Antimicrobial and Antibiofilm Activities of the Essential Oil from the Inflorescence of Etlingera elatior (Zingiberaceae) and Its Main Constituents (Dodecanal and 1-Dodecanol)

The spread of antibiotic-resistant pathogens had motivated the search for plant-derived antimicrobial agents, such as essential oils. This work investigated the antibacterial, antifungal and antibiofilm properties of the essential oil from the inflorescence of Etlingera elatior and its major compounds. Dodecanal (42.46%) and 1-dodecanol (25.84%) were the major compounds. The oil, dodecanal and 1-dodecanol were active against Staphylococcus aureus, with minimum bactericidal concentrations of 124, 31 and 62 µg mL-1, respectively. For Pseudomonas aeruginosa, the essential oil had an inhibitory effect against a multidrug resistant isolate (minimum inhibitory concentration (MIC): 4,000 µg mL-1). Dodecanal had an MIC of 60,000 µg mL-1 for all Candida species, but fungicidal activity was only detected for Candida albicans (minimum fungicidal concentration: 60,000 µg mL-1). 1-Dodecanol (60,000 µg mL-1) exhibited fungistatic activity for C. albicans. Biofilm inhibition linked to an anti-adhesive effect of the oil and dodecanal was only detected for the standard S. aureus isolate and C. albicans, respectively. In conclusion, the essential oil from the inflorescence of E. elatior and its major components were more active against nonresistant strains S. aureus. Essential oil, dodecanol and dodecanal showed excellent activity against S. aureus, however, these same materials showed low activity against P. aeruginosa.