Phospholipid studies of marine organisms: V1 new α-methoxy acids fromHigginsia tethyoides

Berchemiosides A-C, 2-Acetoxy-ω-phenylpentaene Fatty Acid Triglycosides from the Unripe Fruits of Berchemia berchemiifolia

Three compounds in a new class of 2-acetoxy-ω-phenylpentaene fatty acid triglycosides, berchemiosides A-C (1-3), and a biosynthetically related phenolic glycoside (4) were isolated from the unripe fruits of Berchemia berchemiifolia, along with three flavonoid 5-O-diglycosides (5-7) and three known flavonoids (8-10). Their chemical structures including absolute configurations were determined by spectroscopic analysis in combination with chemical derivatization. The pentaene group of 1 was found to have (6E,8E,10Z,12Z,14E)-geometry, whereas those of 2 and 3 exhibited all-E geometries. The isolated compounds were examined for their cytotoxicity and xanthine oxidase (XO) inhibitory activity; only compound 7 showed weak XO inhibitory activity.

Novel Very Long-Chain α-Methoxylated Δ5,9 Fatty Acids from the Sponge Asteropus niger Are Effective Inhibitors of Topoisomerases IB

The novel fatty acids (2R,5Z,9Z)-2-methoxy-25-methyl-5,9-hexacosadienoic acid (1a) and (2R,5Z,9Z)-2-methoxy-24-methyl-5,9-hexacosadienoic acid (1b) were isolated in 80 % purity from the Caribbean sponge Asteropus niger by chloroform/methanol extraction followed by solvent partitioning and silica gel column chromatography. The compounds were characterized by utilizing a combination of gas chromatography-mass spectrometry, nuclear magnetic resonance, and circular dichroism. Acids 1a and 1b were not detected in the phospholipids (PtdCho and PtdIns) of the sponge, but rather as free FA and possibly in glycosylceramides. The mixtures of 1a and 1b displayed cytotoxicity towards THP-1 and HepG2 cells with EC50's between 41 and 35 μg/mL. Apoptosis was not the preferred mode of cell death induced by 1a-1b in the THP-1 cells. This implies other types of cytotoxicity mechanisms, such as membrane disruption and/or the inhibition (EC50 = 1.8 μg/mL) of the human topoisomerase IB enzyme (hTopIB), with a mechanism of inhibition different from the one displayed by camptothecin (CPT). In a separate experiment, the mixture of 1a and 1b also displayed cytotoxicity towards ex vivo mouse splenocytes infected with Leishmania infantum amastigotes (IC(50) = 0.17 mg/mL) and free living promastigotes (IC(50) = 0.34 mg/mL). It was also found that the FA were inhibitory of the Leishmania topoisomerase IB (LTopIB) with an EC(50) = 5.1 μg/mL. Taken together, 1a and 1b represent a new class of FA with potential as TopIB inhibitors that preferentially inhibit hTopIB over LTopIB.

Comparison of the antibacterial activity, volatiles and fatty acid composition of lipids of Phycopsis species collected at different locations from the Bay of Bengal (Orissa coast)

The fatty acid composition as well as the volatiles and an antibacterial screening of the total lipids isolated from marine sponge Phycopsis sp. collected at two different locations from the Bay of Bengal of the Orissa coast having different morphological features were studied. The content of linear saturated acids was 30.25 % in Phycopsis sp. 1, while their content reached 50.33 % in Phycopsis sp. 2. The amount of monobranched, saturated acids was 44.87 % in Phycopsis sp.1 and 38.83 % in Phycopsis sp. 2. There was more phytanic acid (7.92 %) in Phycopsis sp. 2 than in Phycopsis sp. 1 (4.06 %). The amount of 5,9-pentacosadienoic acid was found to be 5.54 % in Phycopsis sp. 1, while it was absent in Phycopsis sp. 2. Both species showed differences in their fatty acid composition and volatiles as well as in the antibacterial screening of their lipid extracts.

