Research Article Polyphenol-Rich Extract from Propolis Reduces the Expression and Activity of Streptococcus mutans Glucosyltransferases at Subinhibitory Concentrations Jorge Jesús Veloz, 1,2 Nicolás Saavedra, 1 Marysol Alvear, 3 Tomás Zambrano, 1 Leticia Barrientos, 1 and Luis A. Salazar 1 1 Center of Molecular Biology and Pharmacogenetics, Scientifc and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Avenida Francisco Salazar 01145, 4811230 Temuco, Chile 2 Departamento de Ciencias Biol´ ogicas y Qu´ ımicas, Facultad de Ciencias, Universidad San Sebasti´ an, Campus Los Leones, Lota 2465, 7510157 Providencia, Santiago, Chile 3 Departamento de Ciencias Qu´ ımicas y Recursos Naturales, Facultad de Ingenier´ ıa y Ciencias, Universidad de La Frontera, Avenida Francisco Salazar, 01145 Temuco, Chile Correspondence should be addressed to Luis A. Salazar; luis.salazar@ufrontera.cl Received 10 December 2015; Accepted 8 March 2016 Academic Editor: Kimon A. Karatzas Copyright © 2016 Jorge Jes´ us Veloz et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tooth decay is an infectious disease, whose main causative agent identifed is Streptococcus mutans (S. mutans). Diverse treatments have been used to eradicate this microorganism, including propolis. To date, it has been shown that polyphenols from Chilean propolis inhibit S. mutans growth and bioflm formation. However, the molecular mechanisms underlying this process are unclear. In the present study, we assessed the efect of Chilean propolis on the expression and activity of the glycosyltransferases enzymes and their related genes. Polyphenol-rich extract from propolis inhibited gene expression of glycosyltransferases (GtfB, GtfC, and GtfD) and their related regulatory genes, for example, VicK, VicR, and CcpA. Moreover, the treatment inhibited glucosyltransferases activity measured by the formation of sucrose-derived glucans. Additionally, an inhibitory efect was observed in the expression of SpaP involved in sucrose-independent virulence of S. mutans. In summary, our results suggest that Chilean propolis has a dose-dependent efect on the inhibition of genes involved in S. mutans virulence and adherence through the inhibition of glucosyltransferases, showing an anticariogenic potential of polyphenols from propolis beyond S. mutans growth inhibition. 1. Introduction Streptococcus mutans (S. mutans) is considered to be the principal causative agent of human dental caries among a wide variety of microorganisms detected in the oral cavity [1, 2]. Although the etiology and factors related to dental caries development are well known, this pathology remains a public health issue due to its increased prevalence in recent reports [3]. Terefore, the search for new therapeutic strategies holds great interest. Polyphenols from diferent botanical sources have emerged as promissory therapeutic agents due to their wide range of biological activities [4]. Propolis is a resinous substance collected by bees (Apis mellifera) from diferent vegetable species [5]. Several pharmacological properties have been described for the extracts of propo- lis, such as antidiabetogenic, antiatherogenic, antimicrobial, and antifungal properties, which are related mainly to the polyphenols content of propolis samples [6–9]. Since chem- ical studies have determined a relationship between propolis composition and the region from where propolis is collected together with the plant source of each area [10, 11], the bio- logical activities of propolis can vary depending on the same conditions aforementioned. We have previously reported antimicrobial activity of Chilean propolis for S. mutans [7] Hindawi Publishing Corporation BioMed Research International Volume 2016, Article ID 4302706, 7 pages http://dx.doi.org/10.1155/2016/4302706