Abstract

Piper aduncum L. (Piperaceae) is a shrub native from Central to South America used in traditional medicine for the treatment of several deseases. The extract of this species stands out for its interesting biological activities as leishmanicidal, molluscicidal, larvicidal, insecticidal, fungicidal, and antibacterial. The aim of this study was to evaluate the antimicrobial activity of essential oil from leaves of P. aduncum and 1,8-cineole, the major component of the oil, against Pseudomonas aeruginosa, Staphylococcus aureus,Staphylococcus epidermidis, Escherichia coli, and Candida albicans. The essential oil was extracted from fresh leaves by hydrodistillation in a modified Clevenger type apparatus and was subjected to analysis by gas chromatography coupled to flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). To evaluate the antimicrobial activity, agar well diffusion method (drop test) and micro broth dilution method were used. Analysis of the essential oil allowed the identification of 23 different substances, including monoterpenes (90.4%) and sesquiterpenes (7.0%). The major component was characterized as 1,8-cineole (53.9%). Quantitation with external standard showed a percentage of 47.0% for 1,8-cineole. The essential oil showed significant antibacterial activity against Gram-positive, S. epidermidis and S. aureus, and against the fungus, C. albicans (MIC 100 µg/ml). However, 1,8-cineole was not active, suggesting that the antimicrobial activity may arise from a synergism of other chemical components of essential oil, mainly the monoterpenes.

Key words: Piper aduncum, Piperaceae, essential oil, antimicrobial activity.