Phytochemical and Antibacterial Properties of Garcinia kola Seeds (Bitter kola) on Escherichia coli and Staphylococcus aureus

  • Valentine N. Unegbu
  • Florence N. Okey-Ndeche
  • Charity N. Obum-Nnadi
  • Pius I. Egwuatu
Keywords: Garcinia kola, Ethanolic, Aqueous, Methanolic, Staphylococcus aureus, Escherichia coli


The different parts of plants such as seed, leaves, barks and root contain medicinal substances. These substances produce definite physiological action in the human body. This present study was aimed to investigate the phytochemical and antibacterial properties of methanolic, ethanolic and aqueous extracts of Garcinia kola (bitter kola) on Staphylococcus aureus and Escherichia coli. The phytochemical constituents were carried out using standard methods. The antibacterial activities of the plant extracts was determined using agar-well diffusion method. The Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the plant extracts on the test isolates were determined by micro-broth dilution method. Phytochemical analysis shows that Phenols, flavonoids, glycosides, tannin, saponin, alkaloids and anthraquinolones were present in varying concentrations of the different extracts. The methanol extract of G. kola seed possesses more antimicrobial activity (17-25 mm) in a concentration dependent manner than the ethanol extract (10-21 mm) and then aqueous extract (7-17mm). The MIC of different extracts of S. aureuswas between 12.5mg/ml to 50mg/ml while that of E. coli was also between 12.5mg/ml to 50mg/ml. The MBC of different extracts of S. aureus and E. coli isolates were both between the ranges of 25 to 100mg/ml. It can be concluded that some secondary metabolites present in Garcinia kola seed was responsible for the inhibition of the bacteria observed in this study; thus, the test plant could be used to manufacture drugs that could be used to treat infections caused by the test organisms.