RESUMEN
A study was conducted to determine the chemical composition and the antibacterial activity of essential oils from Bocageopsis multiflora (Mart.) R.E. Fr., Ephedranthus amazonicus R.E. Fr., Guatteria blepharophylla Mart. and Xylopia aromatica (Lam.) Mart . The essential oils were obtained from the leaves by hydrodistillation and analyzed by GC-FID and GC-MS. The chromatograms showed the predominance of sesquiterpenoids. Spathulenol was the major constituent of oils of B. inultiflora (20.3%), X aromatica (21.5%) and E. amazonicus (16.9%); followed by caryophyllene oxide of G. blepharophylla (55.7%). Other constituents with significant percentages were the sesquiterpenes P-bisabolene (11.9%) in the samples oil of B. multiflora, humulene epoxide 11 (16.3%) -of E. amazonicus, the monoterpenes trans-pinocarveol (10.2%) and dihydrocarveol (11.6%) of X aromatica. The essential oils of X. aromatica and G. blepharophylla showed strong activity against Gram-positive bacteria Streptococcus sanguinis by microdilution method. The antimicrobial activity against Staphylococcus aureus also was detected by G. blepharophylla essential oil.