Determination of Antibacterial Activity of Essential Oil of Myristica fragrans Houtt. using Tetrazolium Microplate Assay and its Cytotoxic Activity Against Vero Cell Line

Essential oils and volatile constituents of Myristica fragrans (nutmeg) are widely used as antioxidants, antidiabetic agents and for the prevention and treatment of different human diseases such as cancer, cardiovascular diseases and bacterial and viral infections. The aim of the study is to determine the antimicrobial activity and in vitro cytotoxicity of essential oil of nutmeg on normal cell line (Vero cell line). The Minimum Inhibitory Concentration (MIC) of the antimicrobial activity was determined using tetrazolium microplate assay. Eight gram negative and 2 g positive species of test microorganism were selected to determine the MIC exhibited by the essential oil. Cytotoxicity assay of the essential oil against normal cell line was conducted using Vero cell line. The percentage of inhibition was calculated and expressed as IC50. Essential oil exhibited variant antimicrobial activity against the tested strains. The MIC values of nutmeg oil ranged from 0.031 to 1 mg mL-1 and showed higher activity against Shigella dysenteriae with MIC value of 0.031 mg mL-1. The nutmeg oil possessed low cytotoxicity against Vero cell line with IC50 at 24.83 μg mL-1. Nutmeg essential oil exhibited strong antibacterial activity against the Shigella dysenteriae with low cytotoxic effects. Thus, the essential oil can be further studied on its action of mechanism and fractionation will be carried out to determine the strength of its antibacterial activity.