Antibacterial activity against bovine mastitis-inducing pathogens and antiradical activity of polyphenolic-compounds-containing plant extracts. Summary of the Doctoral Thesis
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Date
2025
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Rīga Stradiņš University
Abstract
Bovine mastitis is an infectious disease of the cow’s udder, which is usually treated with antibiotics. The overuse and misuse of antibiotics has led to the widespread development of bacterial resistance. Restrictions on the use of antibiotics create a need for alternative treatments and prophylactic measures to reduce the incidence and spread of mastitis. Antioxidant properties of plants – ability to scavenge free radicals, help animals recover and heal faster. Herbal medicine has been used traditionally by farmers for centuries to treat infectious and chronic diseases. However, there is little scientific evidence on the veterinary use of plant extracts. The Thesis aims to provide information on the use of plant extracts against bovine mastitis pathogens, their antiradical activity and to characterise their polyphenolic content. The dried plant material was extracted with 30 %, 50 %, 70 % ethanol and acetone and then freeze-dried for further analysis. The total phenolic, flavonoid, and tannin contents were determined by spectroscopic methods. Fourier transform infrared spectroscopy and high-performance liquid chromatography were used to characterise the chemical composition of the extracts. Clinical isolates inducing bovine mastitis (Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus) and reference cultures of S. aureus and E. coli were used for antibacterial tests. All extracts were screened for their antibacterial activity using a disc diffusion test, and the minimum inhibitory concentration and the minimum bactericidal concentration were determined for the most effective extracts. The antiradical activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The type of solvent affected the amount of phenolics extracted and the pharmacological effects of the extracts. The plants contained comparable amounts of tannins, which are not often reported in studies but have pharmacological activities. The acetone extracts had a higher total phenolic content and a higher total flavonoid content. All the plant extracts analysed were effective against S. aureus, but the effect against other bovine mastitis pathogens varied by the type of extract used. The types of phenolic compounds present in these plant extracts have a significant impact on the antioxidant activity. The bark of Q. robur and the herbs of C. vulgaris, and the flower and leaf of T. vulgare had good antioxidant and antibacterial potential. Plant extracts have promising pharmacological effects in vitro for the development of a product for bovine mastitis.
Description
The Doctoral Thesis was developed at Rīga Stradiņš University, Latvia. Defence: at the public session of the Promotion Council of Basic Medicine on 4 April 2025 at 12.00 in the Hippocrates Lecture Theatre, 16 Dzirciema Street, Rīga Stradiņš University and remotely via online platform Zoom.
Keywords
Summary of the Doctoral Thesis, antibacterial, antioxidant, bovine mastitis, herbal medicine, polyphenols, tannins
Citation
Teterovska (Šukele), R. 2025. Antibacterial activity against bovine mastitis-inducing pathogens and antiradical activity of polyphenolic-compounds-containing plant extracts: Summary of the Doctoral Thesis: Sub-Sector – Pharmacognosy. Rīga: Rīga Stradiņš University. https://doi.org/10.25143/prom-rsu_2025-04_dts