In vitro antimicrobial effects of crude miswake extracts on oral pathogens

ABSTRACT

In vitro, epidemiological and clinical studies have demonstrated beneficial effects of chewing sticks on oral hygiene. The aim of this study was to assess under standardized test conditions whether miswak crude extracts prepared from S. persica roots and twigs using different solvents inhibited in vitro growth of some selected oral microbes involved in infections in humans. Sterile distilled water, 96% ethanol, 2% acetic acid and ethyl acetate were used as solvents. Reference strains of Streptococcus mutans, Lactobacillus acidophilus, Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, Porphyromonas gingivalis, Prevotella intermedia, and Candida albicans were tested for susceptibility to the antimicrobial effects of crude extracts using the broth microdilution method of Cai et al. Microbial growth was estimated spectrophotometrically at 650 nm In 96-well microtiter plates. Different concentrations of the S. persica extracts were Incubated at 37 C with each test strain for up to 72 hrs. The minimum inhibitory concentration [MIC] of the extracts against the Individual test organisms was determined as the lowest concentration of the extract that limited turbidity to <0.05 absorbance at OD650nm Results showed that the root-ethanolic extract was the most potent. The most susceptible strain was S. mutans whereas L. acidophilus was the least susceptible. MIC values for the various plant extracts ranged from 100mg/mi to 300 mg/mi. Based on these results, it was concluded that miswak extracts exhibited low antimicrobial activity against the test microorganisms when compared with 0.2% aqueous chlorhexidine