A study on anticariogenic properties of some herbal extracts

Abstract

Streptococcus mutans is known as a primary pathogen of dental caries. Glucan synthesis, adherence to tooth surface and biofilm formation is important physiological and virulence factors of S. mutans. The first two studies aimed to evaluate the influence of the crude and active solvent fraction of Trachyspermum ammi and Prosopis spicigera on S. mutans cariogenicity, effect on expression of genes involved in biofilm formation and caries development in rats. The crude extract and the solvent fraction exhibiting least MIC were selected for further experiments. Comparative gene expression analysis was carried out for nine selected genes known to be mostly involved in S. mutans biofilm formation. For the caries study, a total of 50 rats infected with S. mutans were treated topically. Real-time RT-PCR analyses revealed significant shifts in the expression of the genes involved in biofilm formation. The results presented provide new insights at the molecular level regarding gene expression in this bacterium when grown in the presence of plant extracts, allowing a better understanding of the mechanism influencing biofilm formation by S. mutans. All the test groups showed reduction in caries (smooth surface as well as sulcal surface caries) in rats. Furthermore, the data suggests the putative cariostatic properties of these plants. The study further indicates that the petroleum ether fraction of T. ammi and the ethanolic fraction of P. spicigera could be the fractions of choice for identifying further potentially novel anti-caries agents. The objective of the third study was to isolate and characterize the active compound from Trachyspermum ammi seeds, exhibiting antibiofilm activity against Streptococcus mutans. Purification of the active compound from the seeds was performed by silica gel chromatography, and spectroscopic methods (FTIR, NMR and MS) were employed for its identification and structure determination. Antibiofilm and anti-adherence activities of the active compound against S. mutans were analysed.