Identification of novel alpha-methoxylated phospholipid fatty acids in the Caribbean sponge Erylus goffrilleri

The phospholipid fatty acid composition of the Caribbean sponge Erylus goffrilleri is described for the first time. A total of 70 fatty acids with chain lengths between 13 and 29 carbons were identified in the sponge. Methyl-branched fatty acids predominated in E. goffrilleri suggesting the presence of a considerable number of bacterial symbionts. The novel fatty acids (5Z,9Z)-2-methoxy-5,9-hexadecadienoic acid, (5Z,9Z)-2-methoxy-5,9-octadecadienoic acid, (5Z,9Z)-2-methoxy-5,9-nonadecadienoic acid, and (5Z,9Z)-2-methoxy-5,9-eicosadienoic acid are described for the first time in the literature. In addition, the iso-methyl-branched fatty acids (9Z)-2-methoxy-15-methyl-9-hexadecenoic acid and (5Z,9Z)-2-methoxy-15-methyl-5,9-hexadecadienoic acid, also identified in E. goffrilleri, were identified for the first time in nature. Based on the identified metabolites it is proposed that the unprecedented biosynthetic sequence: i-17:1Delta9 --> 2-OMe-i-17:1Delta9 --> 2-OMe-i-17:2Delta5,9 might be responsible for the biosynthesis of the novel iso-alpha-methoxylated fatty acids in E. goffrilleri.

Fatty acids from lipids of marine organisms: molecular biodiversity, roles as biomarkers, biologically active compounds, and economical aspects

Because of their characteristic living environments, marine organisms produce a variety of lipids. Fatty acids constitute the essential part of triglycerides and wax esters, which are the major components of fats and oils. Nevertheless, phospholipids and glycolipids have considerable importance and will be taken into account, especially the latter compounds that excite increasing interest regarding their promising biological activities. Thus, in addition to the major polyunsaturated fatty acids (PUFA) such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, a great number of various fatty acids occur in marine organisms, e.g. saturated, mono- and diunsaturated, branched, halogenated, hydroxylated, methoxylated, non-methylene-interrupted. Various unprecedented chemical structures of fatty acids, and lipid-containing fatty acids, have recently been discovered, especially from the most primitive animals such as sponges and gorgonians. This review of marine lipidology deals with recent advances in the field of fatty acids since the end of the 1990s. Different approaches will be followed, mainly developing biomarkers of trophic chains in marine ecosystems and of chemotaxonomic interest, reporting new structures, especially those with biological activities or biosynthetic interest. An important part of this review will be devoted to the major PUFA, their relevance to health and nutrition, their biosynthesis, their sources (usual and promising) and market.

Methoxylated fatty acids in Blumeria graminis conidia

The total fatty acids (FA) composition of Blumeria graminis f.sp. tritici conidia, the causal agent of wheat powdery mildew, was analyzed as a function of their age. A total of 19 FA (C12-C24 saturated and unsaturated) and unusual methoxylated fatty acids (mFA) were detected in young, intermediate and old conidia. Two very long chain methoxylated FA were identified by GC-MS as 3-methoxydocosanoic and 3-methoxytetracosanoic acids. Medium chain FA were predominant in young conidia (75%, including 13% of mFA) while very long chain fatty acids constituted the major compounds in old conidia (74%, including 30% of mFA). We have shown for the first time that the total FA composition is strongly correlated with the age of B. graminis f.sp. tritici (Bgt) conidia.

Aldose Reductase Inhibitors from the Fruiting Bodies of Ganoderma applanatum

The isolation and characterization of rat lens aldose reductase (RLAR) inhibitors from the fruiting bodies of Ganoderma applanatum were conducted. Among the extracts and fractions from G. applanatum tested, the MeOH extract and EtOAc fraction were found to exhibit potent RLAR inhibition in vitro, their IC50 being 1.7 and 0.8 microg/ml, respectively. From the active EtOAc fraction, seven compounds with diverse structural moieties were isolated and identified as D-mannitol (1), 2-methoxyfatty acids (2), cerebrosides (3), daucosterol (4), 2,5-dihydroxyacetophenone (5), 2,5-dihydroxybenzoic acid (6), and protocatechualdehyde (7). Among them, protocatechualdehyde (7) was found to be the most potent RLAR inhibitor (IC50=0.7 microg/ml), and may be useful for the prevention and/or treatment of diabetic complications.

