Efficacy of E. officinalis on the cariogenic properties of Streptococcus mutans: a novel and alternative approach to suppress quorum-sensing mechanism.

Sadaf Hasan,Kunal Singh,Mohd Danishuddin,Mohd Adil,Asad U Khan,Praveen K Verma,Indranil Biswas

doi:10.1371/journal.pone.0040319

Sadaf Hasan, Kunal Singh + Show 5 more

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https://doi.org/10.1371/journal.pone.0040319

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Abstract

The present study was focused on evaluating the potential of Emblica officinalis against cariogenic properties of Streptococcus mutans, a causative microorganism for caries. The effect of crude extract and ethanolic fraction from Emblica officinalis fruit was analysed against S. mutans. The sub-MIC concentrations of crude and ethanolic fraction of E. officinalis were evaluated for its cariogenic properties such as acid production, biofilm formation, cell-surface hydrophobicity, glucan production, sucrose-dependent and independent adherence. Its effect on biofilm architecture was also investigated with the help of confocal and scanning electron microscopy (SEM). Moreover, expression of genes involved in biofilm formation was also studied by quantitative RT- PCR. This study showed 50% reduction in adherence at concentrations 156 µg/ and 312.5 µg/ml of crude extract and ethanolic fraction respectively. However, the biofilm was reduced to 50% in the presence of crude extract (39.04 µg/ml) and ethanolic fraction (78.08 µg/ml). Furthermore, effective reduction was observed in the glucan synthesis and cell surface hydrophobicity. The qRT-PCR revealed significant suppression of the genes involved in its virulence. Confocal and scanning electron microscopy clearly depicted the obliteration of biofilm structure with reference to control. Hence, this study reveals the potential of E. officinalis fruit extracts as an alternative and complementary medicine for dental caries by inhibiting the virulence factors of Streptococcus mutans.

Highlights

Dental caries is an irreversible localized infection that results in the progressive tooth decay [1]
The key virulence factors include acidogenicity and aciduricity coupled with its ability to produce large amounts of extracellular polysaccharides or glucans which are synthesized from dietary carbohydrates by glucosyltransferases (GTFs)
The major constituents of the crude and ethanolic fractions of E. officinalis were determined by GC- MS

Summary

Introduction

Dental caries is an irreversible localized infection that results in the progressive tooth decay [1]. Streptococcus mutans, a gram positive oral bacterium has been long implicated to be a primary causative agent of this ubiquitous disease [2] This bacterium is known to cause infective endocarditis which may cause significant morbidity and mortality [3]. S. mutans is known to produce at least three forms of GTFs: GTF B, GTF C and GTF D, synthesizing mostly insoluble glucan, mixture of soluble and insoluble glucan and soluble glucan respectively These glucans are essential for the structural formation and establishment of cariogenic plaque [6]. The production of acid by S. mutans and its power to tolerate the acidic pH favours its continual survival and colonization in the dental biofilm [7] These acids begin the dissociation of the tooth enamel leading to localized decalcification, cavity formation and breakdown of calcified dental tissue [8]. This has been the aim of many in vitro studies where different agents including plant extracts and other natural products shown to have these inhibitory features [9]

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