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Research Article






Olakunle AI, Olawale SI, Damilola OE, Onayi AS

Abstract: The incidence of antibiotic resistance is one of the challenges in the treatment of different ailments. Hence, this study focused on the use of V. amygdalina (ethanolic and methanolic) extracts on some selected bacterial isolates. Different concentrations of the extracts were prepared and the residues were re-suspended in the solvents. The zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiotic susceptibility patterns were determined according to standard methods. The ethanolic extract appeared to produce better antibacterial effect than methanolic extract. K. pneumoniae and S. marcescens were inhibited by ethanolic extract of 12.5-200mg/ml used. However, only S. aureus was inhibited by all methanolic extract concentrations used. Most of the isolates (83.3%) had lower MIC in ethanolic extract when compared with methanolic extract. The MIC of the isolates in the ethanolic and methanolic extracts ranged from 12.5-100mg/ml and 25-100mg/ml respectively. Two of the isolates, B. cereus and K. pneumoniae did not cease to grow on MBC plates even at the highest concentration of 200mg/ml used. All the isolates showed multiple antibiotic resistance patterns with AMR index range of 0.63-1.0. All the isolates were resistant to augmentin, cefexime, cefuroxime, ceftazidime and nitrofurantoin. The order of susceptibility of the isolates to the antibiotics were gentamicin (83.3%) > ofloxacin (66.7%) > ciprofloxacin (33.3%). It is concluded in this study that the extracts of V. amygdalina inhibited 83% of the isolates at lower concentration of 25mg/ml, were bactericidal at 100-200mg/ml for 66.7% of the isolates and produced higher inhibition zone in comparison with the standard antibiotics on the isolates.


KEYWORDS: Antibacterial activity, Vernonia amygdalina, Antibiotics, Inhibition


  1. [1] Yedjou C, Izevbigie E, Tchounwou P. Preclinical assessment of Vernonia amygdalina leaf extracts as DNA damaging anti-cancer agent in the management of breast Cancer. Inter. J. Environ. Res. Public Health 2008; 12:123-127.

  2. [2] Azoro C. Towards effective integration of herbal medicine into Nigerian medical practice. Nig. J. Res. Prod. 2004; 3: 132-137.

  3. [3] Rosina K, Barrira I, Mohd A, Shazi S, Anis A, Manazir SA, Mashiatullah S, Asad UK. Antimicrobial activity of five herbal extracts against muti-drug reserve (MDR) strains of Bacteria and Fungi of clinical origin. Molecule 2009; 14:586-597.

  4. [4] Akinjogunla OJ, Ekoi OH, Odeyemi AT, Akinjogunla OJ, Etok CA, Oshoma CE. Preliminary phytochemistry and in-vitro antibacterial efficacy of Hydro-Ethanolic leaf extracts of Psidium guajava on common urinary tract bacterial pathogens. Biores. Bull. 2011; 5: 329-336.

  5. [5] Tula MY, Azih AV, Iruolaje FO, Okojie RO, Elimian KO, Toy BD. Systematic study on comparing phytochemicals and the antimicrobial activities from different parts of V. amygdalina. African Journal of Microbiology Research 2012; 43, 6:7089-7093.

  6. [6] Bukar AM, Isa MA, Beklo HS, Abdullahi AS. Antimicrobial activity of ethanolic leaf extract of Vernonia amygdalina on selected species of Gram positive and Gram negative bacteria. International Journal of Environment 2013; 2, 1:147-152

  7. [7] Ibrahim TA, Lola A, Adetuyi FO, Jude-Ojei B. Assessment of the antibacterial activity of Vernonia amygdalina and Ocimum gratissimum leaves on selected food borne pathogens. Inter. J. Third World Med. 2009; 8, 2: 23-24

  8. [8] Anibijuwon II, Adetitun DO, Oladejo B, Kolawole OM. Antimicrobial activity of Vernonia amygdalina against oral microbes. Global Journal of Pharmacology 2012; 6, 3:178-185.

  9. [9] Izevbigie EB, Bryant JL, Walker A. A novel natural inhibitor of extracellular signal related kinases and human breast cancer cell growth. Experiment. Biol. Med. 2004; 229: 163-169.

  10. [10] Evbuomwan L, Chukwuka EP, Obazenu EI, Ilevbare L. Antibacterial activity of Vernonia amygdalina leaf extract against multi-drug resistant bacterial isolates. J. Appl. Sci, Environ. Manage. 2018; 22, 1:17-21.

  11. [11] Hiramatsu M, Takahashi T, Komatsu M, Kido T, Kasahara Y. Antioxidant and neuroprotective activities of Mogami-benibana (safflower, Carthamus tinctorius Linne). Neurochemical Research 2009; 34, 4:795–805.

  12. [12] Nalule AS, Mbaria JM, Olila D, Kimenju JW. Ethno-pharmacological practices in management of livestock helminthes by pastoral communities in the dry lands of Uganda. Livestock Research for Rural Development 2011:23.

  13. [13] Idris S, Ndukwe GI, Gimba CE. Preliminary phytochemical screening and antimicrobial activity of seed extract of Persea Americana (avocado pear). Bayero J. Pure Appl. Sci. 2009; 2, 1: 173 – 176.

  14. [14] Kouadio NJ, Guessennd NK, Kone MW, Moussa B, Koffi YM. Evaluation de l’activité des feuilles de Mallotusoppositifolius (Geisel.) Müll.-Arg (Euphorbiaceae) sur des bactéries multirésistantes et criblage phytochimique. International Journal of Biological and Chemical Sciences 2015; 9, 3:1252-1262.

  15. [15] Odeyemi AT, Fagbohun ED. Antimicrobial activities of the extracts of the peels of Dioscorea cayensis L. J. f. Appl. and Environ. Sci. 2005; 1:37-42.

  16. [16] CLSI (2020). Clinical Laboratory of Standards Institute. Performance standards for antimicrobia1 susceptibility testing. 30th ed. CLSI supplement M100, Wayne, PA, USA.

  17. [17] Ajaiyeoba EO, Onocha PA, Noozo SO, Sama W. Antimicrobial and cytotoxicity evaluation of Buchholzia coriacea stem bark. Journal of Agricultural and Environmental science 2003; 74: 706-709.

  18. [18] Uzoigwe CI, Agwa OK. Antimicrobial activity of Vernonia amygdalina on selected urinary tract pathogens. Afr. J. Microbiol. Res. 2011; 5, 12:1467-1472.

  19. [19] Ogundare AO. Antibacterial properties of the leaf extract of Vernonia amygdalina, Ocimum gratissimun, Corchorus olitorius and Manihot palmate. Journal of Microbiology and Antimicrobial 2011; 3, 4:77-86.

  20. [20] Preethi RM, Devanathan VV, Loganathan M. Antimicrobial and antioxidant efficacy of some medicinal plants against food borne pathogens. Advance in Biological Research 2010; 4: 122-125.

  21. [21] Allero AA, Afolayan AJ. Antimicrobial activity of Solanum tomentosun. Afr. J. Biotechnol. 2006; 5:269-272.

 To cite this article:

Olakunle AI, Olawale SI, Damilola OE, Onayi AS. Antibacterial activity of vernonia amygdalina extracts against multi-drug resistant gram-positive and gram-negative bacteria. Int. J. Med. Lab. Res. 2022; 7,3:.

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