Seasonal and Regional Variation of the Chemical Composition and Antimicrobial Activity of Essential Oils From Piper marginatum Jacq.

ABSTRACT Essential oils (EO) from Piper marginatum Jacq. exhibit biological activities dependent on chemical compositions, which vary mainly due to environmental factors. This study investigated the seasonal and regional variation in the chemical composition and antimicrobial activity of EO from P. marginatum leaves collected in three Brazilian regions across four seasons. Sixty compounds were identified, primarily terpenoids and phenylpropanoids. Multivariate analyses revealed seasonal variations and distinguished the Northeast region EO, which contained the isomers pipermargine (3.38%–14.56%) and 1,3,5‐trimethoxy‐2‐[( Z )‐prop‐1‐enyl]benzene (13.47%–14.87%)—reported for the first time in EO. The Central‐West winter EO exhibited the broadest antimicrobial spectrum, with strong activity against Candida albicans (MIC 0.5 mg mL −1 ) and Bacillus subtilis (MIC 0.5 mg mL −1 ), and a bacteriostatic effect against Staphylococcus aureus . All EO inhibited Escherichia coli , with the Northeast winter EO showing the strongest activity (MIC 0.25 mg mL −1 ). This work highlights the importance of studying the chemical and biological variability of P. marginatum EO for potential applications.