COMPARATIVE EVALUATION OF THE ANTIBACTERIAL EFFICACY AND PHYTOCHEMICAL PROFILE OF METHANOL AND AQUEOUS EXTRACTS OF Vernonia amygdalina AGAINST GASTROENTERITIS CAUSING BACTERIA
Abstract
Vernonia amygdalina, commonly known as bitter leaf, is a shrub recognized for its bioactive compounds with documented antibacterial properties against gastroenteritis. However, the efficacy of methanolic and aqueous extracts of Vernonia amygdalina leaves has not been extensively evaluated. This study aimed to assess the efficacy of these extracts and determine their chemical composition, as well as their potential to inhibit the activity of selected bacteria associated with gastroenteritis. Vernonia amygdalina leaves were procured from Gombe central market, and the extracts were subjected to phytochemical screening. Three distinct bacterial isolates (Salmonella typhi, Escherichia coli, and Staphylococcus aureus) associated with gastroenteritis were obtained from the microbiology laboratory at Gombe State University and used in an antibacterial assay of the leaf extracts at varying concentrations (12.5 mg/mL, 25 mg/mL, 50 mg/mL, and 100 mg/mL), conducted using the agar well diffusion method. The results confirmed the presence of tannins, alkaloids, flavonoids, steroids, and saponins, and their antimicrobial action on the isolates. The methanol extract demonstrated a significantly higher inhibition zone of 15.1 mm at 100 mg/mL against E. coli, compared to 14.0 mm for the aqueous extract against S. typhi, suggesting methanol as a more effective solvent for extracting antibacterial compounds from Vernonia amygdalina.
References
Adetunji, C. O., Olaniyi, O. O., & Ogunkunle, A. T. J. (2013). Bacterial activity of crude extracts of Vernonia amygdalina on clinical isolates. Journal of Microbiology and Antimicrobials, 5, 6064. https://doi:10.5897/JMA11.033
Akinmoladun, A. C., Ibukun, E. O., Afor, E., Obuotor, E. M., & Farombi, E. O. (2007). Phytochemical constituents and antioxidant activity of extract from leaves of Ocimum gratissimum. Scientific Research and Essay, 2(5), 163-166.
Alara, O. R., Abdurahman, N. H., Mudalip, S. A., & Olalere, O. A. (2019). Effect of drying methods on the free radicals scavenging activity of Vernonia amygdalina growing in Malaysia. Journal of King Saud University-Science, 31(4), 495-499. https://doi.org/10.1016/j.jksus.2017.05.018
Ali, M., Diso, S. U., Waiya, S. A., & Abdallah, M. S. (2019). Phytochemical screening and antibacterial activity of bitter leaf (Vernonia amygdalina). Annals of Microbiology and Infectious Diseases, 2, 17.
Ali, M., Yahaya, A., Zage, A., & Yusuf, Z. (2017). In-vitro antibacterial activity and phytochemical screening of Psidium guajava on some enteric bacterial isolates of public health importance. Journal of Advanced Medical and Pharmaceutical Sciences, 12, 17. https://doi.org/10.9734/jamps/2017/31126
Arawande, J. O., Amoo, I. A., & Lajide, L. (2012). Phytochemical and antioxidant characterization of fireweed and African lettuce. Journal of Applied Technology in Environmental Sanitation, 2(4), 191-196.
Azuamah, Y., Azuamah, F., Eluchie, E., & Johnson, C. (2024). Antibacterial activities of ethanolic and aqueous extracts of Vernonia amygdalina (bitter leaf). Nigerian Journal of Parasitology, 45(2), 1-9. https://doi.org/10.4314/njpar.v45i2.5
Bello, A., Galadima, M. S., & Aliyu, F. S. (2024). Comparative study of phytochemicals composition of Mangifera indica (mango) and Vernonia amygdalina (bitter leaf) leaves and their antimicrobial activities. International Journal of Scientific Research in Chemical Sciences, 11(6), 1-7. https://www.isroset.org/journal/ijsrcs/abstract/10156
Erasto, P., Grierson, D. S., & Afolayan, A. J. (2006). Bioactive sesquiterpene lactones from the leaves of Vernonia amygdalina. Journal of Ethnopharmacology, 106(1), 117-120. https://doi.org/10.1016/j.jep.2005.12.016
Etim, K. H., Ofor, S. E., Mandor, U. A., & Ogar, M. (2012). Evaluation of the antibacterial potential of Vernonia amygdalina on foodborne pathogens isolated from kunu sold in Calabar, Nigeria. Journal of Microbiology and Biotechnology Research, 2, 778782. http://scholarsresearchlibrary.com/JMB-vol2-iss5/JMB-2012-2-5-778-782.pdf
Farombi, E. O., & Owoeye, O. (2011). Antioxidative and chemopreventive properties of Vernonia amygdalina and Garcinia biflavonoid. International Journal of Environmental Research and Public Health, 8, 25332555. https://doi.org/10.3390/ijerph8062533
Gashe, F., & Zeleke, G. (2017). Antimicrobial activities of Vernonia amygdalina Del and Prunus africana extracts against multidrug-resistant clinical strains. Research Journal of Medicinal Plants, 11, 142147. http://docsdrive.com/pdfs/academicjournals/rjmp/2017/142-147.pdf
Gberikon, G. M., Iyoula, F. I., & Ichor, S. T. (2019). Effect of bitter leaves extract on bacteria isolated from soils of some mechanic and non-mechanic sites in Makurdi metropolis. International Journal of Applied Science and Biotechnology, 7, 8187. https://doi.org/10.3126/ijasbt.v7i1.23302
Ghamba, P., Balla, H., Goje, L., Halidu, A., & Dauda, M. (2014). In vitro antimicrobial activities of Vernonia amygdalina on selected clinical isolates. International Journal of Current Microbiology and Applied Sciences, 3(4), 11031113. http://www.ijcmas.com/vol-3-4/P.E.Ghamba,%20et%20al.pdf
Izevbigie, E. B., Bryant, J. L., & Walker, A. (2004). A novel natural inhibitor of extracellular signal-regulated kinases and human breast cancer cell growth. Experimental Biology and Medicine (Maywood), 229(2), 163-169. https://doi.org/10.1177/153537020422900205
Luo, X., Jiang, Y., Fronczek, F. R., Lin, C., Izevbigie, E. B., Lee, S., & Lee, K. S. (2017). Isolation and structure determination of a sesquiterpene lactone (Vernodalinol) from Vernonia amygdalina extracts. Pharmaceutical Biology, 49(5), 464470. https://doi.org/10.3109/13880209.2010.523429
Robinson, V. K., Nnamdi, A. U., & Korobe, B. P. (2020). Antifungal activity of local gin (kai kai) extract of Andrographis paniculata on fungal isolates. International Journal of Research and Innovation in Applied Science (IJRIAS), 5, ISSN 2454-6194.
Yada, R., & Agarwala, M. (2011). Phytochemical analysis of some medicinal plants. Journal of Phytology, 3(12), 10-14. http://journal-phytology.com/
Zubairu, A. Y., Mukhtar, M., Saidu, I., Ibrahim, Z., Isah, S., Garga, M. A., et al. (2019). Antibacterial activity of methanolic extract of bitter leaf (Vernonia amygdalina) from various component fractions using column chromatography. GSC Biological and Pharmaceutical Sciences, 7, 1621. https://doi.org/10.30574/gscbps.2019.7.2.0095
Copyright (c) 2025 FUDMA JOURNAL OF SCIENCES
This work is licensed under a Creative Commons Attribution 4.0 International License.
FUDMA Journal of Sciences
