EVALUATION OF ANTIMICROBIAL AND CYTOTOXIC ACTIVITIES OFPLANT EXTRACTS FROM SOUTHERN MINAS GERAIS CERRADO

摘要

The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis (BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carriedout on C6-36 larvae cells of the Aedes albopictus mosquito. Theextracts of stem and flower of Heliconia rostrata, leaf and stem ofPlinia cauliflora, seed of Anonna crassifloraand stem, flower and root of B. pilosa did not present toxicity inthe analyzed concentrations. The highest rates of selectivity appeared in theextracts of stem of A. crassiflora and flower of B.pilosa to Staphylococcus aureus, presenting potentialfor future studies about a new drug development.