A busca de novos medicamentos eficases para o combate das infecÃÃes por bactÃrias multiresistentes à uma das grandes preocupaÃÃes da Ãrea cientÃfica mundial, desde o relato de existÃncia de cepas resistentes a penicilina observada por Kirby em 1966. A preocupaÃÃo à crescente devido à disseminaÃÃo destas estirpes resistentes, tanto em ambito ambulatorial quanto hospitalar e a diminuiÃÃo de registro nos Ãltimos anos de novas drogas com potencial de controle das infecÃÃes. No intuito de contribuir com o desenvolvimento de novos fÃrmacos atravÃs de isolamento de molÃculas provenientes de plantas com potencial antimicrobiano, foi proposto o screening dos extratos hexÃnicos, alcoÃlicos 95ÂGL e a 70% de seis plantas - Jenipapo (Genipa americana L.), - Folha da Fortuna (Bryophyllum pinnatum (Lam.) Oken), - Meracilina (Alternanthera cf. brasiliana (L.) Kuntze), - Mangabeira (Lafoensia pacari St. Hil), - Mesocarpo do BabaÃu (Orbignya spp.), - Bacuri (Attalea phalerata Mart.); contra oito estirpes de bactÃrias, cinco Gram-positivas e trÃs Gram-negativas. Os referidos extratos secos de cada planta foram obtidos por masceraÃÃo, seguido de evaporaÃÃo do solvente e liofilizaÃÃo. Estes extratos foram solubilizados em DMSO:H20 â 1:1 atà concentraÃÃes que variaram de 1000 a 1mg/mL para avaliaÃÃo microbiolÃgica, pela tÃcnica de difusÃo em agar, com deposito de 50ÂL do extrato em poÃos de 6x8mm. As bactÃrias ensaiadas demonstraram-se resistentes a todos os extratos hexÃnicos das plantas experimentadas, alÃm dos extratos alcoÃlicos das folhas de A. brasiliana. Os extratos alcoÃlicos 95ÂGL e 70% de folhas de L. pacari e folhas de B. pinnatum inibiram o crescimento de todas as espÃcies de bactÃrias apresentando halos de inibiÃÃo superiores a 15mm e concentraÃÃo mÃnima inibitÃria - CMI entre 250 a 1mg/mL. Os extratos alcoÃlicos 95ÂGL e 70% Mesocarpo de Orbignya spp inibiu o crescimento de bactÃrias gram positivas, com halos de inibiÃÃo maiores que 10 mm e menores de 20 mm e CMI entre 250 a 100mg/mL. Jà o fruto de G. americana e o mesocarpo e epicarpo de A. phalerata inibiram tanto bactÃrias gram positivas como Gram negativas, mas com resistÃncia a vÃrias estirpes para os extratos alcoÃlicos 95ÂGL e 70% com halos de inibiÃÃo superior a 10mm e inferor a 20mm e CMI de 1000 a 500mg/mL. Os resultados da entrecasca da G. americana obtiveram halos de inibiÃÃo entre 10 e 15mm com CMI variando entre 1000 a 250 mg/mL. Posteriorente, o extrato alcoÃlico 70% do Mesocarpo de Orbignya spp foi submetido fracionamento bioguiado por tÃcnicas quÃmicas, cromatograficas e Bioautografia, obtendo 24 fraÃÃes com potencial para atividade antimicrobiana. Assim, a maioria dos extratos ensaiados mostrou-se eficazes contra microrganismos patogÃnicos, compreendendo ser uma fonte promissora de fÃrmacos antimicrobianos. / The research for new drugs efficient to combat of multiresistant bacteria infections is a great concern of the scientific world, since the report of the existence of strains resistant to penicillin followed by Kirby in 1966. Because to spread of resistant strains in hospital and outpatient and lessen records in recent years of new drugs with potential for control these infections. Thought to contribute to development of new drugs and isolament of molecules from plants with antimicrobial potential, was proposed screening of the hexane extract, 95  GL alcohol and 70% of six plants - Jenipapo (Genipa americana L.), -Folha da Fortuna (Bryophyllum pinnatum (Lam.) Oken), -Meracilina (Alternanthera cf. brasiliana (L.) Kuntze ), -Mangabeira (Lafoensia pacari St. Hil), - Mesocarpo do BabaÃu (Orbignya spp.), - Bacuri (Attalea phalerata Mart.); against eight strains of bacteria, five Gram-positive and three Gram-negative strains. All dried extracts of each plant were obtained by masceraÃÃo, followed by evaporation of the solvent and lyophilization. These extracts were solubilized in DMSO: H20 - 1:1 up to concentrations ranging from 1000 to 1mg/ml for microbiological evaluation, the technique of diffusion in agar, with deposit of 50μL of extract in wells of 6x8mm.The bacterias tested showed resistant for hexane extract of all plants, and addition of alcoholic extracts of leaves of A. brasiliana. The extracts alcoholic 95ÂGL and 70% of leaves of L. pacari and leaves of B. pinnatum inhibited growth of all species of bacterias, and showing halos of inhibition greater than 15mm and minimum inhibitory concentration - MIC of 250 to 1mg/ml. The alcoholic extracts and 95ÂGL 70% of mesocarp Orbignya spp inhibited the growth of gram positive bacteria, with halos of inhibition larger than 10 mm and less than 20 mm and MIC of 250 to 100mg/mL. The alcohol extracts 95ÂGL and 70% of G. americana fruit and the A. phalerata mesocarp and epicarp inhibited gram positive and gram-negative bacteria, but with resistance to some strains and demonstrate inhibition halos with 10 to 20mm and MIC of 1000 to 500mg/mL. The results of extracts of sap of G. American show inhibition halos between 10 and 15mm with MIC ranging from 1000 to 250 mg/mL. The alcoholic extract 70% form mesocarp of Orbignya spp was fractionated by chemical techniques guided by biological activity, followed by chromatography and bioautography, were obtained 24 fractions with antimicrobial activity potential. Thus, the most of extracts tested showed to be effective against pathogenic microorganisms, comprising a promising source of antimicrobial agents.