Synergistic effect of menthol on in-vitro antibacterial activity of Garcinia kola against Gram positive Bacteria: A preliminary study

In vitro antibacterial activity of aqueous and ethanol extracts of Garcina kola seeds and synergistic effect of menthol was investigated against selected Gram positive bacteria using agar diffusion method. The following bacteria were used as test microorganisms Staphylococcus aureus, Streptococcus pneumoniae, Staphylococcus epidermidis and Micrococcus luteus. Results obtained showed that only S. epidermidis was susceptible to aqueous extract while the remaining organisms did not show any susceptibility. It was also observed that S. pneumoniae did not show any susceptibility to ethanol extract. The Minimum Inhibitory Concentration (MIC) ranged between 25mg/ml and 200mg/ml. M. luteus showed the highest zone of inhibition (24mm). The least zone of inhibition (10mm) was observed in S. aureus and S. epidermidis. A different result was obtained when the organisms was tested with combinations of ethanol, aqueous and menthol. S. aureus, S. epidermidis and M. luteus became susceptible to ethanol extract when menthol was added likewise S. aureus and M .luteus became susceptible to aqueous extract with 5mm and 8mm as MIC respectively. Further study is required to ascertain the phytochemicals present in this plant seeds.