Determination of Minimum Inhibitory Concentration (MIC) and percentage Bacterial Growth Inhibition of essential oils against Gram Positive Bacterial pathogens

Essential oils and volatile constituents extracted from Aromatic plants are frequently used in folk medicine for prevention and treatment of different human diseases. The urge to develop alternative treatment strategies follows three different directions. In the present study, an attempt has been planned to determine the Minimum Inhibitory Concentration (MIC) and Percentage Growth Inhibition of Essential oils against two Gram positive bacterial pathogens, Staphylococcus aureus and Bacillus subtilis. The Essential oils selected for the present study was collected from Sidha Medicine Shop, Tirupattur, Vellore district, Tamil Nadu, India. The Broth dilution method was used for the determination of Minimum Inhibitory Concentration (MIC) of Essential oils. The Minimum Inhibitory Concentration (MIC) studies were conducted by using various concentrations of Essential oils viz., 25 µl/ml, 50 µl/ml, 75 µl/ml and 100 µ/ml. The Essential oils exhibits inhibitory activity against Gram positive bacteria in all the concentrations. Among the seven Essential oils tested, Mahualongif oil has showed maximum percentage bacterial growth inhibition when compared to other Essential oils. The inhibitory activity of Mahualongif oil was observed more in Staphylococcus aureus when compared to Bacillus subtilis. For Staphylococcus aureus, lowest inhibitory percentage was noticed in Pungam oil and for Bacillus subtilis lowest inhibitory percentage was noticed in Coconut oil. Keywords: Essential oils, Minimum inhibitory concentration (MIC), Percentage bacterial growth inhibition, Bacillus subtilis and Staphylococcus aureus.