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 1000 mg/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.

Antimicrobial activity of Trembleya laniflora , Xyris platystachia and Xyris pterygoblephara

“…In the previous work (Cota et al, 2002), the extracts from T. lanifl ora stems and X. pterygoblephara aerial parts were active against S. aureus, while X. platystachia did not show inhibitory effect against this microorganism. Such contradictory results may be explained by differences in extract compositions, since the plant materials were collected in distinct locations.…”

“…The ethanol extracts of Trembleya lanifl ora, Xyris platystachia and Xyris pterygoblephara have been previously evaluated in antimicrobial assays, against different strains of bacteria and fungi (Cota et al, 2002;Cota et al, 2004). The three species were particularly active against S. aureus and M. luteus, and for this reason both were selected as test organism in the present work.…”

“…Recently, we reported the isolation of a new anthraquinone from X. pilosa, active against Fusarium oxysporum (Cota et al, 2004). Except the antimicrobial effect (Cota et al, 2002;Cota et al, 2004), no other biological activity or any chemical data has been described for X. platystachia and X. pterygoblephara, species selected for the study.…”

“…The area presents exceptional concentrations of endemic species and is experiencing loss of habitats, contributing to drive many species into extinction. We have previously investigated the antifungal and antibacterial activity of 20 plant species from Serra do Cipó (Cota et al, 2002). Among the active species, three were selected for study in the present work.…”

“…A chemotaxonomic study carried out for the leaves of Melastomataceae species, belonging to the closely related genera Lavoisiera, Microlicia and Trembleya, resulted in the identifi cation of 116 fl avonoids, comprising 69 fl avonol and 47 fl avone glycosides, including kaempferol 3-O-glycosides and quercetin 3-O-glycosides in T. lanifl ora (Bomfi m-Patrício et al, 2001). A literature search indicated no ethnomedical use or biological activity other than antimicrobial described for T. lanifl ora (Cota et al, 2002). Xyris species are small shrubs, popularly known as "sempre-vivas" (everlasting plants).…”