The aim of the study was to investigate the phytochemical
properties and the relative antimicrobial activity of aqueous, ethanol and methanol seed extracts of Cola nitida, Cola acuminata and Garcinia kola respectively.
The phytochemicals were screened by qualitative and quantitative methods. Three different solvents: aqueous, ethanol and methanol were used to extract the bioactive compounds from the three species of Kola Qualitatively analyzed phytochemical constituents in the seed extracts of the three Cola
species included Alkaloids, tannins, flavonoids, steroids, terpenoids and cardiac glycosides. The microorganisms assayed for antimicrobial activity using the agar diffusion method were: the gram positive Staphylococcus aureus
spp, the gram-negative Escherichia coli, Pseudomonas aeruginosa
and Klebsiella pneumoniae
respectively. Studies on sensitivity patterns of zones of inhibition exhibited by the crude methanol, ethanol and aqueous extracts of Garcinia kola, Cola nitida and Cola acuminata
nuts showed relative degree of inhibitory effects against the test microorganisms: Escherichia coli, Staphylococcus aureus, Lactobacillus, Pseudomonas aeruginosa
and Klebsiella pneumonia
. The zones of inhibition for Escherichia coli
was the highest with methanol extract of 36.0mm followed by Klebsiella pneumonia
with 25.5mm followed by Staphylococcus aureus
with 23.5mm, and Pseudomonas aeruginosa
with 18.5mm and Lactobacillus
with 17.5mm respectively. Highest zones of inhibition started from methanol, ethanol and aqueous, their diameter of inhibition increases with increase in their concentrations. The methanol preparation of Garcinia cola
nut was found to exhibit more significant inhibitory action (p<0.05) against the test organisms than the ethanol and aqueous preparations of Garcinia kola and those of C. nitida and C. acuminata
. Escherichia coli
in both preparations gave widest zones of inhibition than other microorganisms. Cola spp
extracts with methanol can be explored in the development of drugs against infectious diseases.
Dr. Efe M Omwirhiren, Asefon O Abass and Stephen A James. The phytochemical constituents and relative antimicrobial activities against clinical pathogens of different seed extracts of Cola nitida (Vent.), Cola acuminata (Beauvoir) and Garcinia kola (Heckel) grown in South West, Nigeria. J Pharmacogn Phytochem 2017;6(1):493-501.