Acmella paniculata, also known as ’Subang nenek’ in Malaysia, has been used to treat diseases such as toothache and gum infections. People called it a toothache plant, and it has been widely used as traditional medicine. Therefore, this study aims to investigate the antibacterial activities of A. paniculata leaves and flowers extracts towards Streptococcus mutans by using disc diffusion assay, minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) methods. Besides, the anti-biofilm activity of all the extracts also been determined by using a crystal violet assay. As the results, n-hexane and methanol extracts from leaves showed the highest inhibition zone towards S. mutans when compared to DCM and acetone extracts. Meanwhile, for the flowers extract, n-hexane and DCM showed the highest inhibition zone towards S. mutans compared to methanol and acetone extracts. The best results were then tested for MIC and MBC tests. As for the MIC values of n-hexane and methanol leaves extracts were 25 mg/mL, respectively, and the MBC values were 50 and 100 mg/mL, respectively. Whereas MIC values for n-hexane and DCM flowers extracts were 12.5 mg/mL, respectively, and the MBC values were 50 mg/mL, respectively. Biofilm formation of S. mutans showed decrement up to 70% after exposure to both leaves extract (n-hexane and methanol) and n-hexane flower extract. Still, it differed when exposing to DCM flower extract, and the result showed that the biofilm activities of S. mutans were inhibited at 80% after treated with DCM flowers extracts. In conclusion, n-hexane leaves extract, methanol leaves extract, n-hexane flowers extract, and DCM flowers extract of A. paniculata demonstrated bactericidal properties against S. mutans. © International Journal of Research in Pharmaceutical Sciences.

The aim of this study was to isolate lactic acid bacteria (LAB) from fermented food, to determine its antibacterial activity, and to identify the LAB in order to select candidate probiotic strains for preventing caries. The probiotic strains were isolated from eight fermented food which are tapai ubi, tapai pulut, rebung, tauchu, kimchi, cincalok, tempeh and tempoyak, taucu. Ten-fold serial dilutions of the fermented food samples were made in sterile peptone water before plating on de Man Rogosa and Sharpe (MRS) agar. The pure cultures were then randomly picked and biochemically identified. Then, the antibacterial activity of LAB against Streptococcus mutans was assessed by using the disk diffusion method. A total of 120 LAB were isolated from eight different fermented foods. The morphologies of the isolates were circular, convex, dull opaque white or translucent white. Gram staining identification showed that the isolates were Gram-positive rods. Of the 120 LAB isolates, five strains displayed moderate to strong antibacterial activity against S. mutans with the inhibition zones ranging from 7-12 mm. The antibacterial activity demonstrated from LAB isolated from fermented foods suggests that the isolates from fermented foods possess antibacterial properties against a pathogen which responsible for causing dental caries. These strains are currently investigated in depth to assess whether they can be fully characterized as probiotics. 2020