Jordan Nechev

Chemical composition of the sponge Chondrosia reniformis from the Canary Islands

The fatty acid composition of the lipids from Chondrosia reniformis (Nardo, 1847) was investigated and 57 acids were identified. One of them is new for nature and its structure was elucidated by GC/mass-spectrometry. This acid was identified as 8,10-dimethyl-16:0. The sterol composition was relatively simple and only 12 sterols were present. In the volatile fraction, 21 compounds were identified, mainly fatty acids, their esters and hydrocarbons, while in the n-butanol fraction we found mainly free fatty acids and free amino acids, together with significant amounts of sterols which probably are included in some polar complexes.

Lipid composition of the sponge Verongia aerophoba from the Canary Islands

The fatty acid composition of the lipids from the sponge Verongia aerophoba was investigated and 60 acids were identified. Two of them were new and their structures were elucidated by gas chromatography-mass spectrometry. These acids were identified as 20-methylhexacosanoic and Δ5, 9, 22-nonacosatrienoic. Only 13 sterols were present, and aplysterol predominated. In the volatile fraction 13 compounds were identified, mainly fatty acids, their esters and hydrocarbons, while in the n-butanol fraction we found mainly free fatty acids and free amino acids.

Lipids and sterols in Musca domestica L. (Diptera, Muscidae): changes after treatment with sucrose and lead

Total lipid, fatty acid and sterol composition of larvae and adults of Musca domestica was investigated before and after feeding on sucrose syrup or on the same syrup containing 1% lead nitrate. The effects of sucrose and of lead ions were found to be different. In larvae sucrose diet inhibited the fatty acid elongation and stimulated the first stages of their unsaturation. A significant increase of phytosterol concentrations was obtained. These changes increased the cell membrane permeability. The addition of lead caused a decrease of the fatty acid unsaturation, which decreased the cell membrane permeability. In adults the sucrose diet had no effect on the lipid and sterol composition, while the addition of lead decreased the cholesterol concentration. The composition of lipids and sterols also depends on the diet of larvae before pupation. The data obtained suggested that changes in lipid and sterol composition, which control the permeability of the cell membrane, might be an adaptive response of the organism to the changes of the environment.

Lipophylic compounds from Euphorbia peplis L.--a halophytic plant from the Bulgarian Black Sea coast.

Abstract The chemical composition of the lipophylic fraction from the halophytic plant Euphorbia peplis L. was investigated. Compared to other terrestrial higher plants an increase of triacylglycerols and especially of glycolipids was observed. The main phospholipid was phosphatidyl choline, followed by almost equal concentrations of phosphatidyl ethanolamine and phosphatidyl glycerol. A relatively high concentration of phosphatidic acids (6.5% of the total phospholipids) was found. The main sterol appeared to be sitosterol and significant amounts of tetracyclic triterpene alcohols were found. The composition of the volatile compounds is relatively simple and only one chlorinated compound, identified as 2,2-diethoxy-1-chloroethane, was found. There was a strong toxicity of the total lipophylic extract towards Artemia salina.

Chemical composition of the halophyte plant Stachys maritima Gouan from the Bulgarian Black Sea coast

Four groups of metabolites from the halophyte plant Stachys maritima Gouan, family Lamiaceae, were investigated: lipids, sterols, volatiles and polar compounds. Most of the metabolites have been previously reported to possess biological activity. Two of the main substances in the volatile fraction – phenidone and naphthalene, unusual for plants – were products of environmental contamination. This is a typical example of how marine pollutants could transfer and threaten terrestrial organisms via the trophic chain. The n-butanol extract possessed a relatively high antibacterial activity against S. aureus and Candida albicans, but was not active against Escherichia coli.

Composition of Lipophylic Extracts from Two Tunicates, Styela sp. and Phallusia sp. from the Eastern Mediterranean

Sterols, volatiles and lipids were isolated and identified from lipophylic extracts from two tunicates, Styela sp. and Phallusia sp., occurring in the Eastern Mediterranean. Seventeen sterols were identified. The sterol composition of the two organisms appeared to be similar except for the concentrations of 5α-stanols. Both tunicates were characterized by the presence of sterols with a (22Z)-double bond. In the volatiles significant amounts of chlorinated compounds were found (phenols in Styela sp. and hydrocarbons in Phallusia sp.). The fatty acid composition of triacylglycerols and phospholipids of the two tunicates showed significant differences.

Antiradical and Antioxidant Activities of New Natural-like Hydroxylated Biphenyls of Dehydrozingerone, Zingerone and Ferulic Acid

Selected synthesized natural and natural-like hydroxylated biphenyls (dimers) and their corresponding monomers (dehydrozingerone, zingerone and ferulic acid) were tested experimentally for their capacity both as radical scavengers and chain-breaking antioxidants in individual and binary mixture with α-tocopherol. Quantum-chemical calculations at the UB3LYP/6-13+G(d,p) level were used to get full geometry optimization of the compounds in neutral and radical forms. Good correlation between experimental data of radical scavenging and antioxidant activities and predicted activity was achieved.