Antibacterial activity of plant extracts from caatinga

The Brazilian semi-arid or Caatinga is a biome located almost exclusively in the Northeast region. The local communities demonstrated numerous uses for the plants, although few studies about the pharmacological properties of these species there have been developed. The present study evaluated the anti-Pseudomonas aeruginosa activity of aqueous extracts from Anadenanthera colubrina (Fabaceae, Mimosoideae), Myracrodruon urundeuva (Anacardiaceae), Commiphora leptophloeos (Burseraceae) and Pityrocarpa moniliformis (Fabaceae, Mimosoideae) and characterized some aspects of their mechanism of action. The minimal inhibitory concentration and the effect of the extracts on bacterial growth were determined by counting the colony forming units, as well as by antibacterial activity kinectics. Transmission electron microscopy was used to support the previous results. Phytochemical analysis was performed by TLC, bioautography and HPLC. All extracts showed a bacteriostatic effect under the experimental condition. Polyphenols, flavonoids, anthraquinones, anthrones, coumarins, peptides, terpens, steroids and saponins are the supposed class of compounds involved in the antibacterial activity. The four extracts are possible new sources of antibacterial agents against P. aeruginosa