Stefka Dimitrova-Konaklieva

Effect of salinity on lipid composition of Cladophora vagabunda

The main lipid classes and their fatty acid composition were investigated in Cladophora vagabunda inhabiting waters with different salinities or subjected to salt-stress. Most of the observed changes probably have adaptive value. Differences between adaptation and stress, and also the effects of the degree of the stress are discussed.

Antibacterial, antiviral, and cytotoxic activities of some red and brown seaweeds from the Black Sea.

Abstract Chloroform extracts, n- butanol extracts, water extracts,and volatile compounds from seven species belongingtosix Black Sea genera of brown algae and 10 speciesbelonging to seven Black Sea genera of red algae wereassessed for antibacterial, antiviral, and cytotoxic prop-erties. Most of the extracts showed pronounced effectsagainst the Gram (q) bacterium Staphylococcus aureus .Activity towards the Gram (-) bacterium Escherichia coli was found in only few cases. A significant reduction inreplication of influenza and Herpes simplex viruses in cellcultures was observed. Cytotoxic effect was establishedin a significant proportion of the algae investigated. Thebiological activities may be attributed to the presence ofvolatile compounds, some phenols, free fatty acids andtheir oxidized derivatives, eucalyptol, the methyl ester ofphenyl acetic acid, and 1,2-dihydroxy ethane sulfonate. Keywords: biological activities; extracts; red and brownBlack Sea algae. Introduction Marine algae have been evaluated as an attractivesourceof potential drug compounds in several biochemical andpharmacological investigations (Kerr and Kerr 1999,Luescher-Mattli 2003, Simmons et al. 2005, Lahaye andRobic 2007). Being in permanent contact with pollutants(and in order to survive in such unfriendly environments),different marine organisms, such as fungi, viruses, bac-teria, etc., synthesize or accumulate defensive com-pounds. Diverse algal extracts have been investigatedfortheir antimicrobial, cytotoxic, antitumor, antiviral, andanti-inflammatory properties (Konig and Wright 1996,Mandal et al. 2007). Our preliminary investigationsshowed that some widespread Black Sea algae possessantimicrobial, antiviral, antifungal and cytotoxic activities(Stefanov et al. 1998, Kujumdjiev et al. 1999, Serkedjieva2000, Kamenarska et al. 2002). Evidently, most of thebiologically active compounds found in marine algaehave defensive functions. A proportion of these com-pounds are secreted into surrounding seawater.In the present study, we continued the investigation ofantibacterial, cytotoxic, and antiviral activities of themostwidely distributed macroalgae in the Bulgarian part of theBlack Sea, which has not been studied until now. More-over, the results obtained were compared with the chem-ical compositions of the corresponding extracts.

Sterols and volatiles in Cystoseira barbata and Cystoseira crinita from the black sea

Abstract Five sterols were identified in Cystoseira barbata and seven sterols in C. crinita . Saringasterol appeared to be an artefact. Volatiles in C. barbata consisted mainly of halogenated hydrocarbons, while in C. crinita terpenoids predominate. The results obtained can be used in chemosystematics.

The fatty acid composition of a Vibrio alginolyticus associated with the alga Cladophora coelothrix. Identification of the novel 9-methyl-10-hexadecenoic acid

The fatty acid composition of a new strain of Vibrio alginolyticus, found in the alga Cladophora coelothrix, was studied. Among 38 different fatty acids, a new fatty acid, 9-methyl-10-hexadecenoic acid and the unusual 11-methyl-12-octadecenoic acid, were identified. Linear alkylbenzene fatty acids, such as 10-phenyldecanoic acid, 12-phenyldodecanoic acid and 14-phenyltetradecanoic acid, were also found in V. alginolyticus. The alga contained 43% saturated fatty acids, and 28% C16–C20 polyunsaturated fatty acids of the n−3 and n−6 families.

Volatile compounds from some Black Sea red algae and their chemotaxonomic application

Abstract Volatile compounds from the Black Sea red algae Bangia fuscopurpurea, Gelidium latifolium, Callithamnion granulatum, Ceramium elegans, Laurencia papillosa and Laurencia coronopus were obtained by distillation-extraction and analysed by GC/MS. Different groups of compounds were identified: hydrocarbons, alkylated benzenes, alcohols, phenols, aldehydes, ketones, acids, esters, terpenes, nitrogen- and halogen-containing compounds. The results are compared with some recent data for the composition of the volatile compounds from four previously investigated Black Sea red algae, which are at different evolutionary stages. On the basis of their qualitative and semi-quantitative composition some chemotaxonomic conclusions are proposed. The eventual functions of some of the volatile compounds are briefly discussed.

Effect Of Diesel Fuel Pollution On The Lipid Composition Of Some Wide-Spread Black Sea Algae And Invertebrates

Two green algae (Ulva rigida and Cladophora coelothrix), the mussel Mytilus galloprovincialis and the snail Rapana thomasiana from the Bulgarian Black Sea shore have been treated with diesel fuel (100 mg l-1) in an aquarium with sea-water for three days. The lipids and their fatty acid changes have been examined. Significant changes have been observed mainly in the polar lipids and in the saturation of the fatty acids. These changes appeared to be bigger in the evolutionary less advanced species from both groups of marine organisms D algae and invertebrates (Ulva rigida and Mytilus galloprovincialis respectively). The data obtained could be used for a biomonitoring of the pollution

Terpenoids and sterols in Cladophora vagabunda

Abstract Ten sterols and ursolic acid were identified in C. vagabunda. Hexahydrofarnesylacetone, dihydroactinidiolide, benzyl alcohol, myrtenol and 2-nonanone were found in the volatile oil of this alga. The eventual participation of C. vagabunda in Black Sea food chains has been discussed.

Chemical composition and biological activity of the brackish-water green alga Cladophora rivularis (L.) Hoek

Abstract The chemical composition of the brackish-water green alga Cladophora rivularis was investigated. Seven sterols were identified and the stereochemistry of the most common forms was established. Thirty-eight and 21 compounds were identified in the volatile and polar fractions, respectively. The main lipid classes were isolated and their fatty acid compositions established. The antibacterial, antimycotic and cytotoxic activities of the extracts were investigated. Comparisons were made with previously investigated marine and freshwater Cladophora species. Results obtained give information on the effect of salinity on algal metabolism.

Comparative Study of the Volatile Compounds from Some Black Sea Brown Algae

Abstract Volatile compounds from seven species of brown algae, wide-spread in the Black Sea, were obtained by distillation-extraction and investigated by GC/MS. Different groups of compounds were identified: hydrocarbons, alkylated benzenes, alcohols, phenols, aldehydes, ketones, acids, esters, terpenes, sulfur- and chlorine-containing compounds. On the basis of their qualitative and semi-quantitative composition some conclusions about the taxonomy and evolution of the species investigated are proposed. The functions of some of the volatile compounds are discussed.

Sterols from some black sea ulvaceae

Abstract The free and esterified sterol composition of Ulva rigida and Enteromorpha linza (Ulvaceae) from the Black Sea was investigated. The main sterol component of Ulva rigida was identified as fucosterol. The influence of the season and water pollution on the sterol composition was investigated. The origin of the C 26 ,- and C 25 -sterols and of saringasterol in these seaweeds is discussed.