Inhibited Oxidation of Lipids I: Complex Estimation and Comparison of the Antioxidative Properties of Some Natural and Synthetic Antioxidants

The activity A of antioxidants, representing a ratio between the stabilization factor F and the decrease in oxidation rate after the introduction of an inhibitor DOR (A = F/DOR) is proposed for a complex estimation of the effect of antioxidants. The specific changes in F, DOR and A are discussed in association with the participation of the inhibitor molecule and the radical formed from it in the different reactions of initiation and propagation of the chains. Several types of antioxidants (α-tocopherol, ferulic acid, BHT and BHA) in concentrations ranging from 0.02 – 0.20 wt% are investigated during the oxidation of lard at 100°C. It is established that at concentrations of 0.02–0.05 wt% the antioxidative activity increases in the sequence ferulic acid < BHT < BHA <α-tocopherol. At high concentrations (above 0.10 wt%) the activity increase follows the sequence α-tocopherol < BHT < BHA < ferulic acid. Enhancement of the antioxidant concentration above 0.02 wt% is expedient only in the case of ferulic acid. The molecules of α-tocopherol, BHA and BHT participate not only in chain termination but also in first order rate side reactions with respect to the inhibitor, which explains the decrease in their efficiency with rising concentration. The molecule of ferulic acid does not participate in side reactions. The aroxyl radical formed from BHT does not participate in chain propagation, whereas the radicals of BHA and ferulic acid take part in such reactions. The aroxyl radical of α-tocopherol joins in more than one side reactions.     

On the Participation of Fatty Alcohols in Inhibited Oxidation of Lipids

The effect of 1-tetradecanol and 1-octadecanol in concentration of (0.5-9.0)·10^?2 mol/l on the hydroquinone (1.10^?4 mol/l)-inhibited oxidation of the triacylglycerols of sunflower and olive oils at 80° and 110°C has been investigated along with the role of temperature changes within the range 23°-100°C. It is established that fatty alcohols accelerate the inhibited oxidation of lipids by participating in (i) the blocking of the phenolic antioxidant through the formation of a hydrogen bond-based complex and (ii) the proceeding of additional reactions such as chain propagation, chain branching and chain termination. The alcohol with a shorter chain length leads to the formation of a complex where the bond with the inhibitor is stronger whereas the alcohol with a longer chain length exhibits a higher activity in the elementary reactions of propagation, branching and termination of chains. The type of the lipid substrate is found to cause no qualitative change of the effect of alcohols. It is established that with increasing unsaturation (oxidizability) degree of the lipid substrate the effect of fatty alcohols on the inhibitor efficiency and the rate of inhibiting oxidation increase. The change of temperature has a specific effect on the contribution of the two alcohols to the decrease of the inhibitor efficiency and the increase in the rate of the inhibited process.     

Non-methylene Interrupted and Hydroxy Fatty Acids in Polar Lipids of the Alga Grateloupia turuturu Over the Four Seasons

Phospholipids (PL) and glycolipids (GL) FA in the edible Rhodophyta Grateloupia turuturu, from Brittany, France, were investigated over four seasons. The major lipid class was GL in all seasons (around 45 %). More than 80 FA occurred in polar lipids, with chains from C₁₂ to C₂₆, identified as methyl esters and N-acyl pyrrolidides by gas chromatography–mass spectrometry (GC–MS). PUFA occurred at up to 47.1 % (summer) in PL, and up to 43.6 % (summer) in GL. The major PUFA were 20:5n-3 (12.2 % in PL and 29.0 % in GL) and 20:4n-6 (25.6 % in PL and 10.4 % in GL). The unusual 18:3n-7 acid was identified in PL up to 2.2 %. Several minor unsaturated FA were identified in PL and are previously unreported in seaweeds, namely 14-tricosenoic, 15-tetracosenoic, 5,11-octadecadienoic and 5,9-nonadecadienoic. Also unprecedented in seaweeds, ten 2-hydroxy and three 3-hydroxy FA occurred mainly in PL, 13.9 % in spring with the 3-hydroxyhexadecanoic acid as the major one (8.1 % winter). Three n-9 monounsaturated 2-hydroxy FA occurred in PL. The 2-hydroxy-15-tetracosenoic acid was characterized as the dimethyl disulfide adduct of its methyl ester. The 2-hydroxy-16-pentacosenoic and 2-hydroxy-17-hexacosenoic acids were identified by comparison of mass spectra and GC mobilities with those of the 2-hydroxy-15-tetracosenoic acid, and of other homogeneous FA series. These rare n-9 monounsaturated 2-hydroxy FA are unprecedented in seaweeds.     

