Phytochemical and Antimicrobial Screening of Gnetum Africanum Stem and Root

Main Article Content

B. C. Akin-Osanaiye
E. J. Ekpeyong
I. W. Olobayotan


The menace of antibiotic resistance and the antecedent evolution of innocuous microbes into superbugs is an epidemic of global concern. This study investigated the phytochemical and antimicrobial activity of hexane and methanol extracts of Gnetum africanum stem and root, on Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi and Aspergillus flavus. Stem and roots of G. africanum were extracted with hexane and methanol using cold maceration technique; standardized chemical tests were employed for phytochemical screening and the agar-well diffusion method used for antimicrobial analysis. The results of phytochemical screening G. africanum showed that all the following tested phytochemicals which include steroid, tannins, and saponins were present in both methanol and hexane extracts of G. africanum while flavonoids, alkaloids, glycosides and carbohydrate were absent in both the methanol and hexane extracts. Anthraquinone was present in hexane extract but absent in methanolic extract of G. africanum. Both the stem and root of G. africanum had antimicrobial effects on all the test organisms but the effect of the stem was higher than that of the root. Findings indicate that both extracts had a dose-dependent inhibitory effect on the growth of S. aureus, with maximum inhibition zones of 17.50 mm and 16.00 mm at 500 mg/ml for hexane and methanol extracts, respectively. The stem and root extracts of hexane and methanol were inactive against A. flavus. The findings of this study further reinforce the importance of G. africanum stem and root in traditional healthcare practice and its use in culinary. Further investigation is however needed to isolate and purify the bioactive antimicrobial principles for potential development into generic antimicrobials.

Antibiotic resistance, Gnetum africanum, antimicrobial activity, phytochemicals, cold maceration technique.

Article Details

How to Cite
Akin-Osanaiye, B. C., Ekpeyong, E. J., & W. Olobayotan, I. (2019). Phytochemical and Antimicrobial Screening of Gnetum Africanum Stem and Root. International Journal of Pathogen Research, 3(2), 1-11.
Original Research Article


Bari MA, Islam W, Khan AR, Mandal A. Antibacterial and antifungal activity of Solanum torvum (Solanaceae). International Journal of Agricultural Biology. 2010;12:386-390.

Azoro C. Antibacterial activity of crude extracts of Azudirachia indica on Salmonella typhi. World Journal Biotechnology. 2002;3:354-357.

Mialoundama F. Nutritional and socio-economic values of Gnetum leaves in central African forest. Parthenon Publication, New York. 1993;181.

Trease G, Evans WC. Phytochemicals. In: Pharmagcognosy. London: Saunders Publishers. 2002;386-400.

Cheesbrough M. District Laboratory Practices in Tropical Countries (part 2). Great Britain: Tropical Health Technology Publishers. 2002;40-56.

Akharaiyi, FC. Antibacterial, phytochemical and antioxidant activities of Datura metel Linn. International Journal of Pharmacology and Technology Research. 2011;3(1):478-483.

Banso A, Adeyemo SO. Evaluation of antibacterial properties of tannins isolated from Dichrostachys cinerea. African Journal of Biotechnology. 2006;6:1785-1787.

Njoku PC, Akumefula MI. Phytochemical and nutrient evaluation of Spondias mombin Leaves. Pak Journal Nutrition. 2007;6:613-615.

Okonkwo SI. Isolation and characterization of tannin metabolites in Spondias mombin (Linn) (Anacardiaceae). National Applied Science Journal. 2009;10:21-29.

Wright GD. Something new: Revisiting natural products in antibiotic drug discovery. Canadian Journal of Microbiology. 2014;60(3):147-154.

Ilodibia CV, Ugwu RU, Nwokolo OI, Chukwuma MU, Akachukwu EE. Phytochemical screening, antifungal and antibacterial activity of aqueous and ethanolic leaf and stem extracts of Gnetum africanum Welw. Research Journal of Medicinal Plant. 2015;9(6):275-283.

Timothy SY, Lamu FW, Rhoda AS, Adati RG, Maspalma ID, Askira M. Acute toxicity, phytochemistry and antibacterial activity of aqueous and ethanolic leaf extracts of Cassia alata Linn. International Research Journal of Pharmacy. 2012;3(6):73-76.

Abubacker MN, Ramanathan R, Senthil KT. In vitro antifungal activity of Cassia alata linn flower extract. Natural Product Radiance. 2008;7(1):6-9.

Stein AC, Sortino M, Avaocini C, Zacchino, S, von Poser G. Ethnoveterinary medicine in the search for antimicrobial agents: Antifungal activity of some species of Pterocaulon (Asteracaeae). Journal of Ethnopharmacology. 2005;99:211-214.

Eneh FU, Onwubiko CE, Ugochukwu GC. Phytochemical and antimicrobial activity screening of Gnetum africanum leaf extracts. International Journal of Herbal Medicine. 2017;5(3):105-109.

Enyi-Idoh KH, Ikpeme EM, Iwuh GC, Egeonu SU, Mandor BI, Ofor UA. Antibacterial activity of Gnetum africanum and Heinsia crinata on diarrhoegenic stool isolates from children in Calabar South LGA, Cross River State, Nigeria. Translational Journal of Science and Technology. 2013;3(3):28-36.