New acetylenic acids from the marine sponge Stelletta species

Four new acetylenic acids were isolated from the marine sponge Stelletta sp. by bioactivity-guided fractionation. The planar structures were established on the basis of NMR and MS analysis. The stereochemistry was defined by combined use of CD spectroscopy and a chiral anisotropic reagent, phenylglycine methyl ester (PGME). The compounds were evaluated for cytotoxicity against a small panel of five human tumor cell lines and exhibited marginal to moderate cytotoxicity.

5,9,23-Triacontatrienoic methyl ester, an elastase inhibitor from the marine sponge Chondrilla nucula

A polyethylenic fatty ester was isolated from the marine sponge Chondrilla nucula. The structure was elucidated through NMR spectral data and MS analysis as 5,9,23-triacontatrienoic methyl ester 1. Compound 1 is an elastase inhibitor [ID50 = 10 microg/mL (2 x 10(-5) M)].

New advances in the chemistry of methoxylated lipids

Methoxylated lipids have been reviewed emphasizing the alkylglycerol ethers and fatty acids bearing the methoxy group in the alkyl chain. The literature on methoxylated lipids and their derivatives has been divided into four main groups, namely 2-methoxylated alkyl glycerols, omega-methoxylated fatty acids, mid-chain methoxylated fatty acids, and alpha-methoxylated fatty acids. The natural occurrence, biological activity, and synthesis of this interesting group of lipids are discussed. Most of these compounds have been isolated from either bacterial or marine sources, but others are mainly of synthetic origin. Among the interesting biological activities displayed by these compounds the most important are antibacterial, antifungal, antitumor, and antiviral.

Total synthesis of 2-methoxy-14-methylpentadecanoic acid and the novel 2-methoxy-14-methylhexadecanoic acid identified in the sponge Agelas dispar

The phospholipid FA composition of the Caribbean sponge Agelas dispar was revisited and 40 different FA were identified. Among these a novel 2-methoxylated FA, namely, the anteiso methyl-branched 2-methoxy-14-methylhexadecanoic acid, was identified together with the recently discovered iso methyl-branched 2-methoxy-14-methylpentadecanoic acid and the normal-chain 2-methoxytetradecanoic acid. The structures of the iso and anteiso methyl-branched 2-methoxylated FA were confirmed by total syntheses, which were accomplished in seven steps and in 45-48% overall yields. Other phospholipid FA identified in A. dispar include the unusual methyl-branched 10,13-dimethyltetradecanoic acid, 3,7,11,15-tetramethylhexadecanoic (phytanic) acid, and the 11-methyloctadecanoic acid. In addition, the delta5,9 FA (5Z,9Z)-15-methyl-5,9-hexadecadienoic acid and (5Z,9Z)-5,9-octadecadienoic acid were characterized. These findings establish alternative FA biosynthetic possibilities for these marine organisms.

Novel methoxylated FA from the Caribbean sponge Spheciospongia cuspidifera

The delta6 monoenoic methoxylated FA (6Z)-2-methoxy-6-heptadecenoic acid and (6Z)-2-methoxy-6-octadecenoic acid were identified for the first time in nature in the phospholipids from the uncommon Caribbean sponge Spheciospongia cuspidifera. These findings expand the occurrence of A6 2-methoxylated FA to C17-C18 chain lengths and establish a new FA biosynthetic possibility for these marine organisms. The novel methoxylated FA also could have originated from the phospholipids of a bacterium in symbiosis with the sponge.

A new cytotoxic fatty acid (5Z,9Z)-22-methyl-5,9-tetracosadienoic acid and the sterols from the far eastern sponge Geodinella robusta

A new fatty acid, (5Z,9Z)-22-methyl-5,9-tetracosadienoic acid (1a), and a rare fatty acid, (5Z,9Z)-23-methyl-5,9-tetracosadienoic acid (2a), the predominant constituents of the free fatty acid fraction from the lipids of the sponge Geodinella robusta, were isolated and partly separated by reversed phase high-performance liquid chromatography, followed by multifold crystallization from MeOH to give 1a and 2a in 70% and 60% purity, respectively. These fatty acids were identified as (5Z,9Z)-22- and (5Z,9Z)-23-methyl-5,9-tetracosadienoic acids by nuclear magnetic resonance techniques, including distortionless enhancement by polarization transfer, heteronuclear multiple quantum connectivity, and correlation spectroscopy experiments, as well as from mass-spectrometric data for their methyl esters, the methyl esters of their perhydro derivatives, and their pyrrolidides. Mixtures of 1a and 2a showed cytotoxic activity against mouse Ehrlich carcinoma cells and a hemolytic effect on mouse erythrocytes. The sterol fraction from the same sponge was analyzed by gas-liquid chromatography-mass spectrometry, and 24-methylenecholesterol was identified as a main constituent of this fraction. The implications of the co-occurrence of membranolytic long-chain fatty acids and 24-methylenecholesterol as a main membrane sterol are discussed in terms of the phenomenon of biochemical coordination.

