Antibacterial Potency of Aqueous Plant Extracts against Streptococcus mutans

In this study the inhibition effect of aqueous extracts of nine plants (Coriander, Black Tea, Bitter Fennel, Cubeb, Dry Black Lime, Ginger, Nutmeg, Turmeric and Senna) was tested against Streptococcus mutans, which obtained from Dental caries patient; the results showed that the antibacterial effect of these extracts was better in case of adding the extract to the medium than the case of evaporating the extract and then adding it to the medium except in case of Black tea and Nutmeg (was better in case two than in case one). The results of the well diffusion test indicated that crude aqueous extracts of plants under study showed different degrees in inhibiting bacterial growth. The aqueous extract of Black dry lime showed the broadest antibacterial activity by inhibiting growth of tested isolate and at both cases, followed it Black tea and Cubeb. While the aqueous extract of Nutmeg, showed moderate antibacterial activity against the tested bacteria, followed it Ginger, Turmeric and Senna. The aqueous extract of Coriander did not show inhibition activity against S. mutans, while Bitter fennel showed inhibiting growth of S. mutans in case two at concentration 5000μg/ml. The MIC was determined for all extracts against tested bacteria, where the lowest value of MIC was for Black dry Lime and the highest value was for Cubeb, Ginger and Turmeric.