濃度、溫度、pH與菌齡影響蜂膠乙醇萃出物對Streptococcus mutans之抗菌活性   全文下載

Antibacterial Activity of Propolis Ethanol Extract Against Streptococcus mutans as Influenced by Concentration, Temperature, pH and Cell Age

本研究先將蜂膠以80%酒精萃取，然後測試濃度、溫度、菌齡、pH影響蜂膠酒精萃出液（EEP）對Streptococcus mutans（一種會引起齲齒之口腔病原菌）之抗菌活性。結果顯示EEP在1.875&3.95μg/mL劑量下即能對所試之Str. mutans呈現靜菌及殺菌效果。EEP在37℃下對Str. mutans所表現之抗菌效果明顯優於4℃及25℃者。Str. mutans對EEP敏感性於酸性pH值時最高，中性pH居次而於鹼性pH下則最低。菌齡會影響Str. mutans對EEP之敏感性。其敏感性之高低依序為對數期中期、對數期末期及定常期之菌體。曝露於EEP後，菌種懸浮液之離心上層液顯著地提高其對260 nm之吸光值（UV-吸收物質）。此外掃描式電子顯微鏡顯示在EEP處理之菌體週圍增加許多不規則之物質。

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 cavitycausing 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.