beta-bisabolene and alpha-bergamotene

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

Oral infections such as periodontitis and tooth decay are the most common diseases of humankind. Oleoresins from different copaifera species display antimicrobial and anti-inflammatory activities. Copaifera reticulata is the commonest tree of this genus and grows abundantly in several Brazilian states, such as Pará, Amazonas, and Ceará. The present study has evaluated the chemical composition and antimicrobial potential of the Copaifera reticulata oleoresin (CRO) against the causative agents of tooth decay and periodontitis and has assessed the CRO cytotoxic potential. Cutting edge analytical techniques (GC-MS and LC-MS) aided the chemical characterization of CRO. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), determination of the Minimum Bactericidal Concentration (MBC), determination of the Minimum Inhibitory Concentration of Biofilm (MICB50), Time Kill Assay, and Checkerboard Dilution. Conduction of XTT assays on human lung fibroblasts (GM07492-A cells) helped to examine the CRO cytotoxic potential. Chromatographic analyses revealed that the major constituents of CRO were β-bisabolene, trans-α-bergamotene, β-selinene, α-selinene, and the terpene acids ent-agathic-15-methyl ester, ent-copalic acid, and ent-polyalthic acid. MIC and MBC results ranged from 6.25 to 200 μg/mL against the tested bacteria. The time-kill assay conducted with CRO at concentrations between 50 and 100 μg/mL showed bactericidal activity against Fusobacterium nucleatum (ATCC 25586) and Streptococcus mitis (ATCC 49456) after 4 h, Prevotella nigrescens (ATCC 33563) after 6 h, Porphyromonas gingivalis (ATCC 33277) and Lactobacillus casei (clinical isolate) after 12 h, and Streptococcus salivarius (ATCC 25975) and Streptococcus mutans (ATCC 25175) after 18 h. The fractional inhibitory concentration indexes (FICIs) revealed antagonistic interaction for Lactobacillus casei (clinical isolate), indifferent effect for Porphyromonas gingivalis (ATCC 33277), Fusobacterium nucleatum (ATCC 25586), Prevotella nigrescens (ATCC 33563), and Streptococcus salivarius (ATCC 25975), and additive effect for Streptococcus mutans (ATCC 25175) and Streptococcus mitis (ATCC 49456). Treatment of GM07492-A cells with CRO demonstrated that concentrations up to 39 μg/mL significantly reduced cell viability as compared to the negative control, being IC50 equal to 51.85 ± 5.4 μg/mL. These results indicated that CRO plays an important part in the search for novel sources

Topics: Anti-Bacterial Agents; Bridged Bicyclo Compounds; Cell Line; Cell Survival; Dental Caries; Fabaceae; Fibroblasts; Humans; Lacticaseibacillus casei; Microbial Sensitivity Tests; Monocyclic Sesquiterpenes; Periodontitis; Plant Extracts; Porphyromonas gingivalis; Prevotella nigrescens; Sesquiterpenes; Streptococcus mutans; Streptococcus salivarius; Terpenes

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