ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY IN VITRO OF PIPER ADUNCUM ESSENTIAL OIL

Objective: This study aimed to evaluate the antioxidant and antimicrobial activities of Piper aduncum essential oil (EO), as well as characterize its chemical composition. Methods: The EO was extracted via hydrodistillation from fruits collected in Maranhão, Brazil. Antioxidant activity was assessed using the hydroxyl radical scavenging assay, while antimicrobial activity was evaluated against bacterial strains (E. coli, S. aureus, S. enterica, P. aeruginosa, K. pneumoniae, S. pneumoniae, L. monocytogenes, and E. faecalis) via MIC and MBC determination. Chemical composition was analyzed by GC-MS/GC-FID. Results: The EO exhibited high antioxidant activity (IC₅₀ = 24.36 mg/L), though less potent than diclofenac (IC₅₀ = 2.65 mg/L) and aspirin (IC₅₀ = 11.00 mg/L). Antimicrobial tests revealed broad-spectrum activity, with MIC values ranging from 14.7 mg/L (E. coli) to 26.5 mg/L (L. monocytogenes). The EO showed bactericidal effects at higher concentrations (MBC: 25.7–51.0 mg/L), though conventional antibiotics (e.g., gentamicin, vancomycin) were more potent. Chemical analysis identified linalool (42.90%) as the major compound, followed by γ-terpinene (12.30%) and trans-ocimene (11.40%), suggesting terpenes contribute to bioactivity. Conclusion: Piper aduncum EO demonstrates significant antioxidant and antimicrobial potential, supporting its use in natural health products, food preservation, and antimicrobial applications. However, further studies, including in vivo essays and stability tests—are needed to validate its efficacy and safety. The findings highlight its value as a sustainable source of bioactive compounds amid rising antibiotic resistance.