Comparative study of the effect of green and roasted water extracts of mate (Ilex paraguariensis) on glucosyltransferase activity of Streptococcus mutans

Glucosyltransferase (GTF) plays an important role in the development of dental caries. This study was carried out to compare the efficiency of green mate (GM) and roasted mate (RM) water extracts, drinks rich in polyphenolic compounds consumed in the subtropical region of South America, on the extracellular GTF activity from Streptococcus mutans. The RM extract exhibited a greater inhibitory effect (IC50 of 10 mg/mL) despite presenting lower polyphenolic content. The kinetic analysis showed that there were significant differences (P < 0.05) between the extracts with respect to the values for Km and K-i, whereas the values for V-max were the same, implying the competitive nature of GTF inhibition. GTF activity was also measured using selected polyphenols as inhibitors, and the most effective inhibitors were rutin and caffeoylshikimic acid. The characterization of the extracts by ESI-MS and UPLC-MS showed that the compounds formed during roasting, possibly shikimic acid derivatives and other unindentified compounds formed by the Maillard reaction, appeared to contribute to the inhibition of GTF activity.