Thymol and carvacrol production from leaves of wild Palestinian Majorana syriaca.

Majorana syriaca (Zaatar in Arabic), belonging to the mint family, Labiates, is cultivated widely and grows wild in the mountains of Palestine between the months April to August. In order to determine the secondary metabolites from wild leaves of Palestinian M. syriaca, comparative analysis by static headspace (HS) and steam distillation (SD) GC-MS was used. Among the samples examined, the major constituents identified varied greatly throughout the different harvesting periods. Headspace revealed major volatiles and semi-volatiles of alpha-pinene, beta-myrecene, o-cymene, p-cymene, gamma-terpinene, thymol, and carvacrol. We found that the most abundant monoterpenes, i.e. gamma-terpinene and p-cymene were decreased in the month of May since they are the biogenetic precursors (via enzymic hydroxylation) of the phenolic terpenes, thymol and carvacrol. The harvesting time, location and the thyme type (i.e., wild) affects the yield of essential oils as reflected by normal steam distillation.

Metabolites produced by cyanobacteria belonging to several species of the family Nostocaceae.

This paper provides a comprehensive overview of metabolites, including lipids and lipid-like compounds, nitrogen metabolites, oligopeptides and amino acid derivatives, produced by cyanobacteria of the genera Anabaenopsis, Aphanizomenon, Aulosira, Cylindrospermopsis, Cylindrospermum, Nodularia, and Richelia of the family Nostocaceae.

Metabolites produced by nitrogen-fixing Nostoc species.

This paper provides a comprehensive overview of metabolites, including lipids and lipid-like compounds, boron-containing macrocycles, arsenolipids, oligopeptides and amino acid derivatives, produced by cyanobacteria of the genus Nostoc.

Natural microbial UV radiation filters--mycosporine-like amino acids.

Ozone depletion by anthropogenic gases has increased the atmospheric transmission of solar ultraviolet-B radiation (UV-B, 280-315 nm). There is a logical link between the natural defenses of terrestrial and marine organisms against UV radiation and the prevention of UV-induced damage to human skin. UV light degrades organic molecules such as proteins and nucleic acids, giving rise to structural changes that directly affect their biological function. These compounds offer the potential for development of novel UV blockers for human use. The biological role of mycosporine-like amino acids (MAAs) and scytonemin as a defense against solar radiation in organisms, together with their structure, synthesis, distribution, regulation and effectiveness, are reviewed in this article. This review points to the role of MAAs as a natural defense against UV radiation.

Photoprotection by Cichorum endivia extracts: prevention of UVB-induced erythema, pyrimidine dimer formation and IL-6 expression.

In the gradual process of evolution, plants have developed natural sun protecting substances that enable continuous survival under direct and intense ultraviolet (UV) radiation. As part of our studies of plant-derived pigments that might constitute an alternative to conventional sunscreens, we have tested the ethanolic extracts of roots, stalks, and inflorescences of populations of wild Cichorum endivia subsp. Divaricatum (Asteraceae) in terms of protection against sunburn, and in prevention of UVB-induced pyrimidine dimer formation and IL-6 mRNA expression in the human keratinocyte cell line, HaCaT. Using ELISA technique for detection of pyrimidine dimers and RT-PCR for detection of IL-6, we found that the ethanolic extract of C. endivia roots absorbs radiation in the UVB spectrum and partially prevents induction of pyrimidine dimers and IL-6 expression. Application of the root extract on the skin prior to UVB irradiation totally prevented erythema. Our findings suggest that C. endivia extracts might possess sun-protective qualities that make them useful as sunscreens.

Sterol compositions of the filamentous nitrogen-fixing terrestrial cyanobacterium Scytonema sp.

Thirteen unsaturated sterols were identified by gas chromatography--mass spectrometry using serially-coupled capillary columns from the filamentous nitrogen-fixing terrestrial cyanobacterium Scytonema sp. isolated from the microbial community of cyanobacterial on 'Black Cover' biofilms limestone walls in Jerusalem. The dominant sterols were cholest-5-en-3 beta-ol (18.9%), 3 beta-methoxycholest-5-ene (16.2%) and 3 beta-acetoxycholest-5-ene (11.2%).