Electrochemical Oxidation of Benzoic Acid Derivatives on Boron Doped Diamond: Voltammetric Study and Galvanostatic Electrolyses

The electrochemical oxidation of aqueous wastes polluted with benzoic and salicylic acids and phthalic anhydride on boron‐doped diamond electrodes has been studied. The complete mineralization of the organic waste has been obtained in each case regardless of the nature of the compound, composition of the solution, and current density. Different voltammetric behaviors between benzoic acid, salicylic acid, and phthalic anhydride were obtained in the voltammetric study, but no differences in the electrochemical oxidation of the three compounds seems to exist in the bulk electrolyses study. The total mineralization of the three compounds at different current densities confirms that the oxidation must occur directly on the electrode surface and/or by hydroxyl radicals generated by decomposition of water and/or by other oxidants electro‐generated from the sulfate oxidation.     

Chemical Synthesis of Rare Natural Bile Acids: 11α‐Hydroxy Derivatives of Lithocholic and Chenodeoxycholic Acids

A method for the preparation of 11α‐hydroxy derivatives of lithocholic and chenodeoxycholic acids, recently discovered to be natural bile acids, is described. The principal reactions involved were (1) elimination of the 12α‐mesyloxy group of the methyl esters of 3α‐acetate‐12α‐mesylate and 3α,7α‐diacetate‐12α‐mesylate derivatives of deoxycholic acid and cholic acid with potassium acetate/hexamethylphosphoramide; (2) simultaneous reduction/hydrolysis of the resulting △¹¹‐3α‐acetoxy and △¹¹‐3α,7α‐diacetoxy methyl esters with lithium aluminum hydride; (3) stereoselective 11α‐hydroxylation of the △¹¹‐3α,24‐diol and △¹¹‐3α,7α,24‐triol intermediates with B₂H₆/tetrahydrofuran (THF); and (4) selective oxidation at C‐24 of the resulting 3α,11α,24‐triol and 3α,7α,11α,24‐tetrol to the corresponding C‐24 carboxylic acids with NaClO₂ catalyzed by 2,2,6,6‐tetramethylpiperidine 1‐oxyl free radical (TEMPO) and NaClO. In summary, 3α,11α‐dihydroxy‐5β‐cholan‐24‐oic acid and 3α,7α,11α‐trihydroxy‐5β‐cholan‐24‐oic acid have been synthesized and their nuclear magnetic resonance (NMR) spectra characterized. These compounds are now available as reference standards to be used in biliary bile acid analysis.     

Solid-Gas Reactions. Part IV the Effect of Light on the Bromination of Some Solid Cinnamic Acids

Light slows down the rate of reaction of gaseous bromine with some solid cinnamic acids. An explanation of the effect is given.     

Hydroxy Sulfonated Fatty Acid Esters as Surface Active Agents II: Surfactants from Individual Saturated and Unsaturated Fatty Acids

Hydroxy sulfonated fatty acid ester surfactants, having the general formula RCOOCH₂CHOHCH₂SO₃M (where M is alkali or other metal) have been synthesized from four saturated (C₁₂ to C₁₈) and four unsaturated (C₁₈?, C₁₈²?, C₁₈³? and ricinoleic) fatty acids. Comparative evaluation of their surface active properties as well as some analytical methods for determining their composition and their identification and separation have been described.     