New methoxylated fatty acids from the Caribbean sponge Callyspongia fallax

The saturated 2-methoxylated fatty acids 2-methoxytetradecanoic acid (1), 2-methoxypentadecanoic acid (2), and 2-methoxyoctadecanoic acid (3) as well as the Delta6 monoenoic methoxylated fatty acids (6Z)-2-methoxy-6-tetradecenoic acid (4), (6Z)-2-methoxy-6-pentadecenoic acid (5), and (6Z)-2-methoxy-13-methyl-6-tetradecenoic acid (7) were identified for the first time in nature in the phospholipids from the Caribbean sponge Callyspongia fallax. These findings expand the occurrence of 2-methoxylated fatty acids to C14-C15 chain lengths and establish new fatty acid biosynthetic possibilities for marine organisms. The novel methoxylated fatty acids could have originated from the phospholipids of a bacterium in symbiosis with the sponge.

Additional bioactive Lyso-PAF congeners from the sponge Spirastrella abata

A known (1) and four new (2--5) lyso-PAF (platelet activating factor) derivatives were isolated from the sponge Spirastrella abata. Two of them are unprecedented in having a methoxy group at C-2'. The structures have been determined by combined spectroscopic methods. Their inhibitory effect on the biosynthesis of cholesterol and cytotoxicity against human solid tumor cell lines are reported.

The first naturally occurring alpha-methoxylated branched-chain fatty acids from the phospholipids of Amphimedon complanata

The phospholipid fatty acid composition of the sponge Amphimedon complanata was reinvestigated, and the 2-methoxy-13-methyltetradecanoic acid, 2-methoxy-14-methylpentadecanoic acid, and 2-methoxy-13-methylpentadecanoic acid were identified for the first time in nature. Structure characterization was accomplished by means of gas chromatographic retention times and gas chromatography-mass spectrometry. These acids could have originated from bacteria in symbiosis with the sponge.

Facile total synthesis and antimicrobial activity of the marine fatty acids (Z)-2-methoxy-5-hexadecenoic acid and (Z)-2-methoxy-6-hexadecenoic acid

The total synthesis of the naturally occurring (Z)-2-methoxy-5-hexadecenoic acid and (Z)-2-methoxy-6-hexadecenoic acid was accomplished using as a key step Mukaiyama's trimethylsilyl cyanide addition to 4- and 5-pentadecenal, respectively. These syntheses further confirm the structures of the natural marine fatty acids and corroborate their cis double-bond stereochemistry. The title compounds were antimicrobial against the Gram-positive bacteria Staphylococcus aureus (MIC 0.35 micromol/mL) and Streptococcus faecalis (MIC 0.35 micromol/mL).

Identification of 2-methoxyhexadecanoic acid in amphimedon compressa

The phospholipid fatty acid composition of Amphimedoncompressa was reinvestigated and the 2-methoxyhexadecanoic acid was identified for the first time in nature. Structure characterization was accomplished by means of gas chromatography-mass spectrometry and total synthesis from commercially available 2-hydroxyhexadecanoic acid.

