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), ß-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. sayapensis against 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.

Immunomodulatory effects of 1-(6-hydroxy-2-isopropenyl-1-benzofuran-5-yl)-1-ethanone from Petasites hybridus and its synthesized benzoxazepine derivatives.

1-(6-Hydroxy-2-isopropenyl-1-benzofuran-5-yl)-1-ethanone (1), isolated from the roots of Petasites hybridus L., and a series of synthetic benzoxazepine derivatives of compound 1 (2-6) were evaluated for their immunomodulatory effects. The compounds were evaluated for their effects on the respiratory burst of human whole blood and isolated human polymorphonuclear leukocytes (PMNs) using luminol- and lucigenin-based chemiluminescence (CL) assays, and their effect on chemotactic migration of PMNs was assessed using the Boyden chamber technique. Compound 1 exhibited stronger inhibition than acetylsalicylic acid (ASA) on luminol-enhanced CL of PMNs. It also inhibited PMN chemotaxis with an IC50 value comparable to that of ibuprofen. Of the compounds tested, 5 was the most effective in inhibiting luminol-enhanced CL and also strongly inhibited lucigenin-enhanced CL with IC50 values lower than that of ASA. Compound 2 was the most active in inhibiting migration of PMNs and was five times stronger than ibuprofen. The results suggest that compound 1 and its synthesized benzoxazepine derivatives, especially compounds 2 and 5, were able to modulate the innate immune response of phagocytes at different steps, emphasizing their potential as leads for the development of new immunomodulatory agents.

Acuminatol and other antioxidative resveratrol oligomers from the stem bark of Shorea acuminata.

A new resveratrol dimer, acuminatol (1), was isolated along with five known compounds from the acetone extract of the stem bark of Shorea acuminata. Their structures and stereochemistry were determined by spectroscopic methods, which included the extensive use of 2D NMR techniques. All isolated compounds were evaluated for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA) and the ß-carotene-linoleic acid (BCLA) assays, and compared with those of the standards of ascorbic acid (AscA) and butylated hydroxytoluene (BHT). All compounds tested exhibited good to moderate antioxidant activity in the DPPH assay (IC50s 0.84 to 10.06 mM) and displayed strong inhibition of ß-carotene oxidation (IC50s 0.10 to 0.22 mM). The isolated compounds were evaluated on the Vero cell line and were found to be non-cytotoxic with LC50 values between 161 to 830 µM.