caryophyllene and beta-bisabolene

The chemical composition of the essential oil obtained from aerial parts of Nepeta graciliflora was analysed, for the first time, by GC-FID and GC-MS. A total of 27 compounds were identified, constituting over 91.44% of oil composition. The oil was strongly characterised by sesquiterpenes (86.72%), with β-sesquiphellandrene (28.75%), caryophyllene oxide (12.15%), α-bisabolol (8.97%), α-bergamotene (8.51%), β-bisabolene (6.33%) and β-Caryophyllene (5.34%) as the main constituents. The in vitro activity of the essential oil was determined against four micro-organisms in comparison with chloramphenicol by the agar well diffusion and broth dilution method. The oil exhibited good activity against all tested organisms.

Topics: Anti-Bacterial Agents; Bridged Bicyclo Compounds; Gas Chromatography-Mass Spectrometry; Microbial Sensitivity Tests; Monocyclic Sesquiterpenes; Nepeta; Oils, Volatile; Polycyclic Sesquiterpenes; Sesquiterpenes

The chemical composition of essential oil obtained by hydrodistillation of the leaves of Pachira glabra Pasq., (PgEO) has been studied by Gas Chromatography (GC) and Gas Chromatography coupled with Mass Spectrometry (GC/MS). Thirty three constituents representing 98.4% of total contents were identified from the essential oil. The major constituents of oil were limonene (23.2%), β-caryophyllene (14.5%), phtyol (8.5%) and β-bisabolene (6.3%). The antimicrobial activity of the PgEO was evaluated against a panel of ten bacteria and three fungal strain using agar diffusion and broth microdilution methods. Results have shown that the PgEO exhibited moderate to strong antimicrobial activity against the tested microorganisms except Citrobacter youagae, Micrococcus spp. and Proteus spp. The activity zones of inhibition (ZI) and minimum inhibitory concentrations (MIC) ranged between 13.7 mm-24.0 mm and 0.3 mg/mL-2.5 mg/mL, respectively. The insecticidal activity of PgEO was assayed against the adult Sitophilus zeamais. The lethal concentrations (LC50 and LC90) of the PgEO showed it to be toxic against adult S. zeamais at 32.2 and 53.7 mg/mL, respectively. This is the first report on the chemical composition and in vitro biological activities of essential oil of P. glabra growing in Nigeria.

Topics: Animals; Anti-Bacterial Agents; Bacteria; Bombacaceae; Chromatography, Gas; Cyclohexenes; Drug Resistance, Bacterial; Gas Chromatography-Mass Spectrometry; Insecticides; Limonene; Monocyclic Sesquiterpenes; Oils, Volatile; Phytol; Plant Leaves; Polycyclic Sesquiterpenes; Sesquiterpenes; Terpenes

The essential oil of the Greek endemic species Marrubium thessalum Boiss. & Heldr. (Lamiaceae) was obtained by the hydrodistillation of its aerial parts during the flowering stage. The composition of the oil was analysed by GC and GC-MS. Thirty compounds were identified. The oil was devoid of monoterpenes, while sesquiterpenes constituted the major fraction. The main components of the oil were caryophyllene oxide (21.7%), β-caryophyllene (17.6%), germacrene D (15.3%), β-bisabolene (12.6%) and trans-β-farnesene (8.1%).

Topics: Chromatography, Gas; Gas Chromatography-Mass Spectrometry; Greece; Marrubium; Monocyclic Sesquiterpenes; Oils, Volatile; Plant Components, Aerial; Polycyclic Sesquiterpenes; Sesquiterpenes; Sesquiterpenes, Germacrane

Sorghum (Sorghum bicolor) plants damaged by insects emit a blend of volatiles, predominantly sesquiterpenes, that are implicated in attracting natural enemies of the attacking insects. To characterize sesquiterpene biosynthesis in sorghum, seven terpene synthase (TPS) genes, SbTPS1 through SbTPS7, were identified based on their evolutionary relatedness to known sesquiterpene synthase genes from maize and rice. While SbTPS6 and SbTPS7 encode truncated proteins, all other TPS genes were determined to encode functional sesquiterpene synthases. Both SbTPS1 and SbTPS2 produced the major products zingiberene, β-bisabolene and β-sesquiphellandrene, but with opposite ratios of zingiberene to β-sesquiphellandrene. SbTPS3 produced (E)-α-bergamotene and (E)-β-farnesene. SbTPS4 formed (E)-β-caryophyllene as the major product. SbTPS5 produced mostly (E)-α-bergamotene and (Z)-γ-bisabolene. Based on the genome sequences of sorghum, maize and rice and the sesquiterpene synthase genes they contain, collinearity analysis identified the orthologs of sorghum sesquiterpene synthase genes, except for SbTPS4, in maize and rice. Phylogenetic analysis implied that SbTPS1, SbTPS2 and SbTPS3, which exist as tandem repeats, evolved as a consequence of local gene duplication in a lineage-specific manner. Structural modeling and site-directed mutagenesis experiments revealed that three amino acids in the active site play critical roles in defining product specificity of SbTPS1, SbTPS2, SbTPS3 and their orthologs in maize and rice. The naturally occurring functional variations of sesquiterpene synthases within and between species suggest that multiple mechanisms, including lineage-specific gene duplication, subfunctionalization, neofunctionalization and pseudogenization of duplicated genes, have all played a role in the dynamic evolution of insect-induced sesquiterpene biosynthesis in grasses.

Topics: Alkyl and Aryl Transferases; Animals; Biological Evolution; Bridged Bicyclo Compounds; Catalytic Domain; Gene Duplication; Herbivory; Insecta; Monocyclic Sesquiterpenes; Mutagenesis, Site-Directed; Oryza; Phylogeny; Plant Proteins; Polycyclic Sesquiterpenes; Sesquiterpenes; Sorghum; Volatile Organic Compounds; Zea mays

The copaiba tree (Copaifera spp.) produces an oleoresin which is highly valued due to its medicinal properties. The chemical composition of C. reticulata oleoresin was characterized, and its variability related to seasonal variation (dry and rainy seasons), to successive extractions, and to several factors associated with tree morphometry, disease, and surrounding vegetation structure was investigated. Oleoresin was collected from 24 C. reticulata individuals between October 2006 and March 2008. For seven individuals, oleoresin was extracted for a second time between three and nine months after the first extraction. For each tree, several morphometric variables, viz., the presence of termites, vines, and holes as well as the soil type and surrounding vegetation structure, were recorded. The chemical composition and concentration of the main volatile compounds were identified by GC/MS. Almost 100% of the constituents were sesquiterpenes, the three main ones being β-caryophyllene, trans-α-bergamotene, and β-bisabolene. A classification analysis separated the C. reticulata individuals in two main groups and further divided one of the main groups in two subgroups, which were defined by different concentrations of the three main compounds. The results showed high intra-population variability in the composition and concentration of sesquiterpenes, this being comparable to the interspecific variability. It was not possible to determine a clear influence of environmental, morphometrical, and structural factors on the oleoresin composition, although some compounds varied according to the soil type, the volume of oleoresin extracted, and the crown surface.

Topics: Bridged Bicyclo Compounds; Fabaceae; Gas Chromatography-Mass Spectrometry; Monocyclic Sesquiterpenes; Plant Extracts; Polycyclic Sesquiterpenes; Seasons; Sesquiterpenes