Objective: Stelechocarpus burahol is one of the native plants of Indonesia that has been used as an oral deodorant. This fruit contains flavonoids, which flavonoids are known to have antimicrobial activity against oral bacteria. The purpose of this study was to demonstrate the ethyl acetate fraction of S. burahol fruit to inhibit growth of oral bacteria and determine it the total flavonoid content. Methods: Antimicrobial activity test was performed againt oral bacteria (Porphyromonas gingivalis and Fusobacterium nucleatum) by disc diffusion and microdilution methods. The diffusion assay used Brucella Blood Agar (BBA) plate with paper disks soaked in the fraction of ethyl acetate S. burahol with various concentration (1,2,4,8,10,20,40, and 60% w/v), the inhibitory zone diameter of each bacteria compared to standard catechins. The minimum inhibition concentration value (MIC) was using the microdilution method with brucella broth for bacterial growth medium. Total flavonoid content was measured by UV/Visible spectrophotometer with standard quercetin at 440 nm wavelength. Results: The results showed that ethyl acetate fraction could inhibit the growth of P. gingivalis and F. nucleatum with concentration of 1% w/v, and the MIC was 125 ug/ml. The total flavonoid content is 0.833 extract mg/g Quercetin Equivalent. Conclusion: The ethyl acetate fraction of S. burahol fruit contained flavonoid that can be used as antimicrobial against oral bacteria.
Key words: Antimicrobial, Total flavonoid content, Oral bacteria, Stelechocarpus burahol, Ethyl acetate fraction.