Modification of some biochemical parameters of bacterial cultures under the influence of chemical compounds and spirulina extracts

Abstract

Introduction In microbial systems, exposure to oxidative stress can lead to significant alterations in cellular homeostasis, affecting membrane integrity, enzymatic activity, and overall metabolic function. The evaluation of biochemical parameters such as lipid peroxidation, protein oxidation, and antioxidant enzyme levels (e.g., catalase, superoxide dismutase) provides critical insights into the cellular responses to both harmful and protective agents. Among natural compounds with recognized bioactive potential, Spirulina platensis stands out due to its high content of phycocyanin, phenolic compounds, and other antioxidants, which have demonstrated the capacity to modulate oxidative stress in various biological models. Furthermore, the combined or comparative study of Spirulina extracts and synthetic chemical compounds can elucidate potential synergistic or antagonistic effects on bacterial cultures, contributing to a better understanding of cellular defense mechanisms and the potential development of new antimicrobial or protective strategies. Aim of study: establishing the specific mechanisms of action of antimicrobial compounds is essential both for evaluating their therapeutic effects and for promoting the pharmaceutical product from concept to its implementation in clinical practice. Material and methods A comprehensive study was conducted, which included three newly synthesized chemical compounds and two spirulina extracts as the study object. To study the change in biochemical parameters under the influence of these compounds, three microbial strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923) were used. All experimental results obtained were subjected to the usual statistical analysis with the application of descriptive statistics and inferential statistics tools. Rezults Spirulina extracts did not exhibit direct toxic effects on the tested bacterial strains, as indicated by the unchanged levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH) compared to control samples. In contrast, the chemical compounds, when applied at their minimum inhibitory concentrations (MICs), induced marked toxic effects in the bacterial cultures: increased MDA concentration, elevated LDH activity, and decreased activity of key antioxidant enzymes. Notably, the combined application of Spirulina extracts and chemical compounds proved to be more effective, enabling a 2- to 4-fold reduction in the MICs required to achieve similar biochemical effects. Conclusions Spirulina extracts demonstrated no toxic effects on the investigated bacterial strains, in contrast to the synthetic chemical compounds, which exerted significant toxicity even at minimal inhibitory concentrations. The combination of chemical and biological compounds revealed a synergistic effect, allowing for lower effective doses and enhanced biochemical impact.