Antimicrobial activity from Semi-arid plants (Brazil) on mutans streptococci

Objectives: The aim of the present study was to analyze in vitro the antimicrobial properties of plants from the Nacional Forest of Contendas do Sincorá (Bahia) against mutans streptococci. Methods: The ethanolic extracts (100% v/v) from the leaves of pata de cabra (Leguminoseae cesalpinaceas), juá (Zizyphus joazeiro), peroba (Aspidospherma australe M.Arg.- Apocynaceae); bark of escada de macaco (Bauhinia sp.), peroba (Aspidospherma australe), pau d'arco (Tabebuia impetiginosa), umbu (Spondios Tuberosa Arruda), and branch of canela de velho (Miconia albicans Stewd.), and tested concentration ranging from 1000 to 31,25 μg/mL. Minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) values of ethanolic extracts against Streptococcus mutans UA159, S. sobrinus 6715 and S. mutans Ingbritt 1600 were determined. And also, the inhibition of the adherence (Adh) of growing cells of S. mutans UA159, S. sobrinus 6715 and S. mutans Ingbritt 1600 on surface was measured spectrophotometrically. The plaques were incubated at 5% CO2, 37 0C for 18h, and three replicates were realized. Negative control was ethanol 100% (v/v), with final volume less than 10%. Results: The most expressive values of antimicrobial activity were obtained for S. mutans 1600 for canela de velho extracts (MIC 62.50 μg/mL, MBC 125 μg/mL), pau d'arco extracts (MIC 250 μg/mL, MBC 500 μg/mL) and escada de macaco (MIC 500 μg/mL, MBC 500 μg/mL). For S. mutans UA159, the extracts of canela de velho (MIC 125 μg/mL, MBC 250 μg/mL), and pau d'arco (MIC 125 μg/mL e MBC 500). And to S. sobrinus 6715 canela de velho extracts (CIM 500 μg/mL e CBM 1000 μg/mL). For ADH test, canela de velho extract (500 μg/mL) inhibited the adherence of mutans streptococci. Conclusions: the extracts of canela de velho, pau d'arco, escada de macaco and juá have antimicrobial activity and are promising new sources to isolated new bioative compounds. CAPES, FAPESB, CNPq.