New unsaturated long-chain fatty acids in the phospholipids from the Axinellida sponges Trikentrion loeve and Pseudaxinella cf. lunaecharta

In order to identify new structures and especially those involved as biosynthetic intermediates, the fatty acid composition of whole phospholipids from two Senegalese marine sponges from the order Axinellida, Trikentrion loeve and Pseudaxinella cf. lunaecharta, has been investigated by analytical gas chromatography and gas chromatography/mass spectrometry. Several new fatty acids were identified as methyl esters and N-acyl pyrrolidides, namely 16-eicosenoic, 11-tetracosenoic, 5-pentacosenoic, 11-hexacosenoic, 11-octacosenoic, 23-triacontenoic, 17,21-hexacosadienoic, 19,23-octacosadienoic, 9,23-triacontadienoic, 5,9,21-hexacosatrienoic, and 5,9,25-triacontatrienoic. Trikentrion loeve and P. cf. lunaecharta contain fifteen (25.7% of the total acid mixture) and thirteen (30.4%) delta 5,9 fatty acids, respectively. Based on gas chromatography/Fourier transform infrared experiments, the double bonds were assigned the (Z) configuration. Biosynthesis of dienoic and trienoic demospongic acids possessing an n-5 or an n-7 terminal double bond is discussed.

Two novel naturally occurring alpha-methoxy acids from the phospholipids of two Caribbean sponges

The novel (5Z)-2-methoxy-5-hexadecenoic acid (1) was identified in the phospholipids of the sponge Tethya crypta while the also novel acid (6Z)-2-methoxy-6-hexadecenoic acid (2) was found in the phospholipids of the Caribbean sponge Spheciospongia cuspidifera. The methoxy-fatty acids were mainly associated with phosphatidylethanolamine. The double bond positions were determined by gas chromatography/mass spectrometry on the corresponding dimethyl-disulfide adducts and the double bond stereochemistry was ascertained by gas chromatography/Fourier transform infrared spectroscopy. The fatty acid composition of the two sponges is reported.

Cell separation of Tethya aurantia, an analytical study of embryonic and differentiated sponge cells

The cells of the sponge Tethya aurantia var. californiana were separated on a Ficoll density gradient and the fractions analyzed for cell types and their lipids. Major cell types were choanocyte, archeocyte, and symbiont. Major differences in archeocyte and choanocyte fatty acid composition were noted for 20:4, 26:1 and 26:2. The fatty acids 26:1, 26:2, and 28:3 were dominant in the phosphatidylcholine fraction. Archeocytes had highest concentrations of 4,7,10,13-20:4 and 5,8,11,14-20:4 (arachidonic) acids which could be derived from symbionts, as odd-chain and methyl-branched fatty acid were also present. Sterol analyses showed cholesterol as a major sterol of the sponge cell fractions and clionasterol (or its 24-isomer) as a major sterol in symbiont cells.

Identification of the new 18-hexacosenoic acid in the sponge Thalysias juniperina

The phospholipid fatty acids from the sponge Spheciospongia cuspidifera were studied revealing the presence of the rare 10-octadecenoic acid (10-18:1) and a new 2-methoxyhexadecenoic acid. The phospholipid fatty acids from Thalysias juniperina were also studied revealing the presence of the hitherto unreported 18-hexacosenoic acid (18-26:1). These results tend to indicate that the biosynthetic pathway from 10-18:1 to 18-26:1 may be operative in nature. The phospholipid mixture from the sponges was also analyzed by 31P-NMR and shown to mainly consist of phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Phosphatidylcholine was not found in the sponges analyzed in this work.

The distribution of lipids and sterols in cell types from the marine sponge Pseudaxinyssa sp

The sponge Pseudaxinyssa sp., unique in sterol and fatty acid composition, was cellularly dissected into fractions enriched in each of the major cell types present in the sponge: microbial symbionts (cyanobacteria), small sponge cells (pinacocytes and choanocytes), and large sponge cells (archeocytes and cyanophytes). Three phototrophic microbial symbionts were also isolated from the cell fractions and grown in culture. An unsymmetrical distribution of fatty acids and sterols was observed for the sponge cells: small cells contained larger quantities of long chain fatty acids (greater than C24) and smaller quantities of sterols than were present in the larger sponge cells. Moreover, the rare sterols 24-isopropylcholesterol predominated in the smaller sponge cells, whereas its 22-dehydro analog predominated in the larger sponge cells. Long chain fatty acids and sterols were not detected in the cultured microbial symbionts. This constitutes the first report of lipid variability according to cell type for this most primitive group of Metazoa.

