Article Title

Antibacterial activity of propolis ethanol extract against streptococcus mutans as influenced by concentration, temperature, pH and cell age


In the present study, the ethanol extract of propolis (EEP) collected in Taiwan was prepared and assayed for the effects concentration, incubation temperature, pH and cell age on the antimicrobial activity against Streptococcus mutans, a dental cavity-causing oral pathogen. Additionally, cell leakage of Str. mutans in presence of EEP was also examined. It was found EEP exerted bacteriostatic and bactericidal effects against Str. mutans, respectively, at concentrations of 1.875 and 3.75 μg/mL or more. At 37°C, Str. mutans was more sensitive to EEP than at 25°C while most resistant at 4°C. Cells of test organism were most susceptible to EEP at acid pH followed by neutral and alkaline pH. It was also noted that cells of Str. mutans in the stationary phase were more resistant, while cells in the mid-exponential phase were more susceptible to EEP. After exposure to EEP, a marked increase in the 260 nm absorbance for the supernatant of culture, was observed, indicating the release of UV-absorbing materials. Scanning electron micrographs also showed an increase in material with irregular shape on the surface of EEP-treated Str. mutans cells.

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