Herbal Antimicrobials under the Lens: In Vitro Assessment of Ocimum basilicum and Glycyrrhiza glabra against Pathogenic Bacteria

Aims: This study was designed to test the antibacterial activity of Ocimum basilicum (Sweet basil) and Glycyrrhiza glabra (Licorice) extracts in four different solvents i.e. petroleum ether, chloroform, methanol and water against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Salmonella typhi. Methodology: Each plant material was weighed and 20.0 grams of it was taken in four different bottles 500.0 mL of each solvent was added in the respective bottle. The extracts were filtered by whatmann’s filter paper, dried in vacuum desiccators and the powder mass obtained was weighed and then reconstituted in respective solvent to get the final extract of known concentrations. Bacteria were inoculated separately in the Nutrient Agar medium in a concentration of 106 CFU/ml and the media was poured in petri dishes and was allowed to solidify. Six wells of 1.0 centimeter diameter were cut in each plate with the help of sterile cork borer. In three wells equal volume of known concentrations of plant extracts was poured with the help of micropipettes. In 4th well, penicillin G (1600µg per well) and in the 5th well Gentamicin (1000µg per well) was taken as a positive control. In the 6th well, respective solvent was taken as a negative control. The plates were incubated at 37 degree Celsius for 24 hours and the DIZ was calculated in millimeters. Each experiment was performed in five replicates. Results and Discussion: Both plant extracts showed considerable activity against gram positive and gram negative bacteria. Ocimum basilicum non-polar components had good activity against gram positive than gram negative bacteria while Glycyrrhiza glabra methanol extract showed greater activity against all tested bacteria. Conclusion: It was concluded that the extracts of both Ocimum basilicum (Sweet Basil) and Glycyrrhiza glabra (Licorice) in petroleum ether, chloroform, methanol and water have antibacterial properties except aqueous extract of Ocimum basilicum.