Phytochemical screening and antibacterial activity of Cola nitida seed on selected bacterial isolates

Kola nut (Cola nitida) is chewed in many West African cultures and it is used ceremonially, industrially, medicinally and economically. The aim of this study was to assess the phytochemical properties and antibacterial activity of Cola nitida seeds. The seeds were purchased, dried and then powdered for phytochemical screening and extraction. Ethanol and aqueous (hot water) extracts were used for this study. The antibacterial activity of each extract at 30 mg/ml and 60 mg/ml was tested on four bacterial isolates; Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli using the disc diffusion method on Mueller Hinton agar. The results revealed the presence of various potent phytochemicals such as alkaloids, polyphenols, tannins, flavonoids and glycosides. The zones of inhibition ranged from 0.0 mm to 28.0 mm for both concentrations of the ethanol extract and from 0.0 mm to 31.0 mm for both concentrations of the aqueous extract. The Minimum Inhibitory Concentration (MIC) ranged from 7.5 mg/ml to 30.0 mg/ml for the ethanol extract and 3.75 mg/ml to 30.0 mg/ml for the aqueous extract. No minimum bactericidal concentration was recorded. Analysis of variance (ANOVA) performed on the data showed that there were significant differences in the zones of inhibition for each concentration of the extracts (P<0.05). The purified extract of Cola nitida seeds can be used to treat infections caused by these selected bacterial species.