新型捕剂二烃基硫代次膦酸的合成及起泡性能

报道了一类新型捕收剂二烃基硫代次膦酸的合成，即Ｒ２ＰＳＯＨ（Ｒ＝戊基、异戊基、环己基、苯基）。并对这类化合物的起泡性能作了研究，提出了泡沫消失动力学方程，对化合物结构与起泡性关系进行了讨论。     

Novel Nickel(II), Palladium(II), and Platinum(II) Complexes with O,S Bidendate Cinnamic Acid Ester Derivatives: An In Vitro Cytotoxic Comparison to Ruthenium(II) and Osmium(II) Analogues

(1) Background: Since the discovery of cisplatin’s cytotoxic properties, platinum(II) compounds have attracted much interest in the field of anticancer drug development. Over the last few years, classical structure–activity relationships (SAR) have been broken by some promising new compounds based on platinum or other metals. We focus on the synthesis and characterization of 17 different complexes with β-hydroxydithiocinnamic acid esters as O,S bidendate ligands for nickel(II), palladium(II), and platinum(II) complexes. (2) Methods: The bidendate compounds were synthesized and characterized using classical methods including NMR spectroscopy, MS spectrometry, elemental analysis, and X-ray crystallography, and their cytotoxic potential was assessed using in vitro cell culture assays. Data were compared with other recently reported platinum(II), ruthenium(II), and osmium(II) complexes based on the same main ligand system. (3) Results: SAR analyses regarding the metal ion (M), and the alkyl-chain position (P) and length (L), revealed the following order of the effect strength for in vitro activity: M > P > L. The highest activities have Pd complexes and ortho-substituted compounds. Specific palladium(II) complexes show lower IC₅₀ values compared to cisplatin, are able to elude cisplatin resistance mechanisms, and show a higher cancer cell specificity. (4) Conclusion: A promising new palladium(II) candidate (Pd3) should be evaluated in further studies using in vivo model systems, and the identified SARs may help to target platinum-resistant tumors.     

NMR Studies of Some Oxygenated,Halogenated and Sulphur-Containing Fatty Acids and Their Derivatives

NMR shifts for a large number of fatty epoxy, hydroxy, keto, epithio, carboxymethylthio, cis and trans ethylenic, acetylenic, bromo and chloro compounds are recorded and discussed. A 3-trans monoene present in aster seed oil could be identified. Cis and trans epoxy acids show different shifts (2.25 and 2.52 δ), and corresponding epithio acids show different shifts downfield (2.95 and 2.65 δ). The proton of a terminal acetylenic group, as in undecynoic acid, appears at 2.3 δ. 9,10,12,13-Tetrabromides (from linoleic acid) and 9,9,10,10-tetrabromides (from stearolic acid) were differentiated by the presence of triplets at 4.15 and 4.55 δ in the former.     

Direct Method of Preparation of Dodecanesulfonamide Derivatives and Some Surface Properties

