Antimicrobial Activity of Plant Species From a Brazilian Hotspot for Conservation Priority

Abstract

Serra do Cipó is part of a Brazilian bioma recently qualified as a “hotspot for conservation priority,” an area featuring exceptional concentrations of endemic species and experiencing exceptional loss of habitat. The in vitro antimicrobial activity of 20 plant species occurring in this habitat was evaluated against 4 bacteria and 2 fungal strains. About 75% of the species were active against at least one microorganism. None of the species inhibited the growing of Pseudomonas aeruginosa, Escherichia coli and Saccharomyces cerevisae. The activities of Lavoisiera cordata and Xyris pilosa extracts against Staphylococcus aureus were comparable to that of the pure antibiotic used as a positive control. The preliminary toxicity of the active extracts was evaluated by the brine shrimp lethality test and only three plants showed LD 50 values greater than 1000µg/ml, suggesting that they are relatively non-toxic. Some of the assayed plants are endangered species, presenting different degrees of extinction risk. According to our data, the plant activity against more than one microorganism seems to be advantageous to the evaluated species in protecting them against extinction.