Abstract
Gastrointestinal infections associated with vomiting and rapid dehydration represent a major cause of morbidity among children under 5 years of age in Kisangani. Faced with the rise of bacterial resistance to conventional antibiotics, searching for alternative bioactive substances from the local flora has become essential. This study aims to evaluate in vitro the antibacterial activity of tomato leaf extracts (Solanum lycopersicum L.) against Escherichia coli, Salmonella spp., and Staphylococcus aureus strains isolated from the vomitus of children aged 6 to 59 months in the city of Kisangani. Bacterial strains were isolated and identified using standard microbiological methods. Solanum lycopersicum leaves underwent aqueous and ethanolic extraction. The antibacterial activity was determined using the agar disk/well diffusion method to measure inhibition diameters, followed by the determination of Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) in liquid media. Preliminary phytochemical screening revealed the presence of secondary metabolites of interest (glycoalkaloids such as α-tomatine, phenolic compounds, and flavonoids). The leaf extracts of Solanum lycopersicum exhibited a dose-dependent inhibitory effect against all tested pathogens. Ethanolic extracts showed higher efficacy compared to aqueous extracts, which was particularly pronounced against Staphylococcus aureus (Gram-positive) than against the enterobacteria E. coli and Salmonella spp. (Gram-negative). Solanum lycopersicum leaves contain active principles endowed with significant in vitro antibacterial properties. These preliminary results justify further investigations to evaluate the toxicity and therapeutic potential of these extracts.
References
1. Abdel-Razek, M. A. M., Abdelwahab, M. F., Abdelmohsen, U. R., & Hamed, A. N. E. (2025). Phytochemical and biological biodiversity of tomato (Solanum lycopersicum L.) (2010–2022). Current Pharmaceutical Biotechnology, 26(15), 1149–1185.
2. Alves, T. M. A., Silva, A. F., Brandão, M., et al. (2000). Biological screening of Brazilian medicinal plants. Memórias do Instituto Oswaldo Cruz, 95(3), 367–373.
3. Atanasov, A. G., Waltenberger, B., Pferschy-Wenzig, E. M., et al. (2015). Discovery and resupply of pharmacologically active plant-derived natural products: A review. Biotechnology Advances, 33(8), 1582–1614.
4. Azwanida, N. N. (2015). A review on the extraction methods use in medicinal plants, principle, strength and limitation. Medicinal & Aromatic Plants, 4, 196.
5. Balouiri, M., Sadiki, M., & Ibnsouda, S. K. (2016). Methods for in vitro evaluating antimicrobial activity: A review. Journal of Pharmaceutical Analysis, 6(2), 71–79.
6. Bauer, A. W., Kirby, W. M. M., Sherris, J. C., & Turck, M. (1966). Antibiotic susceptibility testing by a standardized single disk method. American Journal of Clinical Pathology, 45(4), 493–496.
7. Bucar, F., Wube, A., & Schmid, M. (2013). Natural product isolation—How to get from biological material to pure compounds. Natural Product Reports, 30(4), 525–545.
8. Burt, S. (2004). Essential oils: Their antibacterial properties and potential applications in foods—A review. International Journal of Food Microbiology, 94(3), 223–253.
9. Croxen, M. A., Law, R. J., Scholz, R., Keeney, K. M., Wlodarska, M., & Finlay, B. B. (2013). Recent advances in understanding enteric pathogenic Escherichia coli. Clinical Microbiology Reviews, 26(4), 822–880.
10. Cushnie, T. P. T., & Lamb, A. J. (2005). Antimicrobial activity of flavonoids. International Journal of Antimicrobial Agents, 26(5), 343–356.
11. Daglia, M. (2012). Polyphenols as antimicrobial agents. Current Opinion in Biotechnology, 23(2), 174–181.
12. Eng, S. K., Pusparajah, P., Ab Mutalib, N. S., Ser, H. L., Chan, K. G., & Lee, L. H. (2015). Salmonella: A review on pathogenesis, epidemiology and antibiotic resistance. Frontiers in Life Science, 8(3), 284–293.
13. Falanga, C.M., Kilembe, J.T., Matondo, A., Ngbolua, K.T.N., Mpiana, P.T., Mudogo, V. (2026). Natural products from Congolese plant biodiversity as potential inhibitors of COVID-19 main protease (3CLpro/Mpro) and angiotensin-converting enzyme-2 (ACE-2): Insights from molecular docking and molecular dynamics simulations. Pharmacological Research-Natural Products, 10, 100571. https://doi.org/10.1016/j.prenap.2026.100571.
14. Kabengele, C.N., Ngoyi, E.M., Kasiama, G.N., Kilembe, J.T., Matondo, A. (2020). Antihelminthic activity, phytochemical profile and microscopic features of Ocimum basilicum collected in DR Congo. Asian Journal of Biology,10(3), 42-50.
