Comparative Antimicrobial Activities of a Consortium of Vernonia amygdalina and Amaranthus hybridus Extracts With Their CuO Nanoparticle Complexes

Document Type : Original Article


1 Department of Industrial Chemistry, University of Ilorin, Ilorin Kwara State, Nigeria

2 Department of Microbiology, University of Ilorin, Ilorin Kwara State, Nigeria


Introduction: The synthesis of nanoparticles from plant extracts has gained much attention in recent times. This study aimed at screening a consortium of crude extracts of Vernonia amygdalina and Amaranthus hybridus for antimicrobial activities.
Methods: The activities were compared with nanoparticles synthesized using the extracts. Powdered plant materials were separately suspended in distilled water and ethanol which were filtered to obtain crude extracts, while plant nanoparticles were synthesized by coupling with copper oxide (CuO). Crude extracts were screened for the presence of bioactive constituents. Antibacterial assay was carried out by agar well diffusion, while the poisoned plate technique was used to determine antifungal activity.
Results: Plant extracts revealed the presence of alkaloids, steroids, saponins, and tannins. The aqueous crude extract produced higher activity than the ethanolic extract with the highest inhibition zone (29) against Bacillus megaterium at a concentration of 40 mg/mL. Antifungal activity also showed that the aqueous extract was better than the ethanolic one. The aqueous nanoparticle extract was higher in antimicrobial activities compared to its crude counterpart, exhibiting inhibition zones of 34 mm at 40 mg/mL and 31 mm at 60 mg/mL for antibacterial and antifungal assays, respectively.
Conclusions: The results of this study indicate that aqueous extracts demonstrated higher antimicrobial activity than ethanolic ones, and the synthesis of nanoparticles using a consortium of 2 plants has the potential to enhance antimicrobial activity.


  1. Aruoma OI, Sun B, Fujii H, et al. Low molecular proanthocyanidin dietary biofactor Oligonol: Its modulation of oxidative stress, bioefficacy, neuroprotection, food application and chemoprevention potentials. Biofactors. 2006;27(1-4):245-265. doi:10.1002/biof.5520270121.
  2. Kupchan SM, Hemingway RJ, Karim A, Werner D. Tumor inhibitors. XLVII. Vernodalin and vernomygdin, two new cytotoxic sesquiterpene lactones from Vernonia amygdalina Del. J Org Chem. 1969;34(12):3908-3911. doi:10.1021/jo01264a035.
  3. Muraina IA, Adaudi AO, Mamman M, et al. Antimycoplasmal activity of some plant species from northern Nigeria compared to the currently used therapeutic agent. Pharm Biol. 2010;48(10):1103-1107. doi:10.3109/13880200903505633.
  4. Challand S, Willcox M. A clinical trial of the traditional medicine Vernonia amygdalina in the treatment of uncomplicated malaria. J Altern Complement Med. 2009;15(11):1231-1237. doi:10.1089/acm.2009.0098.
  5. Ajaiyeoba EO, Onocha PA, Nwozo SO, Sama W. Antimicrobial and cytotoxicity evaluation of Buchholzia coriacea stem bark. Fitoterapia. 2003;74(7-8):706-709. doi:10.1016/S0367-326X(03)00142-4.
  6. He HP, Corke H. Oil and squalene in amaranthus grain and leaf. J Agric Food Chem. 2003;51(27):7913-7920. doi:10.1021/jf030489q.
  7. Udochukwu U, Omeje FI, Uloma IS, Oseiwe FD. Phytochemical analysis of Vernonia amygdalina and Ocimum gratissimum extracts and their antibacterial activity on some drug resistant bacteria. Am J Res Commun. 2015;3(5):225-235.
  8. Shekhawat MS, Manokari M, Kannan N, Revathi J, Latha R. Synthesis of silver nanoparticles using Cardiospermum halicacabum L. leaf extract and their characterization. J Phytopharmacol. 2013;2(5):15- 20.
  9. Pirtarighat S, Ghannadnia M, Baghshahi S. Green synthesis of silver nanoparticles using the plant extract of Salvia spinosa grown in vitro and their antibacterial activity assessment. J Nanostructure Chem. 2019;9(1):1-9. doi:10.1007/s40097-018-0291-4.
  10. Chanda S, Dave R. In vitro models for antioxidant activity evaluation and some medicinal plants possessing antioxidant properties: An overview. Afr J Microbiol Res. 2009;3(13):981-996.
  11. Ahmed RN, Sani A, Ajiboye AE, Gambari-Ambali RO, Ezekiel Ku. Sensitivity of three gastro-intestinal organisms to aqueous extract of leaf of Ocimum gratissimum. Nigeria Journal of Pure and Applied Sciences. 2013;26:2460-2469.
  12. Ahmed RN, Sani A, Igunnugbemi OO. Antifungal profiles of extracts of Vitellaria paradoxa (Shea-Butter) bark. Ethnobotanical leaflets. 2009;13:679-688.
  13. Pal S, Tak YK, Song JM. Does the antibacterial activity of silver nanoparticles depend on the shape of the nanoparticle? A study of the Gram-negative bacterium Escherichia coli. Appl Environ Microbiol. 2007;73(6):1712-1720. doi:10.1128/AEM.02218-06.
  14. Blanco JG, Gil RR, Bocco JL, Meragelman TL, Genti-Raimondi S, Flury A. Aromatase inhibition by an 11,13-dihydroderivative of a sesquiterpene lactone. J Pharmacol Exp Ther. 2001;297(3):1099- 1105.
  15. Mabhiza D, Chitemerere T, Mukanganyama S. Antibacterial Properties of Alkaloid Extracts from Callistemon citrinus and Vernonia adoensis against Staphylococcus aureus and Pseudomonas aeruginosa. Int J Med Chem. 2016;2016:6304163. doi:10.1155/2016/6304163.
  16. Tomee JF, Kauffman HF. Putative virulence factors of Aspergillus fumigatus. Clin Exp Allergy. 2000;30(4):476-484. doi:10.1046/j.1365-2222.2000.00796.x.
  17. Prabhu S, Poulose EK. Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects. Int Nano Lett. 2012;2(1):32. doi:10.1186/2228-5326-2-32.
  18. Parekh J, Chanda S. In vitro antibacterial activity of the crude methanol extract of Woodfordia fruticosa Kurz. Flower (Lythraceae). Braz J Microbial. 2007;38(2):204-207. doi:10.1590/S1517-83822007000200004.
  19. Suleiman MN. The in vitro phytochemical investigation on five medicinal plants in Anyigba and its environs, Kogi State, Nigeria. Der Pharmalia Sinica. 2011;2(4):108-111.