How does HSA's antioxidant activity change under the influence of lincomycin and spectinomycin mixture? – A spectroscopic study

Lincomycin (LIN) belongs to the lincosamides group and is used in bacterial infections of soft tissues, the respiratory system, bone marrow, and bones, while spectinomycin (SPE) belongs to the group of aminoglycoside antibiotics and is used for the treatment of gonorrhoea. Both antibiotics are commonly used to treat humans separately while their mixture is used in veterinary preparations (SPE-LIN), and the combination of these antibiotics has not yet been used for human treatment. The aim of this study was to search for modulators of human serum albumin (HSA) antioxidant activity among antibacterial drugs, lincomycin (LIN) and spectinomycin (SPE). In order to study the effect of LIN and SPE on HSA antioxidant properties the DPPH and ABTS tests were used. UV-Vis spectrophotometry and circular dichroism (CD) spectroscopic techniques were used to find the cause of LIN and SPE modulatory activity related to HSA antiradical potential. Both LIN and SPE, as well as their mixture, did not show significant antioxidant activity, while in combination with HSA, they stimulated its antioxidant properties. CD measurements determined that the dominant secondary structure of HSA, regardless of the presence of ligands, was α-helix, and its percentage share slightly increased under the influence of LIN and SPE. The obtained results confirm the viability of further studies on the potential application of the combination of SPE-LIN in the treatment, not only in breeding animals. The proposed concept of research may be a response to the future needs in medicine. The assumed goal, which was the search for HSA modulators, has been achieved. • Studies of antibiotics interaction with proteins • Oxidative stress is an important factor in the pathogenesis of most diseases • The ligands influence on protein secondary and tertiary structure • The effect of ligand binding on protein antioxidant activity was investigated