Antimicrobial activity of fractions of Anadenanthera macrocarpa on mutans streptococci

Objectives: The aim of the present study was to analyze in vitro the antimicrobial properties of ethanolic extracts of angico (Anadenanthera macrocarpa) collected on the Nacional Forest of Contendas do Sincorá (Brazil), against mutans streptococci. Methods: Ethanolic extracts (100% v/v) and fractions (ethyl acetate, butanol, hexane, dichloromethane) were obtained from the bark, leaves and branch of Angico (Anadenanthera macrocarpa) and prepared two-fold dilution series with final concentration ranging from 1000 to 31,25 μg/mL. Minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) values of ethanolic extracts and fractions against Streptococcus mutans UA159 and S. sobrinus 6715 were determined. And also, the inhibition of the adherence (Adh) of growing cells of S. mutans UA159 on surface was measured spectrophotometrically. For the tests, the plaques were incubated at 5% CO2, 37 0C for 18h. Three replicates were realized for all tests. Negative control was ethanol 100% (v/v), with final volume less than 10%. Results: The most expressive values of antimicrobial activity were obtained from the bark extract for Streptococcus mutans UA159 (MIC 250 μg/mL) and ethyl acetate bark fraction (MIC 62.50 μg/mL, MBC 500 μg/mL), ethyl acetate leave fraction (MIC 125 μg/mL, MBC 1000 μg/mL) and ethyl acetate branch fraction (MIC 500 μg/mL, MBC 1000 μg/mL). For S. sobrinus, ethyl acetate leave and branch showed MIC 500 μg/mL. For the test of ADH, angico bark extracts (250 μg/mL) inhibited the adherence of Streptococcus mutans UA159. Conclusions: The ethanolic extracts of bark and the ethyl acetate fractions of Angico showed the most expressive results of antimicrobial activity. The fractions of these plants will be studied to identify the bioative compounds. CAPES, FAPESB, CNPq.