Volatile Constituents and Biological Properties of Essential Oils from Aerial Parts of Gentiana gelida BIEB.

This work reports the chemical composition, antimicrobial and antioxidant activities of essential oils from the aerial parts of Gentiana gelida BIEB. for the first time in literature. The oils from the aerial parts (flower, leaf and stem) were obtained by Clevenger-type apparatus and characterized by GC-FID and GC-MS. While tricosane (21.67%) was the main component of flower oil, hexadecanoic acid was the most abundant component of leaf and stem oils in ratios 26.46% and 31.89%, respectively. Additionally, all essential oils of G. gelida were investigated for their antimicrobial activity against eight Gram negative bacteria, four Gram positive bacteria and five fungi, using agar dilution method and antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl radical scavenging and Folin-Ciocalteu assays. The flower oil of G. gelida showed stronger antimicrobial and antioxidant activities than those of stem and leaf. The amount of total phenolic content and scavenging activity of the flower oil were found 525.35±8.24 mg GAE/L and 49.30±1.25%, respectively.

Assessment of big floods in the Eastern Black Sea Basin of Turkey.

In this study, general knowledge and some details of the floods in Eastern Black Sea Basin of Turkey are presented. Brief hydro-meteorological analysis of selected nine floods and detailed analysis of the greatest flood are given. In the studied area, 51 big floods have taken place between 1955-2005 years, causing 258 deaths and nearly US $500,000,000 of damage. Most of the floods have occurred in June, July and August. It is concluded that especially for the rainstorms that have caused significantly damages, the return periods of the rainfall heights and resultant flood discharges have gone up to 250 and 500 years, respectively. A general agreement is observed between the return periods of rains and resultant floods. It is concluded that there has been no significant climate change to cause increases in flood harms. The most important human factors to increase the damage are determined as wrong and illegal land use, deforestation and wrong urbanization and settlement, psychological and technical factors. Some structural and non-structural measures to mitigate flood damages are also included in the paper. Structural measures include dykes and flood levees. Main non-structural measures include flood warning system, modification of land use, watershed management and improvement, flood insurance, organization of flood management studies, coordination between related institutions and education of the people and informing of the stakeholders.

Composition and antimicrobial activity of the essential oils from flowers of Senecio othonnae, s. racemosus, and s. nemorensis.

The chemical composition of the essential oils of Senecio othonnae, S. racemosus, and S. nemorensis obtained by hydrodistillation of fresh flowers were analysed by GC-FID and GC-MS. A total of seventy-six compounds were identified, constituting over 83.1%, 97.7% and 86.8% of the total oil composition of the flowers of S. othonnae, S. racemosus, and S. nemorensis. The main components of the oils were caryophyllene oxide (18.6%), (E)-beta-farnesene (21.6%), and gamma-curcumene (42.8%), respectively. Sesquiterpene hydrocarbons were the main group of constituents of all three species, forming 34.6%, 73.2%, and 81.8% of the oils, respectively. The oils of S. othonnae, and S. nemorensis showed antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, and Candida tropicalis, but that of S. racemosus was only active against Candida tropicalis.

Synthesis and non-aqueous medium titrations of some new 4-benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives.

The synthesis of 3-alkyl(aryl)-4-(3-ethoxy-4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described. The acetylation and methylation reactions of the compounds 3 giving compounds of type 4 and 5, respectively, were investigated. The newly synthesized compounds were characterized using elemental analyses and IR, (1)H-NMR, (13)C-NMR and UV spectral data. In addition, to investigate the effects of solvents and molecular structure upon acidity,compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide). The half-neutralization potential values and the corresponding pKa values were determined for all cases.