Chemical composition, antioxidant, and antibacterial activity of essential oils from Etlingera sayapensis A.D.Poulsen & Ibrahim

Objective: To report the chemical composition and bioactivity(including antioxidant and antimicrobial activity) of essential oils from the rhizomes, stems, and leaves of Etlingera sayapensis(E. sayapensis) A.D. Poulsen & Ibrahim for the first time. Methods: First, the essential oils were obtained using a Clevenger-type apparatus. Then, the essential oils compositions were identified by chromatography methods including GC-FID and GC-MS. For the next step, DPPH radical scavenging activity(RSA), β-carotene bleaching(BCB), and ferrous ion chelating ability(FIC) were chosen to evaluate the essential oils antioxidant activity. Finally, disc diffusion assay and minimum inhibitory concentration method(MIC) was applied to investigate antimicrobial activity of the rhizomes and leaves oils of E. sayapensisagainst 18 microorganisms. Results: All of the oils contained oxygenated monoterpenes(leaves: 74.18%, stems: 75.60%, and rhizome: 54.61%), The essential oil obtained from leaves contained high amount of carvone(21.38%), cis-carveol(13.49%); The rhizomes oil was rich in linalool formate(25.47%), eugenol(11.84%); and the stems oil was dominated by α-terpineol(39.86%), linalool formate(30.55%). The leaves oil represented the highest ability in all of the antioxidant activity tests. For antimicrobial activity, the rhizome oil presented more active when compared to leaves oil against Bacillus subtilis, Bacillus thuringiensis, Staphylococcus aureus, methicillin resistant Staphylococcus aureus(MRSA), Aeromonas hydrophila, Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Shigella sonnei, Serratia marcescens, Vibrio parahaemolyticus, Candida albicans, and Candida parapsilosis. Conclusions:The most components of the essential oils belong to oxygenated monoterpenes. Linalool formate, carvone, and α-terpineol are found as the most abundant compounds in the oils of the different parts of E. sayapensis. The rhizomes oil can prevent the growth of wide spectrum microorganisms; however, the oils are not highly potent in antioxidant assays.