15. Kaper, J. B., Nataro, J. P., & Mobley, H. L. T. (2004). Pathogenic Escherichia coli. Nature Reviews Microbiology, 2(2), 123–140.
16. Lukuzu, T., Bala, N.E., Kavira, R., Nyampondo, N., Mulumba, B. et al. (2024). In vitro screening, molecular docking, and ADME-Tox investigations for the design of novel beta-lactam antibiotics (Ampicillin and Ceftriaxone) derivatives as PBP2a inhibitors. Journal of Applied Biosciences 197, 20864-20885. https://doi.org/10.35759/JABs.197.6.
17. Mbadiko, C.M., Matondo, A., Bongo, G.N., Inkoto, C.L., Gbolo, B.Z., Lengbiye, E.M., Kilembe, J.T. et al. (2020). Review on Ethno-botany, virucidal activity, phytochemistry and toxicology of Solanum genus: Potential Bio-resources for the Therapeutic Management of Covid-19s. Eur J Nutr Food Saf, 12(7),35-48.
18. Mbula, J.P., Kasiama, G.N., Matondo, A., Bete, J., Ngbolua, K.T.N. et al (2023). Etude bibliographique sur la phytochimie et les activités biologiques de Eucalyptus globulus L.(Myrtaceae). Rev. Cong. Sc. Tech. 2(1), 220-232. https://doi.org/10.59228/rcst.023.v2.i1.28.
19. Mulongo, E.K., Matondo, A., Ngbolua, K.T.N., Mpiana, P.T. (2025). Evaluation of antiviral potential of Cinchona officinalis derived compounds against COVID-19 and human hepatitis B: An in silico molecular docking and molecular dynamics simulation study. Pharmacological Research-Natural Products,7,100229. https://doi.org/10.1016/j.prenap.2025.100229.
20. Murray, P. R., Baron, E. J., Jorgensen, J. H., Landry, M. L., & Pfaller, M. A. (Eds.). (2007). Manual of clinical microbiology (9th ed.). ASM Press.
21. Newman, D. J., & Cragg, G. M. (2016). Natural products as sources of new drugs from 1981 to 2014. Journal of Natural Products, 79(3), 629–661.
22. Omar, R.F., Trottier, S., Sato, S., Ouellette, M., Bergeron, M.G. (2025). Advances in the Management of Infectious Diseases. Infect Dis Rep. 14;17(2):26. doi: 10.3390/idr17020026.
23. Parekh, J., & Chanda, S. (2007). In vitro antibacterial activity of the crude methanol extract of Woodfordia fruticosa Kurz. flower (Lythraceae). Brazilian Journal of Microbiology, 38(2), 204–207.
24. Parekh, J., Jadeja, D., & Chanda, S. (2005). Efficacy of aqueous and methanol extracts of some medicinal plants for potential antibacterial activity. Turkish Journal of Biology, 29(4), 203–210.
25. Silhavy, T. J., Kahne, D., & Walker, S. (2010). The bacterial cell envelope. Cold Spring Harbor Perspectives in Biology, 2(5), a000414.
26. Tam, C. C., Nguyen, K., Nguyen, D., et al. (2021). Antimicrobial properties of tomato leaves, stems, and fruit and their relationship to chemical composition. BMC Complementary Medicine and Therapies, 21(1), 229.
27. Tiwari, P., Kumar, B., Kaur, M., Kaur, G., & Kaur, H. (2011). Phytochemical screening and extraction: A review. International Pharmaceutical Sciences, 1(1), 98–106.
28. Tshibangu, D.S.T., Matondo, A., Lengbiye, E.M., Inkoto, C.L., Ngoyi, E.M. (2020). Possible effect of aromatic plants and essential oils against COVID-19: Review of their antiviral activity. Journal of Complementary and Alternative Medical Research, 11(1), 10-22.
29. Tshidibi, J.D., Monga, M.S., Kitete, E.M., Kabena, O.A., Matondo, A. et al. (2026). Usages ethnobotaniques, composition phytochimique, activités pharmacologiques et toxicité de Hymenocardia acida Tul.: revue systématique. Rev. Cong. Sc. Techn.5(3), 1488-1501.
30. Vlietinck, A. J., Van Hoof, L., Totté, J., et al. (1995). Screening of hundred Rwandese medicinal plants for antimicrobial and antiviral properties. Journal of Ethnopharmacology, 46(1), 31–47.
31. Wallace, R. J. (2004). Antimicrobial properties of plant secondary metabolites. Proceedings of the Nutrition Society, 63(4), 621–629.
32. Williamson, E. M. (2001). Synergy and other interactions in phytomedicines. Phytomedicine, 8(5), 401–409.
33. World Health Organization. (2002). WHO monographs on selected medicinal plants (Vol. 2). World Health Organization.
34. World Health Organization. (2013). WHO traditional medicine strategy: 2014–2023. World Health Organization.
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