Characterization of surface n-alkanes and fatty acids of the epiphytic lichen Xanthoria parietina, its photobiont a green alga Trebouxia sp., and its mycobiont, from the Jerusalem hills.

Surface alkanes and fatty acids from the thalli of the lichen Xanthoria parietina, its photobiont Trebouxia sp., and its mycobiont were analysed by GC-MS. The green alga Trebouxia sp. synthesized mainly unsaturated fatty acids such as (Z,Z,Z)-9,12,15-18 : 3 (Z,Z)-9,12-18 : 2 and (Z)-9-18 : 1, and light alkanes C8-C15 (up to 83% of total n-alkanes). However, the mycobiont contained mainly saturated fatty acids such as hexadecanoic (16 : 0) and octadecanoic acid (18 : 0), and also very long-chain n-alkanes C22-C34. Dehydroabietic acid was found in both lichen and mycobiont. The occurrence of different amounts of n-alkanes and fatty acids in the photobionts and mycobionts of X. parietina was shown for the first time. Lichens collected from different locations in the Jerusalem hills contained n-alkanes ranging in concentration from 187 to 211 mg x (g dry wt)-1; n-alkane concentrations in the photobiont and mycobiont were 17-24 and 215-262 mg x (g dry wt)-1, respectively.

Fatty acid composition of six freshwater wild cyanobacterial species.

Hydroxy, n-saturated, branched, dioic, and unsaturated fatty acids in six freshwater wild cyanobacteria (Chroococcus minutus, Lyngbya ceylanica, Merismopedia glauca, Nodularia sphaerocarpa, Nostoc linckia, and Synechococcus aeruginosus) collected from different lakes and springs of Israel have been identified by gas chromatography-mass spectrometry (GC-MS).

Polar lipids and fatty acids of three wild cyanobacterial strains of the genus Chroococcidiopsis.

The occurrence of n-saturated, branched, and unsaturated fatty acids of 3 wild terrestrial strains of the genus Chroococcidiopsis (Order Chroococcales): C. supralittoralis, C. umbratilis, and C. versatilis collected from Lake Kinneret, Dead Sea, and Ein Kerem (Jerusalem) was investigated and individual compounds identified by gas chromatography-mass spectrometry. Polar lipids also were examined. Among polar lipids (studied using two-dimensional thin-layer chromatography) were as major glycolipids isolated: monogalactosyl-diacylglycerols, digalactosyl-diacylglycerols, 6-sulfoquinovosyl-diacylglycerols and phosphatidylglycerol. Nonphosphorus betaine-containing lipid, viz. N,N,N-trimethylhomoserin-4-O-yl-diacylglycerol, was found for the first time in cyanobacterial species.

Variability of hydrocarbon and fatty acid components in cultures of the filamentous cyanobacterium Scytonema sp. isolated from microbial community "black cover" of limestone walls in Jerusalem.

The hydrocarbon and lipid components of four strains of the filamentous cyanobacterium Scytonema sp. isolated from microbial community "Black Cover" of limestone walls in Jerusalem were identified by gas chromatography-mass spectrometry using serially coupled capillary columns. The dominant compounds were: 1-heptadecyne (1.5-8%), hexadecanoic acid (14-36%), (Z,Z)-9,12-octadecadienoic acid (12-30%), (Z,Z,Z)-9,12,15-octadecatrienoic acid (6-12%), n-heptadecane (4-16%), and 1-heptadecene (1.5-8%). In addition to unsaturated alkanes and fatty acids, the very long-chain (C30-C32) hydrocarbons, squalene (2.4-3.0%), and branched 4,8,12-trimethyl-C13:0 acid were also isolated. Two major hydrocarbons were detected in the cyanobacteria species using GC-MS and 13C-NMR.

Use of serially coupled capillary columns with different polarity of stationary phases for the separation of the natural complex volatile mixture of the marine red alga Corallina elongata.

Separation of a complex of natural volatile compounds using serially coupled capillary columns with different polarity of stationary phases by gas chromatography-mass spectrometry from the medicinal marine red alga Corallina elongata is reported. Nearly 200 hydrocarbons, halogen compounds, fatty acids, and other metabolites were found. Using this gas chromatography procedure we demonstrate the successful separation of different volatile organic compounds.