On the isolation of 2-hydroxydocosanoic and 2-hydroxytricosanoic acids from the marine sponge Amphimedon compressa

The first alpha-hydroxy fatty acids from a marine sponge, namely 2-hydroxydocosanoic and 2-hydroxytricosanoic, were identified in the Caribbean sponge Amphimedon compressa. These acids were found to occur in phosphatidylethanolamine and phosphatidylserine and constituted 52% of the total fatty acid mixture of this sponge. The long chain fatty acids 5,9,23-nonacosatrienoic (29:3) and 5,9,23-tricontatrienoic (30:3), as well as a new tetratricontatetraenoic (34:4) acid, were also found in A. compressa.

Fatty acids as biological markers for bacterial symbionts in sponges

Analyses of fatty acids with carbon numbers between C12 and C22 are reported for five Great Barrier Reef sponges. These analyses indicate that phototrophic cyanobacterial symbionts (blue-green algae) present in three of the sponges are chemically distinct, whereas the other two sponges do not contain cyanobacterial symbionts. All the sponges contain other, nonphototrophic bacteria. The fatty acid analyses indicate that the non-phototrophic bacterial populations present in the different sponges are distinct in both their chemical compositions and their abundances. Nonphototrophic bacteria are estimated to account for between 60 and 350 micrograms/g (extractable fatty acids:tissue wet weight), whereas cyanobacteria account for between 10 and 910 micrograms/g. One sponge (Pseudaxinyssa sp.) contains a relatively large amount of the isoprenoid acid, 4, 8, 12-trimethyltridecanoic acid; this acid is presumed to be derived from phytol, a degradation product of chlorophyll. This sponge also contains relatively large amounts of the nonmethylene interrupted fatty acid, octadeca-5,9-dienoic acid. Analyses of interior and cyanobacteria-rich surface tissues of this sponge indicate that these two acids are probably not associated with the symbiotic cyanobacteria.

Cell membrane localization of sterols with conventional and unusual side chains in two marine demosponges

Subcellular fractionation by differential centrifugation was performed on two previously unstudied marine sponges that predominantly contain either conventional (Reniera sp.) or unconventional (Pseudaxinyssa sp.) sterols. Direct evidence for the presence of unconventional sterols with C24 alkylated side chains in the cellular membranes of Pseudaxinyssa sp. is provided, but the presence of unconventional sterols in sponge membranes is shown not to be a universal feature of the Porifera. Possible structural and functional roles of unconventional lipid molecules in sponge cell membranes are discussed.

Cell membrane localization of long chain C24-C30 fatty acids in two marine demosponges

Subcellular fractionation by differential centrifugation was performed on two previously unstudied marine sponges (Reniera sp. and Pseudaxinyssa sp.) that represent both major subclasses of the Demospongiae. Long chain fatty acids (LCFA) with 24-30 carbon units were found as major constituents of cell membrane isolates of both sponges. Most LCFA were polyunsaturated and were constituents of the phospholipids, which are typical membrane lipids, and in particular the amino-phospholipids. The LCFA composition of phospholipids from whole sponge tissue was shown to provide a reliable indication of the LCFA composition of cell membrane phospholipids in the sponges studied. An unusual triply branched C16 isoprenoid fatty acid, 4,8,12-trimethyltridecanoic acid, also was identified as a cell membrane acid in the sponge Pseudaxinyssa sp.

High performance liquid chromatography and fast atom bombardment mass spectrometry of unusual branched and unsaturated phospholipid molecular species

The unusual symmetrical molecular species 1,2-di-3,7,11,15-tetramethylhexadecanoyl-sn-glycero-3-phosphoglyce rol, 1,2-di-5,8,11,14-docosatetraenoyl-sn-glycero-3-phosphocholine, 1,2-di-5,9,19-octacosatrienoyl-sn-glycero-3-phosphoethanolamine, and 1,2-di-5,9,23-triacontatrienoyl-sn-glycero-3-phosphoethanolamine were isolated from the marine sponges Axinella verrucosa, Higginsia tethyoides, Tethya aurantia and Aplysina fistularis by HPLC and studied by fast atom bombardment (FAB) mass spectrometry. In addition to molecular weights, branching and double bonds were located in the fatty acyl chains of the intact phospholipid molecules, using FAB either in a positive or negative mode. Some mass spectral results were obtained on enriched phospholipid fractions rather than pure molecular species using MS/MS.