In vitro Antimicrobial Activity Profile of Modified Pyrimidine Nucleosides Derivatives

Abstract

Background: The increase in prevalence of antimicrobial-resistant bacteria (ARB) is currently a serious threat, thus there is a need for new classes antimicrobial compounds to combat infections caused by these ARB. The growth inhibition ability of derivatives of the components of nucleic acids has been well-characterized but not for its antimicrobial characteristics.
 Aims: To evaluate in vitro antimicrobial activity profile of modified pyrimidine nucleosides derivatives.
 Methodology: Modified nucleosides arabinofuranosylcytosine (cytarabine, ara-C), [1-(2',3',5'-tri-O-acetyl-β-D-ribofuranosyl)-4-(1,2,4-triazol-1-yl)]uracil (TTU), and nucleotides cytarabine-5′-monophosphate (ara-CMP), and O2,2′-cyclocytidine-5′-monophosphate (cyclocytidine monophosphate, cyclo-CMP) were synthetized and subsequentially checked for antibacterial activity. Bacterial cells characteristics were assessed by antiproliferative and the production of intracellular reactive oxygen species (ROS) assays.
 Results: It was found that modified nucleosides ara-C, and TTU, and nucleotides ara-CMP, and cyclo-CMP were able to inhibit Escherichia coli, Sarcina lutea, Bacillus cereus, and Proteus mirabilis strains in a time and dose dependent manner via killing kinetics assay. Gram-negative (E. coli and P. mirabilis) bacteria stains were more sensitive to the exposure of TTU and cyclo-CMP and less sensitive to the exposure of ara-C and ara-CMP compared to gram-positive ones. The most effective cells growth inhibitor for gram-positive strains (S. lutea, B. cereus) was ara-CMP with ED50 = 5.2•10-5 M and 3.1•10-4 M, respectively. Sarcina lutea appeared to be the most sensitive bacteria strain to the exposure of all studied compounds. It was demonstrated that studied modified pyrimidine nucleosides derivatives enhanced the production of intracellular ROS over time (validated via DCFA-DA probe assay).
 Conclusion: This study has revealed the mechanism of action of cytarabine, cyclocytidine monophosphate, and TTU as an antimicrobial agent for the first time, and has shown that these pyrimidine derivatives enhanced might be able to combat infections caused by Escherichia coli, Sarcina lutea, Bacillus cereus, and Proteus mirabilis in the future.

Analysis of the antibacterial efficacy of modified purines derivatives

“…Infectious diseases may be said to be making a come-returned, due to chronic below-funding in anti-infective drug improvement, decreased attractiveness of vaccines, and the growing spread and severity of drug resistance [12,13]. Most antibacterial, antifungal, and antiparasitic pills are decades vintage, and the ongoing loss of development threatens the treatability of many infectious sicknesses.…”

“…The production of ROS by bacterial strains after treatment with modified nucleosides/nucletides was evaluated using indicator 2′-7′dichlorodihydrofluorescein diacetate (DCFH-DA) (Sigma-Aldrich, UK), which can detect a broad range of ROS including nitric oxide and hydrogen peroxide [12]. The adjusted bacterial culture (0.5 McFarland exponential phase bacteria culture) were treated with different concentrations of studied compounds in presence of DCFH-DA at a final concentration of 5 µM in 0.85% saline and incubated at 37 °C aerobically for 24 h. Untreated bacterial culture was served as a negative control.…”

Study the effect of antioxidants and ROS levels on antibacterial activity of some of modified pyrimidine derivatives

“…Due to chronic underfunding in anti-infective medication improvement, declining appeal of vaccines, and the increased prevalence and severity of treatment resistance, infectious illnesses may be said to be making a comeback [12,13] . The majority of antibacterial, antifungal, and antiparasitic medications are decades old, and the continued decline in research and development jeopardizes the capacity to treat numerous infectious diseases.…”

“…Utilizing the marker 2′-7′-dichlorodihydrofluorescein diacetate (DCFH-DA) (Sigma-Aldrich, UK), which can identify a variety of ROS including nitric oxide and hydrogen peroxide, after being exposed to altered nucleosides and nucleotides, it was examined whether or not certain bacterial strains produced ROS [12] . In the presence of DCFH-DA at a final concentration of 5 M in 0.85 percent saline, the modified bacterial culture (0.5 percent McFarland exponential phase bacteria culture) was exposed to various concentrations of the examined compounds and incubated at 37 °C aerobically for 24 hours.…”