Three new and bioactive icosanoids from the temperate red marine algaFarlowia mollis

Three new dihydroxyicosanoids, 12(R),13(R)-dihydroxyicosa-5(Z), 8(Z),10(E),14(Z)-tetraenoic acid, 12(R),13(R)-dihydroxyicosa-5(Z), 8(Z),10(E),10(Z),17(Z)-pentaenoic acid and 10(R^*),11(R^*)-dihydroxyoctadeca-6(Z),8(E),12(Z)-trienoic acid, have been isolated from a previously unstudied temperate red marine alga,Farlowia mollis (Cryptonemiales, Rhodophyta). The structures of these new metabolites have been deduced from detailed nuclear magnetic resonance and mass spectrometry analyses on stabilized diacetate-methyl esters and stereochemistry deduced by¹H NMR couplings and CD analysis of a dibenzoate derivative. Collectively, these new natural products modulate fMLP-induced superoxide anion generation in human neutrophils, inhibit the conversion of arachidonic acid to lipoxygenase products by human neutrophils, and inhibit the functioning of the dog kidney Na⁺/K⁺ ATPase.     

Two unsaturated 9R-hydroxy fatty acids from the cyanobacteriumAnabaena flos-aquae f. flos-aquae

(9R-10E,12Z,15Z)-9-Hydroxyotadecatrienoic acid and (9R,10E,12Z)-9-hydroxyoctadecadienoic acid were isolated from the nitrogen fixing cyanobacteriumAnabaena flosaquae. f. flos-aquae and characterized as the corresponding methyl esters. This is the first report of the natural occurrence of 9R-oxygenated fatty acids.     

Fatty acids in phospholipids isolated from human red cells

Total lipids of packed erythrocytes from healthy men 22 to 25 years old were extracted with chloroform-methanol mixture. Phospholipid classes were separated from neutral lipids and pigments on a silicic acid column. Phosphatidyl inositol (PI) was freed of its contaminants phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) on an aluminum oxide column. Additional silicic acid columns with modified solvent systems were needed for complete separation of other overlapped phospholipid classes. The identification of phospholipids in each eluted fraction was accomplished by TLC, using the appropriate spray tests and reference compounds, and confirmed on each of the isolated phospholipids by IR spectrophotometry. The total content of phospholipids as determined by phosphorus analysis was found to be 2.63 mg/ml of packed cells. These phospholipids were found to have the following composition (in per cent of total phospholipid): PI, 2.3; PE, 13.4; ethanolamine plasmalogen (EP), 14.5; PS, 3.9; lecithin (L), 34.2; choline plasmalogen (CP), 1.4; sphingomyelin (Sph), 28.4 and lysolecithin (LL), 1.7. The fatty acid composition of each phospholipid was determined by GLC. The average number of double bonds per fatty acid in the isolated phospholipids was found to be as follows: PI, 1.5; PE, 1.9; EP, 3.6; PS, 2.1; L, 1.0; CP, 2.0; Sph, 0.2 and LL, 0.5. The positional distribution of fatty acids in both L and PE was ascertained by selective enzymatic hydrolysis with phospholipase A. Saturated fatty acids of L were esterified predominantly in the α′-position, whereas in PE only 63.9 mole per cent of the saturated fatty acids were found in this position. Presented in part at the AOCS Meeting in Los Angeles, April 1966. Dept. of Health, Education and Welfare, USPHS.     

Two novel phospholipid fatty acids from the caribbean spongeGeodia gibberosa

The novel fatty acids (Z)-6-nonadecenoic acid (1) and (Z)-17-pentacosenoic acid (2) were characterized in the spongeGeodia gibberosa. These fatty acids were mainly found in phosphatidylethanolamine and phosphatidylcholine.     

Novel oxylipins from the temperate red alga polyneura latissima: Evidence for an arachidonate 9(S)-lipoxygenase

The oxylipin chemistry of the temperate red alga Polyneura latissima has been investigated. The structures of three novel oxylipins, 8-[1′(Z),3′(Z),6′(Z)-dodecatriene-1′-oxyl-5(Z),7(E)-octadienoic acid, 7(S ^*)-hydroxy-8(S ^*),9(S ^*)-epoxy-5(Z), 11(Z),14(Z)-eicosatrienoic acid, 7(R ^*)-hydroxy-8(S ^*), 9(S ^*)-epoxy-5(Z), 11(Z),14(Z)-eicosatrienoic acid, together with two known eicosanoids, 9(S)-hydroxy-5(Z), 7(E), 11(Z), 14(Z)-eicosatetraenoic acid, and 9, 15-dihydroxy-5(Z),7(E),11(Z),13(E)-eicosatetraenoic acid, were elucidated by spectroscopic methods and chemical degradation. The oxygenation pattern of these oxylipins suggests that P. latissima metabolizes polyunsaturated fatty acids via a 9(S)-lipoxygenase.     