Alkanesulfonamide compounds are known as surfactants because of the presence of –SO₂NH– function in their molecule. Thus, they are used in many formulations in the chemical and textile industries and also as inhibitors of corrosion. Generally, sulfonamide derivatives are prepared using sulfonyl chlorides as the raw material. The methods often described in the literature involve the use of ammonia gas and pressure. A simple and direct method to prepare pure alkanesulfonamide derivatives possessing good surface properties is presented in this work. Thus, n-dodecanesulfonyl chlorides obtained by photochemical sulfochlorination of n-dodecane under visible light using sulfuryl chloride were separated from the reaction mixture. These sulfonyl chlorides, a mixture of primary and secondary isomers, were transformed in one step into N-ethyldodecanesulfonamides, N-ethanoldodecanesulfonamides and the salts of dodecanesulfonamidoacetic acid. After purification on chromatographic column, the six position isomers of these sulphonamide derivatives were analysed and well separated by gas phase chromatography using a nonpolar column. Then, gas phase chromatography analysis coupled to mass spectrometry using electronic impact (GC/MS/IE) was performed to identify the different position isomers. The primary isomers of sulphonamide derivatives were identified by crossed injection of the compounds obtained by synthesis from the 1-chlorododecane using the Grignard reagent, and identified by IR, ¹H- and ¹³C-RMN, elementary analysis and GC/MS/IE. Some physico-chemical properties of these sulphonamide derivatives were examined. The variation of surface tension versus the concentration of both primary and secondary sulphonamide derivatives were studied, and the critical micellar concentration was determined for the compounds showing surface activity. The foaming power was also determined by the Bartsch method, and the results obtained were compared to those of a commercial surfactant, the linear alkylbenzenesulfonate. The stability of the foam formed was also evaluated.

Contents of Fatty Acids, Selected Lipids and Physicochemical Properties of Western Australian Sandalwood Seed Oil

The study was designed to characterise two extracts of Western Australian sandalwood (Santalum spicatum) seed oils for their physicochemical and lipid characteristics. Sandalwood plantation’s surplus seeds could be used for their oil content, to improve the commercial viability of this industry. The seed oils were obtained by solvent extraction and supercritical carbon dioxide extraction respectively. Important physicochemical parameters were compared with other oils commonly used in pharmaceutical and cosmetic products. Acid values were found to be higher (6.0–7.5 mg KOH/1 g oil) while peroxide values (6.7–9.0 mequiv/Kg) were lower than reported for other oils. Tocopherols were found to be lower than those usually reported for nut oils (α-tocopherol 1–3 mg/100 g; δ-tocopherol 2.2–5.7 mg/100 g), squalenes and phytosterols were found in considerable quantities. The fatty acid content consisted largely of ximenynic acid (35 %) and oleic acid (52 %). No oxidative derivatives of fatty acids were observed. Although there were statistically significant differences in some properties, the magnitude of these were insufficient to conclude there were any notable differences in the two oil extracts.     

Reactivators of Inhibited Acetylcholinesterase. II. The Preparation and Properties of Some New 4-Hydroximinomethyl-1-(N-Aminoalkyl)-Pyridinium Salts

A new series of heterocyclic oximes, prepared by the quarternization of 4-hydroximino-methylpyridine with various aminoalkyl halides, have been tested as reactivators of phosphorylated cholinesterase. With the most active member, 4-hydroximinomethyl-l-[3(N, N-dimethylamino)-n-propyl]-pyridinium chloride, the rate of reactivation is comparable to that obtained with the known diquarternary compound, TMB-4. These findings shed new light on the mechanistic concept of the reactivation process.     

Comparison of Interface and Emulsifying Activities of the Derivatives of Acetic and Acetocitric Acids and Low-grade Monoglycerides

Application possibilities of low-grade monoglycerides for preparation of diglyceride-derivatives of monoglycerides and selected non-fatty acids: acetic and acetocitric acids are described and the characteristics of the products of acylations are presented.     

Syntheses,Structures and Fluorescent Properties of Lead(II) Complexes Based on 5,6-Substituted 1,10-Phenanthroline Derivatives and Benzene Dicarboxylic Acids

