Phytochemical and Antimicrobial Screening of Gnetum Africanum Stem and Root

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.