Fine-scale variability of lanosol and its disulfate ester in the temperate red algaNeorhodomela larix

Aqueous extraction and HPLC separation techniques were used to quantify two major bromophenols naturally present in the red algaNeorhodomela larix: lanosol (2,3-dibromo-4,5-dihydroxybenzyl alcohol) and its 1,4-disulfate ester. Maximum concentrations of each compound were as high as 1.5% on a wet mass basis. The within-plant distributions of lanosol and its ester were highly variable on centimeter scales: adjacent portions often varied by an order of magnitude in bromophenol content. Some bromophenol variation was related to algal phase, location within the algal thallus, and reproductive status. Bromophenol concentrations were higher in exterior vegetative regions and some reproductive structures (cystocarps and tetrasporangial branchlets) than in interior vegetative regions or male reproductive structures (spermatangial stichidia). In contrast to results reported for harvestedN. larix, there was no evidence that the intactin situ algae released either compound into seawater.     

The preparation of hydroxystearic acids from red oil (Commercial oleic acid)

The hydroacetoxylation of red oil (commercial oleic acid) in acetic acid solution has been studied. The optimum hydroacetoxylation conditions were obtained under anhydrous conditions using sulphuric acid as a catalyst at:

1. 1.
   a concentration of 1% (based on the wt of red oil).     
   
   

The isomeric structure of the C18 unsaturated acids from their raman and infra red spectra

Summary Infra-Red and Raman spectroscopic examination of the unsaturated C₁₈ fatty acids leads to the conclusion that the naturally occurring acids such as oleic, linoleic and linolenic contain only cis double bond linkages, while the artificial elaidic and linelaidic acids contain only the trans linkages.     

Two novel naturally occurring α-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 spongeTethya crypta while the also novel acid (6Z)-2-methoxy-6-hexadecenoic acid (2) was found in the phospholipids of the Caribbean spongeSpheciospongia 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.     

A new eicosapentaenoic acid formed from arachidonic acid in the coralline red algaeBossiella orbigniana

Aqueous extracts of the coralline red algaeBossiella orbigniana have been shown to catalyze the enzymatic oxidation of arachidonic acid to a previously unreported ω6 eicosapentaenoic acid product. This unique fatty acid contains a conjugated tetraene with absorption maxima at 293, 306, and 321 nm, and was identified by spectral methods as 5(Z),8(Z),10(E),12(E),14(Z)-eicosapentaenoic acid. The compound was given the trivial name bosseopentaenoic acid. Under experimental conditions, production of bosseopentaenoic acid was linear up to 2 hr and dioxygen was consumed. Bosseopentaenoic acid, along with several other conjugated tetraenes, was also present in the algae endogenously as revealed by a comparison of the ultraviolet (UV) spectra and the high-performance liquid chromatographic (HPLC) pattern of the purified product and the organic extract ofBossiella.     

红甘蓝色素稳定性的研究

研究了红甘蓝色素的稳定性。实验证明 :在酸性条件下该色素对阳光、热和部分金属离子有很好的稳定性 ;对食品加工中常用氧化剂和还原剂也比较稳定。     

Nonlinear biodegradable polyanhydrides synthesized from natural fatty acids through a new way

Ricinoleic acid was esterified by fatty diacid chlorides to yield intermediate diacids, which were next converted to corresponding polyanhydrides by vacuum-melt polycondensation. The intermediates and polymers were characterized by means of ¹H NMR, IR spectroscopy, differential scanning calorimetry (DSC), X-Ray diffraction and light scattering. The optimized reaction conditions of melt polycondensation were investigated and copolyanhydride with molecular weight (weight average) up to 1.38 × 10⁵ and intrinsic viscosity of 126 cm³/g was obtained. DSC and X-ray diffraction analysis showed that the synthesized copolyanhydrides exhibited much lower crystallinity and improved thermal properties in comparison with aliphatic linear homopolyanhydrides. Received: 8 October 1996/Revised: 14 April 1997/Accepted: 22 April 1997     

Alpha-aminoxy acids: new possibilities from foldamers to anion receptors and channels

Naturally occurring peptides serve important functions as enzyme inhibitors, hormones, neurotransmitters, and immunomodulators in many physiological processes including metabolism, digestion, pain sensitivity, and the immune response. However, due to their conformational flexibility and poor bioavailability, such peptides are not generally viewed as useful therapeutic agents in clinical applications. In an effort to solve these problems, chemists have developed peptidomimetic foldamers, unnatural oligomeric molecules that fold into rigid and well-defined secondary structures mimicking the structures and biological functions of these natural peptides. We have designed peptidomimetic foldamers that give predictable, backbone-controlled secondary structures irrespective of the nature of the side chains. This Account presents our efforts to develop a novel class of peptidomimetic foldamers comprising alpha-aminoxy acids and explore their applications in the simulation of ion recognition and transport processes in living systems. Peptides constructed from alpha-aminoxy acids fold according to the following rules: (1) A strong intramolecular eight-membered-ring hydrogen bond forms between adjacent alpha-aminoxy acid residues (the alpha N-O turn). The chirality of the alpha-carbon, not the nature of the side chains, determines the conformation of this chiral N-O turn. (2) While homochiral oligomers of alpha-aminoxy acids form an extended helical structure (1.8 8 helix), heterochiral ones adopt a bent reverse turn structure. (3) In peptides of alternating alpha-amino acids and alpha-aminoxy acids, the seven-membered-ring intramolecular hydrogen bond, that is, the gamma-turn, is initiated by a succeeding alpha N-O turn. Thus, this type of peptide adopts a novel 7/8 helical structure. In investigating the potential applications of alpha-aminoxy acids, we have found that the amide NH units of alpha-aminoxy acids are more acidic than are regular amide NH groups, which makes them better hydrogen bond donors when interacting with anions. This property makes alpha-aminoxy acids ideal building blocks for the construction of anion receptors. Indeed, we have constructed both cyclic and acyclic anion receptors that have strong affinities and good (enantio-)selectivities toward chloride (Cl(-)) and chiral carboxylate ions. Taking advantage of these systems' preference for Cl(-) ions, we have also employed alpha-aminoxy acid units to construct a synthetic Cl(-) channel that can mediate the passage of Cl(-) ions across cell membranes. Continued studies of these peptidomimetic systems built from alpha-aminoxy acids should lead to a broad range of applications in chemistry, biology, medicine, and materials science.     

