Evaluation of the Inhibitory Activity of Aqueous and Ethanolic Extracts of Tilia cordata Against Antibiotic-Resistant Escherichia coli Strains Isolated from Urinary Tract Infections
Keywords:
Tilia cordata, Escherichia coli, urinary tract infections, antibiotic resistance, aqueous extract, ethanolic extract, minimum inhibitory concentration, phytochemical screeningAbstract
The rapid emergence of multidrug-resistant Escherichia coli (MDR E. coli) in urinary tract infections (UTIs) has necessitated the search for alternative therapeutic agents derived from natural plants. This study aimed to evaluate the inhibitory activity of aqueous and ethanolic extracts of Tilia cordata (linden) against clinical isolates of antibiotic-resistant E. coli obtained from UTIs. A total of 30 clinical isolates were collected from urine samples of patients diagnosed with UTIs. Antibiotic susceptibility testing was performed using the disk diffusion method against commonly used antibiotics including ampicillin, gentamicin, ciprofloxacin, ceftriaxone, and imipenem. The minimum inhibitory concentrations (MICs) of T. cordata aqueous and ethanolic extracts were determined using the broth microdilution method, while the minimum bactericidal concentrations (MBCs) were assessed via subculturing on Mueller-Hinton agar. Phytochemical screening of both extracts was conducted using standard qualitative methods. Results revealed that 86.7% (26/30) of isolates were resistant to at least three antibiotic classes, classified as MDR. The ethanolic extract exhibited superior antibacterial activity compared to the aqueous extract, with MIC values ranging from 3.125 to 12.5 mg/mL, while the aqueous extract showed MICs between 6.25 and 25 mg/mL. The MBC/MIC ratio indicated a bactericidal effect for the ethanolic extract against 73% of tested isolates. Phytochemical analysis revealed the presence of tannins, flavonoids, saponins, and phenolic compounds in both extracts, with higher concentrations in the ethanolic extract. These findings suggest that T. cordata ethanolic extract possesses significant inhibitory activity against MDR E. coli isolates, supporting its potential as a natural alternative or adjunctive therapy for UTIs. Further in vivo studies and toxicity assessments are recommended.
References
[1] Alshawish, F. M. B. M., Abdala, B. A. F., Arqeeq, M. A. M., & Salem, M. O. A. (2025). Phytochemical Profiling screening and Evaluation of Their Multi-target Biological Potentials of Catha edulis Ethanolic Extract. Al-Imad Journal of Humanities and Applied Sciences (AJHAS), 47-53.
[2] Ben Hsin, M. A. M., Emsaed, H. A. M., Abujarida, A. R., Sauf, M. A., Soof, S. A., & Salem, M. O. A. (2025). A Study on the Isolation and Identification of Bacteria in Patients with Urinary Tract Infections in Libyan Laboratories. Afro-Asian Journal of Scientific Research (AAJSR), 1(4), 1-10.
[3] Clinical and Laboratory Standards Institute. (2024). Performance Standards for Antimicrobial Susceptibility Testing (34th ed.). CLSI supplement M100. CLSI.
[4] Kadak, A. E., & Salem, M. O. A. (2020). Antibacterial Activity of Chitosan, Some Plant Seed Extracts and Oils Against Escherichia coli and Staphylococcus aureus. Alinteri Journal of Agriculture Sciences, 35(2), 144-150. doi: 10.47059/alinteri/V35I2/AJAS20086
[5] Khalil, R. A. A., Salem, I. A. S., & Salem, M. O. A. (2025). A Biochemical Study on the Effect of Alcoholic and Aqueous Extracts of Plantago ovata Leaves in Inhibiting the Growth of Antibiotic-Resistant Bacteria. Al-Imad Journal of Humanities and Applied Sciences (AJHAS), 1(2), 38-46.
[6] Salem, M. O. A. (2024). Antimicrobial Activity of Aqueous Methanolic Extract of Lichen (Usnea barbata) Against Escherichia coli and Staphylococcus aureus. Libyan Journal of Ecological & Environmental Sciences and Technology, 6(01), 19-23.
[7] Salem, M. O. A., & Alhadad, A. A. (2026). Phytochemical Profiling and In Vitro Antimicrobial Potential of Hypericum decaisneanum Coss. Aerial Parts Endemic to Bani Waleed, Libya. Libyan Open University Journal of Applied Sciences (LOUJAS), 2(1), 97-103.
[8] Salem, M. O. A., Ahmed, G. S., Abuamoud, M. M. M., & Rezgalla, R. Y. M. (2025). Antimicrobial Activity of Extracts of Dandelion (Taraxacum officinale) Against Escherichia coli and Staphylococcus aureus: Mechanisms, Modern Insights, and Therapeutic Potential. Libyan Journal of Medical and Applied Sciences, 3(2), 37-40.
[9] Salem, M. O. A., & Lakwani, M. A. S. (2024). Determination of Chemical Composition and Biological Activity of Flaxseed (Linum usitatissimum) Essential Oil. Journal of Biometry Studies, 4(2), 91-96.
