RESUMO
The essential oils (EOs) chemical composition can be affected by several environmental factors, impacting their desired biological activities. In this sense, this work aimed to evaluate the seasonal variation of the chemical composition and antimicrobial activity of Piper caldense and Piper xylosteoides leaves EOs. Their chemical composition was determined by GC/MS and GC-FID analyses, resulting in the identification of eighty compounds. P.â caldense EOs were mainly consisted of sesquiterpene hydrocarbons, whereas in P.â xylosteoides EOs, monoterpene hydrocarbons were predominant. EOs from both species strongly inhibited B.â subtilis (MIC=0.25â mg mL-1 ), while only P.â caldense EOs showed strong activity against S.â aureus (MIC=0.50â mg mL-1 ). P.â caldense spring EO showed the broadest spectrum of antimicrobial action amongst all samples. For each species, PCA seasonally differentiated EOs chemical composition. In addition, as expected, PCA of all samples showed a distinction between the two species. This study has successfully demonstrated the importance of evaluating the seasonal variation of EOs chemical composition and antimicrobial activity in obtaining a product with the desired properties.