Phytochemical screening and antibacterial activity of Garcinia kola (hackel) and Cola nitida (vent) extracts

This study was designed to evaluate the phytochemical and antibacterial properties of Garcina kola (Orogbo) and Cola nitida (Obi) extracts. Fresh seeds of Cola nitida and Garcinia kola were collected from Ago-Iwoye market, Ogun State. The ethanolic and aqueous extracts of the test plants were used against selected test organisms, Streptococcus pneumonia, Staphylococcus aureus, Salmonella typhi, Pseudomonas euriginosa and Escherichia coli. Disc diffusion method was adopted to test for susceptibility of the selected test bacteria to the extracts. Minimum inhibition concentration (MIC) and Minimum bactericidal concentration (MBC) were determined. Bioassay data were statistically analyzed using two-way ANOVA. The result of the phytochemical screening confirmed the presence of flavonoid, phenol, alkaloid, saponins, tannins and phlobatanins. The result of the antibacterial activity showed that the ethanolic extract of the test plants recorded highest antimicrobial activity against test isolates compared to aqueous extracts. The tested plant seeds of both plants posses reasonable antibacterial activity but to varied zones of inhibition, with Staphylococcus aureus isolate having the highest inhibitory zones (21.33) mm while Pseudomonas aeuruginosa had the least inhibitory zone (6.00) mm. The antibacterial activity were however found to be concentration dependent (Fvalue= 3.996, Pvalue= < 0.05). All tested organisms were found to have definite MIC and MBC activities which ranges between 125 and 1000μg/ml for MIC except for Kola nitida that has no definite MBC below 1000μg/ml. The result confirms the potential of antibacterial activity of Garcinia kola and Cola nitida extracts. Keywords: Antimicrobial, Cola nitida, Garcinia kola, Phytochemical, Plant extracts