Effects of Biocompounds from Brazilian Plants on Mutans Virulence Factors

Objective: To investigate and to compare the influence of some biocompounds isolated from Brazilian plants, such as Mikania spp. and Rheedia brasiliensis, on glucosyltransferase B and F-ATPase enzymes of Streptococcus mutans. Materials and methods: Cupressenic, diterpenic and kaurenoic acids (500 µg/ml) were obtained from hexane fractions of M. laevigata and M. glomerata leaves. 7-epiclusianone (12.5-100 µg/ml) was obtained from peel hexane extract of R. brasiliensis fruits. For glucosyltransferase B (GTF B) assay, the test compounds were added to the purified enzyme in solution or adsorbed onto surface and were incubated (37 ºC, 4 h) in a sucrose substratum (glucose [¹⁴C]). The effect of compounds on GTF B activity was measured by the incorporation of [¹⁴C] glucose from labeled sucrose into glucans. F-ATPase assay was performed using permeabilized cells of S. mutans UA159 and the activity of enzyme was measured in terms of the release of phosphate in reaction. Results: All compounds obtained from Mikania genus reduced the activity of GTF B in solution (50-60% inhibition) and on surface (50-80% inhibition), and the kaurenoic acid displayed the most potent inhibition of GTF B activity in both solution and surface-adsorbed enzyme (60% and 80%, respectively). 7-epiclusianone inhibited 91% of GTF B activity in solution and 48% on surface at the higher concentration tested. F-ATPase activity was inhibited by Mikania compounds tested in 28-40%, whereas 7-epiclusianone inhibited 61% at 100µg/mL. When all results were compared, we observed that Mikania compounds and 7-epiclusianone presented similar results in the control of these two virulence factors of mutans streptococci, although 7-epiclusianone was used at low concentration. Conclusion: The biocompounds from Mikania spp. and Rheedia tested were capable of acting against GTF B and F-ATPase enzymes of S. mutans; however, 7-epiclusianone had the highest potential of inhibition of these two virulence factors of mutans streptococci. (FAPESP#05/57217-5and#06/56379-4; CNPq#304803/2005-7).