Three new coordination polymers, [Pb(1,3-bdc)(MOPIP)₂]_n·nH₂O (1), [Pb(1,4-bdc)(MOPIP)]_n (2) and [Pb₂(1,4-bdc)₂(MEDPQ)₂]_n·nH₂O (3) (MOPIP = 2-(4-methoxyphenyl)-1H-imidazo[4,5-f] [1, 10] phenanthroline, MEDPQ = 2-methyldipyrido [3,2-f:2′,3′-h]quinoxaline, 1,3-H₂bdc = benzene-1,3-dicarboxylic acid, 1,4-H₂bdc = benzene-1,4-dicarboxylic acid), have been prepared through hydrothermal reactions. The transformation of coordination modes of organic carboxylate ligands and 5,6-substituted 1,10-phen derivatives has a crucial influence on the structures of these series. In compound 1, 1,3-bdc anion adopts a chelating bidentate and bridging monodentate coordination mode, which results in a hepta-coordinated environment of Pb(II) center. However, in complex 2, 1,4-bdc anion acts in the chelating bidentate mode, which results in a hexa-coordinated environment of Pb(II) center. Complex 3 shows face-to-face π···π interactions between MEDPQ and benzene rings, which are different to that of the complexes 1 and 2. The fluorescence property and thermal stability were also investigated.     

Inhibited Oxidation of Lipids III: On the Activity of Ascorbyl Palmitate during the Autoxidation of Two Types of Lipid Systems in the Presence of α-Tocopherol

The kinetic behaviours of two types of lipid systems differing in unsaturation (sunflower oil and lard) and containing 0.05% α-tocopherol are investigated in the presence of different concentrations of ascorbyl palmitate (AP) at different temperatures (25 and 100°C). The kinetic parameters (efficiency, strength and activity) of AP in the presence and absence of α-tocopherol are quantitatively discussed. It is proved that ascorbyl palmitate is not only a synergist of α-tocopherol but also a radical type inhibitor of the lipid autoxidation. It is found that the rise of temperature is associated with an increase in activity of AP in the presence of α-tocopherol, this increase being more pronounced with the lipid system of lower oxidizability.     

Refractory Castables: II, Some Properties, and Effects of Heat-Treatments

Differential thermal analyses were made and weight losses were determined up to 1000°C. for a domestic and an imported high-alumina hydraulic cement after hydrating. Refractory castables were prepared in the laboratory with these two cements and fire-clay brick and flintclay aggregates. Compressive, transverse, and tensile strengths of these castables were obtained after heating 4,8, and 12 months at 300°C. and at other temperatures up to 1350°C. for shorter periods of time. Sixteen commercial brands of castables were tested for sieve analysis, P.C.E., and flow, on the material "as received". The three types of strengths of the sixteen castables also were determined after treatments at 95% relative humidity and after heating at temperatures up to 1350°C. Some information on porosity and structural and linear changes after the heat-treatments was obtained.     

Quantification of Mixtures of C2 and C3 Hydroxy Acids and Products of Glycerol Oxidation by High-Performance Liquid Chromatography and Quantitative 13C NMR

The aim of this study was to develop an improved general method for detecting and quantifying mixtures of hydroxy acids and other products of glycerol oxidation in aqueous media, to prevent the confusions that can occur due to similarities and interactions between these compounds depending on media conditions. Standard potential products of glycerol oxidation—glycerol, glyceraldehyde, dihydroxyacetone, glyceric acid, lactic acid, glycolic acid, glyoxylic acid, oxalic acid, tartronic acid, and mesoxalic acid—were analyzed by high-performance liquid chromatography (HPLC) and quantitative ¹³C nuclear magnetic resonance (NMR), in mixtures of known composition. The results obtained were concordant with the known compositions tested. HPLC was more accurate than quantitative ¹³C NMR for simple mixtures, but ¹³C NMR was required for complex mixtures containing dihydroxyacetone and glycerol, oxalic acid and mesoxalic acid, or glyoxylic acid and tartronic acid, pairs of compounds not well separated or detected by HPLC. As proof-of-concept, an unknown mixture generated by glycerol oxidation was analyzed by HPLC and quantitative ¹³C NMR. The results obtained were concordant and allowed accurate determination of the composition of the sample, which contained mesoxalic acid as the major product, with oxalic acid, tartronic acid, and glyceric acid as by-products.