Potential fatty acid as antibacterial agent against oral bacteria of Streptococcus mutans and Streptococcus sanguinis from Basil (Ocimum americanum): in vitro and in silico studies.

Abstract

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 extracted with n-hexane and purified by a combination of column chromatography on normal and reverse phase together with guided by 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) using PyRx 0.8. Results: The structure determination of antibacterial compound by spectroscopic methods resulted in an active compound 1 as lauric acid. The in vitro evaluation of antibacterial activity compound 1 showed the MIC and MBC of 78.13 & 156.3 ppm and 1250 & 2500 ppm against S. sanguinis and in S. mutans, respectively. Further analysis in silico evaluation as MurA Enzyme inhibitor, lauric acid (1) has a binding affinity of -5.2 Kcal/mol those higher than fosfomycin. Conclusion: Lauric acid showed the potential as a new natural antibacterial agent through MurA inhibition in bacterial cell wall biosynthesis.