Background: Streptococcus mutans and Streptococcus sanguinis are Gram-positive
bacteria that cause dental caries. MurA enzyme acts as a catalyst in the formation of peptidoglycan
in bacterial cell walls, making it ideal as an antibacterial target. Basil (Ocimum americanum)
is an edible plant that is diverse and has been used as a herbal medicine for a long time. It has
been reported that basil has a pharmacological effect as well as antibacterial activity. The purpose
of this study was to identify antibacterial compounds in O. americanum and analyze their inhibition
activity on MurA enzyme.
Methods: Fresh leaves from O. americanum were extracted with n-hexane and purified
by a combination of column chromatography on normal and reverse phases together
with in vitro bioactivity assay against S. mutans ATCC 25175 and S. sanguinis ATCC
10556, respectively, while in silico molecular docking simulation of lauric acid (1) was
conducted using PyRx 0.8.
Results: The structure determination of antibacterial compound by spectroscopic methods
resulted in an active compound lauric acid (1). The in vitro evaluation of antibacterial activity in
compound 1 showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal
Concentration (MBC) values of 78.13 and 156.3 ppm and 1250 and 2500 ppm against S.
sanguinis and S. mutans, respectively. Further analysis and in silico evaluation determined lauric
acid (1) as MurA Enzyme inhibitor. Lauric acid (1) showed a binding affinity of -5.2 Kcal/mol,
which was higher than fosfomycin.
Conclusion: Lauric acid showed the potential as a new natural antibacterial agent through MurA
inhibition in bacterial cell wall biosynthesis.