Chemotaxonomic significance of the essential oils of 18 Ferula species (Apiaceae) from Iran

To evaluate the chemotaxonomic significance of the essential oils of 23 populations of 18 Iranian Ferula species, the chemical composition of the oils was investigated by GC/FID and GC/MS. Altogether, 84 constituents, representing 81.3-99.7% of the total composition of the oils, have been identified. The composition of six species of the genus, i.e., F. oopoda, F. foetida, F. behboudiana, F. diversivittata, F. galbaniflua, and F. hezarlalehzarica, has been reported for the first time. The main constituents identified were α-terpinyl acetate (73.3%), 2,3,4-trimethylthiophene (2; 49.0%), sabinene (75.3%), verbenone (5; 69.4%), β-pinene (59.0-66.3%), and (Z)-β-ocimene (41.7%). Cluster analysis (CA) of the percentage content of the essential oil components of the Ferula species resulted in the characterization of four groups, i.e., taxa containing either i) monoterpene hydrocarbons, ii) oxygenated monoterpenes, iii) organosulfur compounds, or iv) monoterpene, sesquiterpene, and aliphatic hydrocarbons as the principal classes of compounds. Based on the results obtained, the chemical independence of F. hirtella from F. szowitsiana and of F. galbaniflua from F. gummosa at the specific level was concluded and their positions as distinct species were confirmed. The chemotaxonomic relationships among the representatives of the genus Ferula have been discussed in detail.     

Antibacterial and antioxidant activity and essential oil composition of Grammosciadium scabridum Boiss. from Iran

The in vitro antibacterial and antioxidant activity of the essential oil and its two main components of Grammosciadium scabridum Boiss. (Apiaceae) growing wild in Iran, as well as the composition of its essential oil were studied. A total of 19 compounds representing 99.9% of the oil has been identified. Gamma-Terpinene (73.5%), p-cymene (14.2%) and (E)-beta-farnesene (5.3%) were characterized as the main components. The oil showed remarkable activity against three Gram-negative and four Gram-positive test bacteria, with minimal inhibitory concentration (MIC) values ranging from 0.31 to 10.00 mg/ml. The oil and its two main components were also subjected to screening for their possible antioxidant activity by using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) assay. The free radical scavenging capacity of the oil was determined with an IC50 value of 6.6 mg/ml.     

Antibacterial activity and chemical composition of the essential oil of Grammosciadium platycarpum Boiss. from Iran

The chemical composition of the essential oils obtained from two samples (GP1 and GP2) of Grammosciadium platycarpum Boiss. was analyzed by GC and GC-MS. The analysis of the oils resulted in the identification of twenty-two constituents. Linalool (79.0%-GP1, 81.8%-GP2) and limonene (10.0%, 5.8%) were found to be the major components, respectively. The in vitro antibacterial activities of these oils and their main compounds against seven Gram-positive and Gram-negative bacteria were investigated. The results exhibited that the total oils and their major components possess strong to moderate activities against all the tested bacteria except for Pseudomonas aeruginosa.     

Standardizing GC-MS metabolomics

Metabolomics being the most recently introduced "omic" analytical platform is currently at its development phase. For the metabolomics to be broadly deployed to biological and clinical research and practice, issues regarding data validation and reproducibility need to be resolved. Gas chromatography-mass spectrometry (GC-MS) will remain integral part of the metabolomics laboratory. In this paper, the sources of biases in GC-MS metabolomics are discussed and experimental evidence for their occurrence and impact on the final results is provided. When available, methods to correct or account for these biases are presented towards the standardization of a systematic methodology for quantitative GC-MS metabolomics.     

Countercurrent tangential chromatography for large-scale protein purification

Recent advances in cell culture technology have created significant pressure on the downstream purification process, leading to a "downstream bottleneck" in the production of recombinant therapeutic proteins for the treatment of cancer, genetic disorders, and cardiovascular disease. Countercurrent tangential chromatography overcomes many of the limitations of conventional column chromatography by having the resin (in the form of a slurry) flow through a series of static mixers and hollow fiber membrane modules. The buffers used in the binding, washing, and elution steps flow countercurrent to the resin, enabling high-resolution separations while reducing the amount of buffer needed for protein purification. The results obtained in this study provide the first experimental demonstration of the feasibility of using countercurrent tangential chromatography for the separation of a model protein mixture containing bovine serum albumin and myoglobin using a commercially available anion exchange resin. Batch uptake/desorption experiments were used in combination with critical flux data for the hollow fiber filters to design the countercurrent tangential chromatography system. A two-stage batch separation yielded the purified target protein at >99% purity with 94% recovery. The results clearly demonstrate the potential of using countercurrent tangential chromatography for the large-scale purification of therapeutic proteins.