[Bromo- and iodo-containing alkaloids from marine microorganisms and sponges]. / Brom- i iodsoderzhashchie alkaloidy morskikh mikroorganizmov i gubok.

The taxonomic distribution, structure, and biological activity of halogenated alkaloids isolated from marine microorganisms and sponges are reviewed. The structures of nearly 140 natural bromo- and iodo-containing alkaloids are shown.

Hydrocarbons, fatty acids, and lipids of freshwater grasses of the Potamogetonaceae family.

The composition of hydrocarbons, fatty acids, and of total, polar, and neutral lipids was studied in freshwater Potamogetonaceae grasses collected in two different regions of the Volga river. More than 40 fatty acids and hydrocarbons were separated and identified by chromato-mass spectrometry. The variability of lipid characteristics of plants of the same family is discussed.

Polyhalogenated homosesquiterpenic fatty acids from Plocamium cartilagineum.

We describe the composition of novel polyhalogenated homosesquiterpenic acids from the red alga Plocamium collected during summer on Maltese Islands and Corsica. The compounds, predominantly derivatives with unique groups (bromine, chlorine, and diene), were identified by means of 1H and 13C NMR, MS, IR and UV spectra.

Bromoallenic lipid compounds from lichens of central Asia.

The composition of two bromoallenic aliphatic fatty acids obtained from lichens collected around Lake Issyk-Kul (central Asia) is described. These compounds were identified by means of 1H and 13C NMR, MS and IR spectra.

Dicarboxylic and fatty acid compositions of cyanobacteria of the genus Aphanizomenon.

The occurrence of dioic, hydroxy, branched, and unsaturated fatty acids in cyanobacteria of the genus Aphanizomenon growing in different freshwater lakes has been studied. Unusual dicarboxylic (from 4.52 to 7.14%) and other fatty acids were identified by gas chromatography/mass spectrometry (GC/MS).

Fatty acid amides from freshwater green alga Rhizoclonium hieroglyphicum.

Freshwater green algae Rhizoclonium hieroglyphicum growing in the Ural Mountains were examined for their fatty acid amides using capillary gas chromatography-mass spectrometry (GC-MS). Eight fatty acid amides were identified by GC-MS. (Z)-9-octadecenamide was found to be the major component (2.26%).

Occurrence of diacylglyceryltrimethylhomoserines and major phospholipids in some plants.

Over 40 higher plant species were examined for the contents of total lipids, phospholipids, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG) by using micro-HPTLC. The results showed a wider range of plants containing betaine lipids. So, DGTS was found in some higher plant species, not studied earlier, belonging to Equisetophyta, Polypodiophyta; the lipid composition of many other species from Spermatophyta was also studied. It was demonstrated that more primitive plant species contained, as a rule, the betaine lipid DGTS. The quantitative data for the distribution of the main phospholipid classes PC, PE, and PG in various plant species and their tissues are given in this paper.

Variability of lipid constituents of the coil cyanobacterium Microcoleus vaginatus from the Dead Sea basin and Negev desert.

A study of lipids of the soil cyanobacterium Microcoleus vaginatus, which was isolated from microbial crusts collected in the Dead Sea basin and in the Negev desert, was performed. Twenty-six hydrocarbons and fatty acids were separated and identified by GC/MS using serially coupled capillary columns of different polarity. Changes in the lipid composition were evaluated by comparison of samples collected from different locations. Heptadecane, 1-heptadecene, 6- and 7-methylheptadecane, hexadecanoic and 9(Z)-octadecenoic acids were identified as the major constituents. Biochemical mechanisms of production of the different lipid compounds under UV irradiation are proposed.

Comparative study of the lipids of four dominating species of freshwater plants and algae of the Shulgan river.

The fatty acid and lipid compositions of four dominating species of plants and algae of the Shulgan river--Alliaria petiolata, Rhynchostegium riparioides, Sphaeroplea annulina, and Rhizoclonium hieroglyphicum--were studied. The composition of phospho-, glyco-, and neutral lipids was investigated. A betaine lipid 1(3), 2-diacylglyceryl-(3)-O-4-(N,N,N-trimethyl)homoserine was detected in the polar lipid fraction of the Rhynchostegium riparioides bryophyte. Characteristic distribution of lipids and fatty acids of freshwater plants and algae is discussed in term of various species specificity.