Antibacterial actvity and synergistic effect investigation of terpenoids from Copaifera langsdorffii Desf. against cariogenic bacteria
In the present work, the anticariogenic activities of nine labdane type-diterpenes and four sesquiterpenes were investigated (Figure). Among these metabolites, (–)- copalic acid (2) was the most active compound displaying very promising MIC values (ranging from 2.0 to 6.0µg mL-1) against the main microorganisms responsible for dental caries: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis and Lactobacillus casei . Due to its highest anticariogenic activity, the synergistic effect of 2 combined with the anticariogenic gold standard (chlorhexidine, CHD) was investigated in the checkerboard assays  against the most important cariogenic microorganism (S. mutans). No synergistic effect was observed but the MIC values obtained allow us to conclude that 2 is an important metabolite in the search for new effective anticariogenic agents.
Acknowledgements: FAPESP (Proc. 2009/09438–3)
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