In Vitro Antibacterial Activity and Chemical Characterization of a Laboratory-Prepared Thymus vulgaris L. Absolute against Clinical Bacterial Isolates Including Multidrug-Resistant Strains
DOI:
https://doi.org/10.54361/LJMR.20.2.86Keywords:
Thymus vulgaris, absolute, thymol, carvacrol, antibacterial activity, GC-MS, MIC, MBC, multidrug resistance, clinical isolatesAbstract
Background: Healthcare-associated infections are a major challenge, especially with the rise of antimicrobial-resistant and multidrug-resistant (MDR) pathogens. Plant-derived preparations, particularly absolutes obtained via solvent extraction, offer a promising alternative to conventional antibiotics and differ chemically from essential oils.Objective: This study aimed to prepare an absolute from Thymus vulgaris L. using low-temperature solvent extraction, characterize its chemical composition via GC-MS, and evaluate its antibacterial activity against clinical bacterial isolates, including MDR strains, by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Materials and Methods: Aerial parts of T. vulgaris were collected from Al-Jabal Al-Akhdar, Libya. The dried plant material was extracted with n-hexane at 35°C, followed by ethanol treatment to remove waxes. Antibacterial activity was evaluated using the disc diffusion method against 202 selected isolates. MIC and MBC were determined by broth microdilution, and the chemical composition was analyzed by GC-MS. Results: The absolute yield was 1.92 ± 0.12% (w/w), compared to 0.85 ± 0.08% for the steam-distilled oil. GC-MS identified 35 compounds, with thymol (42.5 ± 1.8%) and carvacrol (28.3 ± 1.5%) as the major constituents. The absolute exhibited concentration-dependent activity, with inhibition zones ranging from 6.2 to 34.1 mm. MIC values ranged from 1.25 to 10 µL/mL, while MBC values ranged from 2.5 to 20 µL/mL, with an MBC/MIC ratio ≤4. Conclusion: The T. vulgaris absolute demonstrated significant in-vitro antibacterial activity against clinical isolates, including MRSA and ESBL-producing strains. However, further studies on cytotoxicity, stability, and in-vivo efficacy are required before any therapeutic application can be considered.
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References
1. Allegranzi B, Bagheri Nejad S, Combescure C, Graafmans W, Attar H, Donaldson L, et al. Burden of endemic health-care-associated infection in developing countries: systematic review and meta-analysis. Lancet. 2011;377:228-241.
2. Prestinaci F, Pezzotti P, Pantosti A. Antimicrobial resistance: a global multifaceted phenomenon. Pathog Glob Health. 2015;109:309-318.
3. Tongnuanchan P, Benjakul S. Essential oils: extraction, bioactivities, and their uses for food preservation. J Food Sci. 2014;79:R1231-R1249.
4. D'Auria M. Essential oils and their extraction: a review. In: Studies of Aromatic Plants and Essential Oils. The distinction between distilled oils and solvent-derived absolutes should be considered when interpreting biological activity. Chem Eng Trans. 2020;79:355-360.
5. Chouhan S, Sharma K, Guleria S. Antimicrobial activity of some essential oils—present status and future perspectives. Medicines (Basel). 2017;4:58.
6. Burt S. Essential oils: their antibacterial properties and potential applications in foods—a review. Int J Food Microbiol. 2004;94:223-253.
7. Sienkiewicz M, Łysakowska M, Pastuszka M, Bienias W, Kowalczyk E. The potential of use basil and rosemary essential oils as effective antibacterial agents. Microb Drug Resist. 2012;18:137-148.
8. Stahl-Biskup E. Essential oil chemistry of the genus Thymus—a global view. In: Stahl-Biskup E, Sáez F, editors. Thyme: The Genus Thymus. London: Taylor & Francis; 2002. p. 75-124.
9. Thompson JD, Chalchat JC, Michet A, Linhart YB, Ehlers B. Qualitative and quantitative variation in monoterpene co-occurrence and composition in the essential oil of Thymus vulgaris chemotypes. J Chem Ecol. 2003;29:859-880.
10. Xu J, Zhou F, Ji BP, Pei RS, Xu N. The antibacterial mechanism of carvacrol and thymol against Escherichia coli. Lett Appl Microbiol. 2008;47:174-179.
11. Nazzaro F, Fratianni F, De Martino L, Coppola R, De Feo V. Effect of essential oils on pathogenic bacteria. Pharmaceuticals (Basel). 2013;6:1451-1474.
12. Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing. 34th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2024.
13. Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect. 2012;18:268-281.
14. Trombetta D, Castelli F, Sarpietro MG, Venuti V, Cristani M, Daniele C, et al. Mechanisms of antibacterial action of three monoterpenes. Antimicrob Agents Chemother. 2005;49:2474-2478.
15. Ultee A, Bennik MH, Moezelaar R. The phenolic hydroxyl group of carvacrol is essential for action against the food-borne pathogen Bacillus cereus. Appl Environ Microbiol. 2002;68:1561-1568.
16. Hyldgaard M, Mygind T, Meyer RL. Essential oils in food preservation: mode of action, synergies, and interactions with food matrix components. Front Microbiol. 2012;3:12.
17. Nikaido H. Molecular basis of bacterial outer membrane permeability revisited. Microbiol Mol Biol Rev. 2003;67:593-656.
18. Poole K. Efflux-mediated multiresistance in Gram-negative bacteria. Clin Microbiol Infect. 2004;10:12-26.
19. Levison ME, Levison JH. Pharmacokinetics and pharmacodynamics of antibacterial agents. Infect Dis Clin North Am. 2009;23:791-815.
20. Hazzit M, Baaliouamer A, Veríssimo CJ, Faleiro ML, Miguel MG. Chemical composition and biological activities of Algerian Thymus oils. Food Chem. 2009;116:714-720.
21. Sienkiewicz M, Poznańska-Kurowska K, Kaszuba K, Kowalczyk E. The antibacterial activity of thyme essential oil against clinical bacterial isolates. Med Chem. 2011;7:782-786.
22. Centers for Disease Control and Prevention. Antibiotic Resistance Threats in the United States. Atlanta, GA: CDC; 2019.
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