Background: Streptococcus mutans and Streptococcus sanguinis are Gram-positive bacteria that cause dental caries. The MurA enzyme is a catalyst in the formation of peptidoglycan in the bacterial cell wall making it ideal as an antibacterial target. Basil (Ocimum americanum) is an edible plant medicine that diverse, very widely spreading, used as herbal for a long time, and it was reported to have pharmacology effect as antibacterial activity. The purpose of this study is to identify antibacterial compounds from O. americanum and analyze their inhibition activity to the 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: The lauric acid has potency as a new natural antibacterial agent through the MurA inhibition in bacterial cell wall biosynthesis.

Background: Streptococcus mutans is one of the bacteria which contributes to biofilm formation and causes dental caries. The inhibition of SrtA, gbpC, and Ag I/II is a promising target to be developed as an antibacterial. Ocimum bacilicum is known to have antibacterial activity. Aim and Objective: The aim of this study is to evaluate the potential nevadensin as antibacterial against S. mutans. Methods: Antibacterial analysis was carried out by disc diffusion and micro-dilution methods and the in-silico study was performed with ligand-protein docking. Results: The result showed that the MIC and MBC values of nevadensin are 900 and 7200 µg/mL, respectively. The binding energy of nevadensin to SrtA, gbpC, and Ag I/II were -4.53, 8.37, -6.12 kcal/mol, respectively. Conclusion: Nevadensin shows moderate activity as an antibacterial against S. mutans. Meanwhile, in silico studies showed it has the same binding strength as chlorhexidine in inhibiting SrtA, whereas to gbpC and Ag I/II, it has a weaker binding affinity. Therefore, nevadensin has the potential as natural antibacterial against S. mutans by inhibiting SrtA.

Background: Streptococcus sanguinis can contribute to tooth demineralization, which can lead to dental caries. Antibiotics used indefinitely to treat dental caries can lead to bacterial resistance. Discovering new antibacterial agents from natural products like Ocimum basilicum will help combat antibiotic resistance. In silico analysis (molecular docking) can help determine the lead compound by studying the molecular interaction between the drug and the target receptor (MurA enzyme and DNA gyrase). It is a potential candidate for antibacterial drug development. Objective: The research objective is to isolate the secondary metabolite of O. basilicum extract that has activity against S. sanguinis through in vitro and in silico analysis. Methods: n-Hexane extract of O. basilicum was purified by combining column chromatography with bioactivity-guided. The in vitro antibacterial activity against S. sanguinis was determined using the disc diffusion and microdilution method, while molecular docking simulation of nevadensin (1) with MurA enzyme and DNA gyrase was performed used PyRx 0.8 program. Results: Nevadensin from O. basilicum was successfully isolated and characterized by spectroscopic methods. This compound showed antibacterial activity against S. sanguinis with MIC and MBC values of 3750 and 15000 μg/mL, respectively. In silico analysis showed that the binding affinity to MurA was -8.5 Kcal/mol, and the binding affinity to DNA gyrase was -6.7 Kcal/mol. The binding of nevadensin-MurA is greater than fosfomycin-MurA. Otherwise, Nevadensin-DNA gyrase has a weaker binding affinity than fluoroquinolone-DNA gyrase and chlorhexidine-DNA gyrase. Conclusion: Nevadensin showed potential as a new natural antibacterial agent by inhibiting the MurA enzyme rather than DNA gyrase.