[10] Salem, M., & Salem, I. (2025). Antimicrobial Polymers: Mechanisms of Action and Applications in Combating Antibiotic Resistance. Al-Imad Journal of Humanities and Applied Sciences (AJHAS), 1(1), 12-15.
[11] Soof, S. A., Sauf, M. A., Salim, A. A. A., & Salem, M. O. A. (2025). GC-MS Quantification of Bioactive Isothiocyanates in Sinapis alba Essential Oil and Validation of Rapid Bactericidal Kinetics Against Clinically Relevant Pathogens. Scientific Journal for Publishing in Health Research and Technology, 1(2), 86-93.
[12] Akroum, S. (2017). Antibacterial activity of Tilia cordata extracts against multidrug-resistant bacteria. Journal of Applied Pharmaceutical Science, 7(5), 123-128.
[13] Alves-Silva, J. M., Dias dos Santos, S. M., Pintado, M. E., & Pérez-Álvarez, J. A. (2019). Chemical composition and antimicrobial activity of Tilia spp. flowers extracts. Industrial Crops and Products, 132, 527-535.
[14] Boukhatem, M. N., Ferhat, M. A., & Kameli, A. (2020). Medicinal plants with antimicrobial activity against Escherichia coli: A systematic review. Phytotherapy Research, 34(8), 1842-1861.
[15] Čakar, U., Grozdanić, N., & Miljković, B. (2021). Phenolic profile and antibacterial activity of Tilia cordata extracts. Natural Product Communications, 16(2), 1-8.
[16] Fratianni, F., Cozzolino, A., & Nazzaro, F. (2018). Phenolic composition and antimicrobial activity of Tilia spp. extracts. Food Chemistry, 245, 1014-1020.
[17] Gürbüz, I., Üstün, O., & Yesilada, E. (2019). Anti-inflammatory and antimicrobial activities of Tilia cordata flowers. Journal of Ethnopharmacology, 235, 112-119.
[18] Hossain, M. A., Al-Hdhrami, S. S., & Weli, A. M. (2020). Antimicrobial activity of medicinal plants against multidrug-resistant Escherichia coli. Asian Pacific Journal of Tropical Medicine, 13(5), 193-201.
[19] Karakaş, S., & Özgen, U. (2019). Antimicrobial activity of some Tilia species growing in Turkey. Marmara Pharmaceutical Journal, 23(3), 456-463.
[20] Khalil, A. A., & Rahman, U. (2020). Medicinal plants as alternative therapy for urinary tract infections. Journal of Herbal Medicine, 24, 100395.
[21] Moussaoui, F., & Zellagui, A. (2021). Phytochemical analysis and antimicrobial activity of Tilia cordata Mill. leaves from Algeria. South African Journal of Botany, 138, 234-240.
[22] Mulyaningsih, S., Sporer, F., & Reichling, J. (2019). Antibacterial activity of essential oils from Tilia spp. against uropathogens. Planta Medica, 85(8), 632-639.
[23] Naz, R., & Bano, A. (2020). Phytochemical screening and antimicrobial potential of traditional medicinal plants against urinary tract infection pathogens. Pakistan Journal of Pharmaceutical Sciences, 33(2), 721-730.
[24] Ozdemir, S., & Goksu, S. (2018). Total phenolic content and antimicrobial activity of Tilia cordata extracts. Journal of Food Processing and Preservation, 42(4), e13572.
[25] Polat, R., & Cakilcioglu, U. (2017). Ethnobotanical study on medicinal plants used for urinary tract infections. Bangladesh Journal of Botany, 46(3), 1049-1057.
[26] Rashed, K., & Butnariu, M. (2020). Antimicrobial activity of Tilia cordata extracts against multidrug-resistant bacteria. Journal of Pure and Applied Microbiology, 14(1), 489-496.
[27] Salem, M. O. A. (2023). Epidemiology of urinary tract infections and antibiotic resistance patterns in North Africa. Libyan Journal of Medical Sciences, 7(2), 45-52.
[28] Tadesse, S., & Asres, K. (2021). Medicinal plants as a source of new antimicrobials for urinary tract infections. Ethiopian Pharmaceutical Journal, 35(1), 12-28.
[29] Türkmen, N., & Velioglu, Y. S. (2019). Effects of extraction solvents on the phenolic composition and antimicrobial activity of Tilia cordata. Journal of Food Science and Technology, 56(5), 2587-2595.
[30] World Health Organization. (2022). Global antimicrobial resistance surveillance system (GLASS) report: Early implementation 2022. WHO.
[31] Yousef, F. S., & Labib, R. M. (2020). Antimicrobial activity of Tilia cordata cultivated in Egypt. Egyptian Journal of Chemistry, 63(7), 2675-2684.
[32] Zaranyika, M. F., & Nyoni, H. (2019). Phytochemical composition and antibacterial activity of Tilia species. African Journal of Biotechnology, 18(25), 567-578.
[33] Zhang, L., & Xu, J. (2021). Mechanisms of action of plant flavonoids against bacterial pathogens. Frontiers in Microbiology, 12, 682-695.
