Abstract
<title>Abstract</title> <p> The oral microbiome houses numerous microbial species, including primary initiators of dental caries and oral infections such as <italic>Streptococcus mutans</italic> , etc. Nigerian ethnobotanical plants have been used by herbal practitioners or individuals in the treatment of oral infections but the scientific validation of this practice remains unknown. This study was aimed at undertaking a scientific characterization of some Nigerian ethnobotanical plants for their antimicrobial activities against key oral microbes and determining of the time of kill for these plants. Fifteen Nigerian ethnomedical plant extracts were tested for their antimicrobial effectiveness against oral cavity microbes ( <italic>Candida albicans</italic> , <italic>Streptococcus mutans</italic> , <italic>Lactobacillus fermentum</italic> , <italic>Lactococcus lactis</italic> and <italic>Klebsiella aerogenes</italic> ). Agar well diffusion method was adapted for the antimicrobial assay. The time taken by the plant extracts in inhibiting the growth of the test microorganisms was determined. Seven plants displayed good antimicrobial activity against oral microbes, although the extents to which they inhibited microbial growth differed markedly (p < 0.05). Overall, methanolic extracts presented the most antimicrobial activities. At 35 ± 0.00 mm and 35 ± 0.58 mm zones of inhibition, respectively, neem ( <italic>Azadirachta indica</italic> ) and bitter kola ( <italic>Garcinia kola</italic> ) methanol extracts were most potent against <italic>C. albicans</italic> strains, compared to the corresponding ethanol extracts (33 ± 0.58 mm and 32 ± 0.00 mm). The time of kill of <italic>Dennetia tripetala</italic> essential oil against <italic>L. fermentum</italic> was 24h, while <italic>Olax subscorpioidea</italic> still showed few cells growth after 24h. This study has provided a scientific backing that some Nigerian plants are effective in inhibiting oral microbes and could be useful in preventing dental carries. </p>