The antimicrobial activity and toxicity of three novel synthetic antibacterial agents containing tris(1H-indol-3-yl)methylium fragment were studied in vitro and in vivo. All compounds in vitro revealed high activity (minimal inhibitory concentration (MIC) 0.13–1.0 µg/mL) against bacteria that were either sensitive or resistant to antibiotics, including multidrug-resistant clinical isolates. The derivatives combining high antimicrobial activity with relatively low cytotoxicity against human donor fibroblasts HPF-hTERT were subjected to further testing on mice. In vivo they revealed fairly good tolerance and relatively low toxicity. Acute toxicity was evaluated, and the main indicators of toxicity, including LD₅₀ and LD₁₀, were determined. A study of compounds in vivo showed their efficiency in the model of staphylococcal sepsis in mice. The efficiency of compounds may be due to the ability of indolylmethylium salts to form pores in the cytoplasmic membrane of microbial cells and thereby facilitate the penetration of molecules into the pathogen.

Glycopeptide antibiotics are still in demand in clinical practice for treating infections caused by resistant gram-positive pathogens; however, their use is limited due to severe adverse reactions. Their predominant types of side effects are immunoglobulin E-mediated or nonmediated hypersensitivity reactions. Therefore, the development of new glycopeptide antibiotics with improved toxicity profiles remains an important objective in advancing modern antimicrobial agents. We investigated a new eremomycin aminoalkylamide flavancin, its anaphylactogenic properties, influence on histamine levels in blood plasma, pseudoallergic inflammatory reaction on concanavalin A and the change in the amount of flavancin in the blood plasma after administration. It has been shown that flavancin does not demonstrate anaphylactogenic properties. The injection of flavancin resulted in a level of histamine in the blood three times lower than that caused by vancomycin. The therapeutic dose of vancomycin led to a statistically significant increase in the concanavalin A response index compared to flavancin (54% versus 3.7%). Thus, flavancin does not cause a pseudo-allergic reaction. The rapid decrease in flavancin concentration in the blood and the low levels of histamine in the plasma lead us to assume that any pseudoallergic reactions resulting from flavancin application, if they do occur in clinical practice, will be significantly less compared to the use of vancomycin.

Glycopeptide antibiotics have side effects that limit their clinical use. In view of this, the development of glycopeptides with improved chemotherapeutic properties remains the main direction in the search for new antibacterial drugs. The objective of this study was to evaluate the toxicological characteristics of new semi-synthetic glycopeptide flavancin. Acute and chronic toxicity of antibiotic was evaluated in Wistar rats. The medium lethal dose (LD₅₀) and the maximum tolerated doses (MTD) were calculated by the method of Litchfield and Wilcoxon. In the chronic toxicity study, the treatment regimen consisted of 15 daily intraperitoneal injections using two dosage levels: 6 and 10 mg/kg/day. Total doses were equivalent to MTD or LD₅₀ of flavancin, respectively. The study included assessment of the body weight, hematological parameters, blood biochemical parameters, urinalysis, and pathomorphological evaluation of the internal organs. The results of the study demonstrated that no clinical-laboratory signs of toxicity were found after 15 daily injections of flavancin at a total dose close to the MTD or LD₅₀. The pathomorphological study did not reveal any lesions on the organ structure of animals after low-dose administration of flavancin. Thus, flavancin favorably differs in terms of toxicological properties from the glycopeptides currently used in the clinic.

Introduction. Antibiotics of aureolic acid group are highly effective anticancer drugs. New data about their mode of action caused the need for creation of analogs with improved pharmacological properties. The methods of selective chemical modification of aureolic acid antibiotic olivomycin A were developed at the Gause Institute of New Antibiotics. Some semisynthetic derivatives have been prepared. The most active compound – N, N-dimethylaminoethylamide 1’-des-(2,3-dihydroxybutteroil)-1’-carboxy-olivomycin A (olivamide) – was selected for advanced preclinical testing.Objective. The aim of the study was to investigate the toxicological safety of olivamide drug formulation in chronic experiment on rabbits.Materials and methods. The study was performed in male and female “Soviet chinchilla” rabbits. Drug formulation was administrated intravenously at the total doses of maximum tolerated dose and 50 % lethal dose (15 × 0.02 mg/kg or 15 × 0.04 mg/kg with 24-h inter val). During the experiment body weight, hematological parameters, blood biochemical parameters, electrocardiography and urinalysis were performed. Animals were sacrificed 1 and 30 days post treatment. The internal organs were subjected to histological evaluation.Results. It has been shown that the treatment with total dose of olivamide maximum tolerated dose produces an increase of aspartate aminotransferase, urea and creatinine level in serum. Urinalysis revealed the elevation of protein, urobilinogen and urine specific grav ity. Administration of high dose of olivamide in addition to the above-mentioned laboratory parameter caused the raising of alkaline phosphatase and total bilirubin level in serum. Microscopic pathology observation showed structure abnormalities of varying severity in liver and kidneys.Conclusion. Olivamide drug formulation displayed dose-dependent toxic properties. Multiple administration of low dose of the drug produces transient toxic effects completely reversible within 30 days.

A new antitumor multi-target drug anthrafuran, with cellular targets such as topoisomerase I/II and some protein kinases, was obtained in Gause Institute of New Antibiotics and was demonstrated to have a reliable specific effect on different murine and human tumor models by oral administration. In this study, we focused on the evaluation of subchronic toxicity of oral anthrafuran drug formulation (AF) on Chinchilla rabbits. The absence of any changes in the condition or behavior of animals was shown for oral anthrafuran. Changes with reversible and dose-dependent hepato- and nephrotoxicity at low doses, as well as hemato- and gastrointestinal toxicity at high doses, were confirmed pathomorphologically. The identified toxic properties are extremely valuable, since oral anthrafuran does not have the limiting cardio- and myelotoxicity. Anthrafuran with 2 mg/kg/day or 6 mg/kg/day doses was administrated orally over 15 days. Investigations include assessment of the body weight, hematological and serum biochemical parameters and urinalysis, electrocardiography and pathomorphological evaluation of the internal organs. Quantitative data were processed statistically with Student’s t-Test, p < 0.05. Revealed during the subchronic study were the favorable toxicological properties of oral anthrafuran as opposed to clinical anthracyclines, oral idarubicin, or parenteral doxorubicin, which allows it to be considered promising for further research.

Introduction . Currently, the study of the neurotoxic properties of new drugs is an indispensable step towards the promotion of the medicine to clinical practice. The original antitumor drug anthrafuran (LCTA-2034), obtained in Gause Institute of New Antibiotics, has demonstrated high activity against transplantable mice tumors. Previous studies have shown that the drug in high doses causes brain tissues damage.Objective: a pilot investigation of anthrafuran neurotoxicity.Materials and methods . The study was carried out on 52 female outbred rats. The suspension of drug in water for injection was administrated per os at a single maximum tolerated dose of 170 mg/kg. The testing was performed on “open field” setting 1, 4 and 8 h and repeated on day 1 and 30 post treatment.Results . It was found that the administration of the drug reduced both motor (covered distance, average speed) and research (the number of rearings, contacts with the “burrow”) activity as compared to control. These effects were manifested to the greatest extent 4 h post treatment. A day later, when rats re-visit “open field”, the parameters under study increased in this group, while in the control group these indicators decreased.Conclusion . Anthrafuran exhibits a reversible inhibitory effect on the motor and research activity of rats.