Skip to main content

ORIGINAL RESEARCH article

Front. Vet. Sci.

Sec. Veterinary Pharmacology and Toxicology

Volume 12 - 2025 | doi: 10.3389/fvets.2025.1565787

This article is part of the Research Topic Natural Compounds in Veterinary Therapeutics View all 3 articles

Antibacterial and Antibiofilm Activity of Eucalyptus globulus Leaf Extract, Asiatic Acid and Ursolic Acid against Bacteria Isolated from Bovine Mastitis

Provisionally accepted
  • 1 Department of Veterinary Medical Sciences, University of Parma, Parma, Italy
  • 2 Department of Food and Drug Sciences, University of Parma, Parma, Emilia-Romagna, Italy
  • 3 Experimental Zooprophylactic Institute of Lombardy and Emilia Romagna (IZSLER), Brescia, Lombardy, Italy

The final, formatted version of the article will be published soon.

    Antibiotics represent the first line therapy for bovine mastitis. However, the increasing prevalence of multidrug-resistant organisms (MDROs) highlights the need for alternative therapeutic approaches. This study evaluated the antimicrobial and antibiofilm activities of Eucalyptus globulus leaf extract (EGL-L), ursolic acid (UA) and asiatic acid (AA) against Staphylococcus aureus (SA), Streptococcus uberis (SU), Streptococcus agalactiae (SAG), and Enterococcus spp. (EN) isolated from bovine mastitis, 39.7% of which were MDROs. The minimal inhibitory concentration (MIC) assay demonstrated that all the compounds exhibited antimicrobial activity against the tested bacteria, including MDROs. However, EGL-L was less effective (P<0.001) than UA or AA against field strains. UA was more effective against SAG and SU compared to SA (P<0.001), whereas AA was more effective against SU than SA (P<0.001). Conversely, EGL-L exhibited similar inhibitory effects on all bacteria. The biofilm-forming ability of the bacterial strains was also assessed, and the minimal biofilm inhibitory concentrations (MBICs) of the compounds were evaluated for moderate and strong biofilm producers. None of the compounds were able to completely inhibit biofilm formation. However, MBIC80 values within the tested concentration range were achieved for 15 out of 32 strains with EGL-L and for 27 out of 32 strains with UA and AA.These findings highlight a promising alternative to conventional antimicrobials for AA and UA, showing potential for topical intramammary use for the control and prevention of bovine mastitis, especially because of their efficacy against biofilm formation. Future research should focus on toxicity assessments and formulation development for potential topical administration.

    Keywords: Plant Extracts, Pentacyclic Triterpenes, Biofilm-producing organisms, Multidrugresistant organisms, MIC, Minimal biofilm inhibitory concentration

    Received: 23 Jan 2025; Accepted: 25 Mar 2025.

    Copyright: © 2025 Mezzasalma, Spadini, Spaggiari, Annunziato, Andreoli, Prosperi, Mochen, Cavirani, Grolli, Taddei, Costantino and Cabassi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Costanza Spadini, Department of Veterinary Medical Sciences, University of Parma, Parma, Italy

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

    Research integrity at Frontiers

    Man ultramarathon runner in the mountains he trains at sunset

    95% of researchers rate our articles as excellent or good

    Learn more about the work of our research integrity team to safeguard the quality of each article we publish.


    Find out more