Synthesis of new polyester polyols from epoxidized vegetable oils and biobased acids

Biobased polyols were synthesized from reaction between epoxidized soybean oil and lactic, glycolic, or acetic acids. Polyols were characterized by NMR, alcohol and acid titration, and SEC. These analyses allowed to determine an average hydroxyl functionality between 4 and 5, with an oligomer content close to 50 wt%. Synthesized polyols were formulated with isocyanate to yield polyurethanes (PUs). Thermal and mechanical properties of obtained materials showed that synthesized polyols lead to rigid and brittle material with Young moduli higher than 900 N/mm² at RT and with T_g values around 50°C. Practical application: The products of the chemistry described in this contribution, i.e.: polyol from vegetable oils and lactic, glycolic, or acetic acids, provide biobased building blocks for further PUs syntheses by reaction with diisocyanates. The obtained PUs are partially biobased and may be applied as binders and coatings.     

Unsaturated fatty acids. I. Low temperature urea complexes of polyunsaturated acids from bovine tissue

Summary A mixture of fatty acids obtained from autolyzed saline extracts of beef testicular tissue was fractionated by crystallization of the urea complexes at 5°, −20°, and −75°C. Fractions rich in docosahexaenoic and in arachidonic acids were obtained as solid complexes. The filtrate remaining after precipitation of the solid urea complexes contained a high percentage of hexaenoic acid of shorter chain length than docosahexaenoic, probably eicosahexaenoic acid. Presented at the fall meeting of the American Oil Chemists' Society, Minneapolis, Oct. 11–13, 1954. Presented in part before the Lipoid Section, IId International Congress of Biochemistry, Paris, France, Sept. 21, 1952.     

Humic acids from lignite. 2. Alkaline permanganate oxidation

The potassium permanganate oxidation of methylated humic acid from a Spanish lignite yielded mainly straight-chain alkanes together with a mixture of fatty acids, methyl straight-chain alkyl ketones, aliphatic dicarboxylic, phenolic and benzenecarboxylic acids. Furthermore, some unusual compounds such as dehydroabietic and bromohydroxybenzoic acids and bis(2-ethylhexyl)phthalate were also identified. Although the analytical characteristics permit them to be included within the concept of humic acids, the oxidation products are closer to those from organic geochemical substances such as kerogen.     

The production potential of eicosapentaenoic and arachidonic acids by the red algaPorphyridium cruentum

The red microalgaPorphyridium cruentum is a new source for eicosapentanoic acid (EPA) and arachidonic acid (AA) fatty acids of potential pharmaceutical value. The conditions leading to a high content of either fatty acid were investigated. The highest EPA content was obtained under conditions resulting in high growth rate (2.4% of ash free dry weight in Strain 1380-1d). High AA content was obtained under slow growth conditions and was maximal in th stationary phase or under nitrogen starvation (2.9%). Strain 1380-la had the highest content (1.9%) of arachidonic acid under exponential growth conditions. By imposing nitrogen starvation, it was possible to obtain a lipid mixture which may be separated into AA and EPA rich fractions.     

Novel brominated phospholipid fatty acids from the Caribbean spongeAgelas sp.

The very long-chain fatty acids, (5E,9Z)-6-bromo-5,9-tetracosadienoic, (5E,9Z)-6-bromo-23-methyl-5,9-tetracosadienoic, (5E,9Z)-6-bromo-5,9-pentacosadienoic and (5E,9Z)-6-bromo-24-methyl-5,9-pentacosadienoic acids, were identified in the phospholipids (mainly phosphatidylethanolamine) of the spongeAgelas sp. Structure elucidation was accomplished by means of mass spectrometry and chemical transformations, including deuteration with Wilkinson's catalyst. All of the sterols from the sponge had the Δ5,7 nucleus, with 24-methylcholesta-5,7,22-trien-3β-ol (ergosterol) and 24-ethylcholesta-5,7,22-trien-3β-ol being the most abundant.