Derivatives of 1,2,4-triazole-3-thione exhibit a variety of biological activities, including antimicrobial (e.g., compounds 31d–k, 32d, 36f), antitumor (e.g., 71, 77a–c, 82g, 94h), anti-inflammatory, analgesic (100a, 102, 105), antidiabetic, and antioxidant (104, 138) activity. These compounds can be efficiently synthesized by classical methods (e.g., cyclization of thiosemicarbazides) and/or modern “green” approaches, which allow for obtaining target compounds in high yields (up to 96%). The presence of electron-donating groups (e.g., -OH, -OCH₃) enhances antimicrobial and antitumor activity. Substituents in the aromatic ring (e.g., NO₂, Cl) affect the ability to bind to biological targets such as DNA or enzymes. 1,2,4-triazole-3-thiones can also be used as fungicides and herbicides (e.g., 131), demonstrating high efficiency against phytopathogens. Thus, 1,2,4-triazole-3-thione derivatives are multifunctional compounds with high potential for the development of new drugs and agrochemicals. Their further study and modification can lead to the creation of more effective and safer drugs.

1,2,4-Triazole derivatives have a wide range of biological activities. The most well-known drug that contains 1,2,4-triazole as part of its structure is the nucleoside analogue ribavirin, an antiviral drug. Finding new nucleosides based on 1,2,4-triazole is a topical task. The aim of this study was to synthesize ribosides and deoxyribosides of 1,2,4-triazole-3-thione derivatives and test their antiviral activity against herpes simplex viruses. Three compounds from a series of synthesized mono- and disubstituted 1,2,4-triazole-3-thione derivatives were found to be substrates for E. coli purine nucleoside phosphorylase. Of six prepared nucleosides, the riboside and deoxyriboside of 3-phenacylthio-1,2,4-triazole were obtained at good yields. The yields of the disubstituted 1,2,4-triazol-3-thiones were low due to the effect of bulky substituents at the C3 and C5 positions on the selectivity of enzymatic glycosylation for one particular nitrogen atom in the triazole ring. The results of cytotoxic and antiviral studies on acyclovir-sensitive wild-type strain HSV-1/L2(TK+) and acyclovir-resistant strain (HSV-1/L2/R^ACV) in Vero E6 cell culture showed that the incorporation of a thiobutyl substituent into the C5 position of 3-phenyl-1,2,4-triazole results in a significant increase in the cytotoxicity of the base and antiviral activity. The highest antiviral activity was observed in the 3-phenacylthio-1-(β-D-ribofuranosyl)-1,2,4-triazole and 5-butylthio-1-(2-deoxy-β-D-ribofuranosyl)-3-phenyl-1,2,4-triazole nucleosides, with their selectivity indexes being significantly higher than that of ribavirin. It was also found that with the increasing lipophilicity of the nucleosides, the activity and toxicity of the tested compounds increased.

The paper was dedicated to the investigation of the insecticidal activities of recently prepared 1,3,4-oxadiazole compounds and their in vitro efficacy was determined with the help of cell lines taken out of Helicoverpa zea, Trichoplusia ni and Lymantria dispar. The MTT assay yielded results that showed that the compounds synthesized had insecticidal activities between 88.4 -97.2 - 100 µM that were similar to those of the commercial insecticide Imidacloprid 2F of 96.4 -98.3 - 100 µM. In silico testing showed that the newly prepared compounds bind to a variety of amino acid residues either with several interaction modes at the same time such as π-π stacking, hydrogen bonding, π-π anion interaction, and π-π alkyl interaction, specifically against acetylcholinesterase (AChE) of the insect species used. Since they are relatively harmless to the environment, these 1,3,4-oxadiazole derivatives have a potential as alternative agents in sustainable pests control in agriculture, which could be beneficial compared to the use of conventional insecticides. The results highlight the effectiveness of such compounds as effective agents against insect cell lines in agriculture. However, in order to completely prove their practical implementation, there is a need to conduct additional in vivo research and field tests are suggested to verify their effectiveness in real-world situations.

Background: SARS-CoV-2 is a virus responsible for the COVID-19 pandemic that began in late 2019. This pandemic has had a devastating impact worldwide, resulting in over 6.95 million deaths. The development of effective vaccines against the virus is crucial for preventing infection and reducing the severity of the disease. Objective: This study aimed to obtain the recombinant receptor-binding domain (RBD) and the nucleocapsid (N) proteins of SARS-CoV-2 as well as assess the immunogenicity of the combination of these recombinant proteins. Methods: The recombinant plasmids encoding the receptor-binding domain (RBD) of the spike protein of the Omicron variant and the nucleocapsid protein of SARS-CoV-2 were cloned into the yeast Pichia pastoris. The optimal fermentation conditions were established for recombinant P. pastoris strains. The methods for the isolation and purification of the target recombinant RBD and nucleocapsid proteins were developed. The immunogenicity of the purified recombinant proteins was evaluated by injecting them into mice and analyzing the specific IgG antibody responses using ELISA. Results: The study found that RBD and N proteins, as well as their combination, showed antigenic specificity and were highly immunogenic in mice. The immunogenicity was measured by determining the antibody titer, which represents the concentration of antibodies produced in response to the antigen. The antibody titers were 1:60000 for both RBD and N proteins, and 1:80000 for their combination. Conclusion: These findings suggest that the expressed proteins could be potential candidates for the development of vaccines or immunological diagnostic test kits for combatting or detecting the Omicron variant of SARS-CoV-2.