Antibacterial Activity of , , , and and their mechanism of action against .

BACKGROUND

Curative plants have reportedly been used to make chewing sticks/toothbrushes intended for the treatment of oral diseases.

OBJECTIVE

The antibacterial activities of , , , and were evaluated against , along with the cytotoxicity and antioxidant and synergistic potentials. The effect of on the expression of crucial virulence genes and of S. mutans was determined.

MATERIALS AND METHODS

The antibacterial activity was determined using a modified microdilution method. The antioxidant potential was evaluated using diphenyl picrylhydrazyl (DPPH), Griess reagent, and nitroblue tetrazolium calorimetric assays. The synergistic activity was investigated using a modified checkerboard method, while the cytotoxicity was determined according to a cell proliferation 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Reverse transcription was the chosen method for determining the difference in expression of the and genes after treatment with the plant sample.

RESULTS

and had the highest antibacterial activity at concentrations of 0.3 mg/ml and 6.25 mg/ml, respectively. had the best free radical scavenging of DPPH, exhibiting 50% inhibition at 28.72 μg/ml; while showed better superoxide scavenging potential than the positive control quercetin. Both and had adequate activity against the nitric oxide-free radical (12.87 and 18.89 μg/ml, respectively). selectively reduced the expression of the gene, indicating a mechanism involving Glucotranferases, specifically targeting bacterial attachment.

SUMMARY

and had very good antibacterial activity against and moderate toxicity against Vero cells had the best antioxidant capacity overall reduced the expression of gene at 0.5 mg/ml. : AA: Ascorbic acid; BHI: Brain-heart infusion; CHX: Chlorhexidine; DPPH: Diphenyl picrylhydrazyl; DMSO: Dimethlysulfoxide; NBT: Nitroblue tetrazolium; NO: Nitric oxide.