon, eucalyptus, and pine, also demonstrated antibacterial effects, although their efficacy against Pseudomonas aeruginosa was comparatively limited. In biofilm assays, cinnamaldehyde effectively disrupted biofilms formed by S. aureus, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa, indicating its potential for treating biofilm-associated infections. Cytotoxicity testing revealed that while cinnamon essential oil and cinnamaldehyde exhibited cytotoxic effects at concentrations above 0.1%, other essential oils such as basil and eucalyptus were non-toxic at the tested concentrations. These findings suggest that cinnamaldehyde is a promising agent for managing nosocomial infections, combining effective antibacterial and biofilm-disrupting properties with acceptable safety for non-target cells at appropriate doses.

Increasing antimicrobial resistance among Gram-positive pathogens and pathogenic fungi remains one of the major public healthcare threats. Therefore, novel antimicrobial candidates and scaffolds are critically needed to overcome resistance in Gram-positive pathogens and drug-resistant fungal pathogens. In this study, we explored 1-(2-hydroxyphenyl)-5-oxopyrrolidine-3-carboxylic acid and its 3,5-dichloro-2-hydroxyphenyl analogue for their in vitro antimicrobial activity against multidrug-resistant pathogens. The compounds showed structure-dependent antimicrobial activity against Gram-positive pathogens (S. aureus, E. faecalis, C. difficile). Compounds 14 and 24b showed promising activity against vancomycin-intermediate S. aureus strains, and favorable cytotoxic profiles in HSAEC-1 cells, making them attractive scaffolds for further development. 5-Fluorobenzimidazole, having a 3,5-dichloro-2-hydroxyphenyl substituent, was found to be four-fold, and hydrazone, with a thien-2-yl fragment, was two-fold stronger than clindamycin against methicillin resistant S. aureus TCH 1516. Moreover, hydrazone, bearing a 5-nitrothien-2-yl moiety, showed promising activity against three tested multidrug-resistant C. auris isolates representing major genetic lineages (MIC 16 µg/mL) and azole-resistant A. fumigatus strains harboring TR34/L98H mutations in the CYP51A gene. The anticancer activity characterization demonstrated that the 5-fluorobenzimidazole derivative with a 3,5-dichloro-2-hydroxyphenyl substituent showed the highest anticancer activity in an A549 human pulmonary cancer cell culture model. Collectively these results demonstrate that 1-(2-hydroxyphenyl)-5-oxopyrrolidine-3-carboxylic acid derivatives could be further explored for the development of novel candidates targeting Gram-positive pathogens and drug-resistant fungi.

In the present study, new series of benzoxazolin-2-one linked to a variety of hydrazones and azoles were synthesized and assessed for their antibacterial properties against different bacterial microorganisms. All the synthesized target compounds were characterized by ¹H NMR, ¹³C NMR and IR spectroscopy, and elemental analysis as well. The antibacterial activity of the synthesized compounds was evaluated according to the bacteriostatic and bactericidal activity against the tested pathogen strains by determining the minimum inhibition (MIC) and minimum bactericidal (MBC) concentrations and MBC/MIC ratios. The MIC was evaluated by the broth dilution and the MBC was evaluated by plating methods. The in vitro analysis suggested that some compounds, namely, amide, 5-chlorobenzimidazole, hydrazones with a 3-chloro substitution on the additional phenyl ring, and hydrazones with 2-furyl and 5-nitro-2-furyl substituents, demonstrated wide antibacterial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Salmonella Enteritidis. The most sensitive strains appeared to be Gram-negative E. coli and Gram-positive B. subtilis, while S. aureus showed some resistance. The most resistant pathogen was found to be S. enteritidis. The remaining compounds demonstrated moderate to low antibacterial potential. The research results have shown that benzoxazolinone-based derivatives are suitable for the development of a library of compounds and can be used in the future development of antibacterial drugs against various Gram-positive and Gram-negative pathogens, which is of great importance in therapy practice.

The aim of the present study was to detect canine parvovirus (CPV) from faecal samples of clinically ill domestic dogs by polymerase chain reaction (PCR) followed by VP2 gene partial sequencing and molecular characterization of circulating strains in Lithuania. Eleven clinically and antigen-tested positive dog faecal samples, collected during the period of 2014-2015, were investigated by using PCR. The phylogenetic investigations indicated that the Lithuanian CPV VP2 partial sequences (3025-3706 cds) were closely related and showed 99.0-99.9% identity. All Lithuanian sequences were associated with one phylogroup, but grouped in different clusters. Ten of investigated Lithuanian CPV VP2 sequences were closely associated with CPV 2a antigenic variant (99.4% nt identity). Five CPV VP2 sequences from Lithuania were related to CPV-2a, but were rather divergent (6.8 nt differences). Only one CPV VP2 sequence from Lithuania was associated (99.3% nt identity) with CPV-2b VP2 sequences from France, Italy, USA and Korea. The four of eleven investigated Lithuanian dogs with CPV infection symptoms were vaccinated with CPV-2 vaccine, but their VP2 sequences were phylogenetically distantly associated with CPV vaccine strains VP2 sequences (11.5-15.8 nt differences). Ten Lithuanian CPV VP2 sequences had monophyletic relations among the close geographically associated samples, but five of them were rather divergent (1.0% less sequence similarity). The one Lithuanian CPV VP2 sequence was closely related with CPV-2b antigenic variant. All the Lithuanian CPV VP2 partial sequences were conservative and phylogenetically low associated with most commonly used CPV vaccine strains.