Multiple Beneficial Lipids Including Lecithin Detected in the Edible Invasive Mollusk Crepidula fornicata from the French Northeastern Atlantic Coast

The invasive mollusk Crepidula fornicata, occurring in large amounts in bays along the French Northeastern Atlantic coasts, may have huge environmental effects in highly productive ecosystems where shellfish are exploited. The present study aims at determining the potential economic value of this marine species in terms of exploitable substances with high added value. Lipid content and phospholipid (PL) composition of this mollusk collected on the Bourgneuf Bay were studied through four seasons. Winter specimens contained the highest lipid levels (5.3% dry weight), including 69% of PLs. Phosphatidylcholine (PC) was the major PL class all year, accounting for 63.9% to 88.9% of total PLs. Consequently, the winter specimens were then investigated for PL fatty acids (FAs), and free sterols. Dimethylacetals (DMAs) were present (10.7% of PL FA + DMA mixture) revealing the occurrence of plasmalogens. More than forty FAs were identified, including 20:5n-3 (9.4%) and 22:6n-3 (7.3%) acids. Fourteen free sterols were present, including cholesterol at 31.3% of the sterol mixture and about 40% of phytosterols. These data on lipids of C. fornicata demonstrate their positive attributes for human nutrition and health. The PL mixture, rich in PC and polyunsaturated FAs, offers an interesting alternative source of high value-added marine lecithin.     

New cytotoxic oxygenated sterols from the marine bryozoan Cryptosula pallasiana

Six new sterols (1-6), together with seven known sterols (7-13), were isolated from the CCl(4) extract of the marine bryozoan Cryptosula pallasiana, four (3-6) of which have already been reported as synthetic sterols. This is the first time that these compounds (3-6) are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D) NMR and HR-ESI-MS data. Compounds 1-4, 7 and 10-13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC(50) values from 14.73 to 22.11 μg/mL except for compounds 12 and 13.     

Analysis of free phytosterols/stanols and their intact fatty acid and phenolic acid esters in various corn cultivars

The contents and the compositions of free sterols/stanols, steryl/stanyl fatty acid esters and steryl/stanyl phenolic acid esters were determined in 25 corn cultivars grown at the same location and in the same year. The lipid extracts obtained from the flours of whole kernels were subjected to solid-phase extraction for the isolation and separation of the sterol classes, followed by capillary gas chromatography. The study provides for the first time information on the variability of individual steryl/stanyl fatty acid esters in corn cultivars. The analysis revealed pronounced differences in total contents of each sterol class. The levels of free sterols/stanols ranged from 298 to 433 μg/g dry matter flour, those of steryl/stanyl fatty acid esters from 430 to 1187 μg/g and those of steryl/stanyl phenolic acid esters from 46 to 240 μg/g. Free sterols/stanols were mainly composed of sitosterol and campesterol; up to 11% were made up of stanols. Steryl/stanyl esters of C18-fatty acids were dominating, with sitosteryl linoleate as the most abundant ester (44.7–53.5% of total fatty acid esters). Among the three investigated sterol classes, the distribution patterns of steryl/stanyl phenolic acid esters showed the greatest variability between the cultivars, even though trans-sitostanyl ferulate was the dominating ester in all samples.     

Polyoxygenated Sterols from the South China Sea Soft Coral Sinularia sp

Chemical investigation of the ethanol extract of soft coral Sinularia sp. collected from the South China Sea led to the isolation of three new polyoxygenated sterols, (3S,23R,24S)-ergost-5-ene-3β,23α,25-triol (1), (24S)-ergostane-6-acetate-3β,5α,6β,25-tetraol (2), (24S)-ergostane-6-acetate-3β,6β,12β,25-tetraol (3) together with three known ones (4-6). The structures, including relative configurations of the new compounds (1-3), were elucidated by detailed analysis of spectroscopic data (IR, UV, NMR, MS) and by comparison with related reported compounds. The absolute configuration of 1 was further determined by modified Mosher's method. Compound 5 exhibited moderate cytotoxicity against K562 cell line with an IC(50) value of 3.18 μM, but also displayed strong lethality toward the brine shrimp Artemia salina with a LC(50) value of 0.96 μM.     

微波技术对油菜籽品质影响研究进展

微波技术作为一种高效的加工手段,在菜籽加工过程中的应用逐渐引起了关注。菜籽压榨前微波预处理能将菜籽油中油菜籽多酚含量提高近120倍之多,菜籽油中植物甾醇、维生素E的含量也能得到显著提升。此外,微波预处理还能加速硫甙的降解,与传统炒籽预处理相比,微波菜籽油香味更浓郁丰富。本文围绕微波技术在油菜籽加工领域的应用展开论述。     

Effects of imazalil on sterol composition of sensitive and DMI-resistant isolates of Penicillium italicum

Imazalil differentially inhibited dry weight increase of 10-hour-old germlings of wild-type and DMI-resistant isolates ofPenicillium italicum in liquid malt cultures. EC₅₀ values ranged from 0.005 to 0.27 g ml^–1. In all isolates ergosterol constituted the major sterol (over 95% of total sterols) in the absence of the fungicide. Therefore, DMI-resistance cannot be associated to a deficiency of the C-14 demethylation enzyme in the ergosterol biosynthetic pathway. Imazalil treatment at concentrations around EC₅₀ values for inhibition of mycelial growth resulted in a decrease in ergosterol content and a simultaneous increase in 24-methylene-24,25-dihydrolanosterol content in all isolates. A correlation existed between the imazalil concentration necessary to induce such changes in sterol composition and the EC₅₀ values for inhibition of mycelial growth of the different isolates. The reason for the differential effects of imazalil on sterol composition in the variousP. italicum isolates may be due to decreased accumulation of the fungicide in the mycelium and to other yet non-identified mechanisms of resistance.Imazalil remt differentieel de toename in drooggewicht van 10-uur-oude gekiemde sporen van wild-type en DMI-resistente isolaten vanPenicillium italicum in vloeistofcultures van moutextract. De EC₅₀ waarden voor groei van de verschillende isolaten lopen uiteen van 0,005 tot 0,27 g ml^–1. In afwezigheid van het fungicide is in alle isolaten ergosterol het belangrijkste sterol (meer dan 95% van het totaal). DMI-resistentie kan daarom niet in verband staan met deficiëntie van het C-14 demethyleringsenzym in de ergosterol biosynthese. Imazalilbehandeling van mycelium bij concentraties rond de EC₅₀ waarde voor groeiremming, resulteerde bij alle isolaten in een afname van het ergosterolgehalte en een gelijktijdige toename van het gehalte aan 24-methyleen-24,25-dihydrolanosterol. Er bestaat dus een nauwe correlatie tussen de imazalilconcentratie die noodzakelijk is om vergelijkbare veranderingen in sterolsamenstelling te induceren en de EC₅₀ waarde voor remming van myceliumgroei van de verschillende isolaten. De differentiële effecten van imazalil op de sterolsamenstelling van de verschillendeP. italicum isolaten kunnen worden veroorzaakt door verminderde accumulatie van het fungicide in het mycelium en door andere, nog niet geïdentificeerde resistentiemechanismen.     

Effects of sterol biosynthesis inhibitor fungicides in the phytopathogenic fungus,Nectria haematococca: ergosterol depletion versus precursor or abnormal sterol accumulation as the mechanism of fungitoxicity

The relative importance of the depletion of ergosterol versus the accumulation of precursor or abnormal sterols in the mechanism of fungal growth inhibition by sterol biosynthesis inhibitor fungicides is incompletely understood. In order to investigate this problem further, the degree of inhibition of the growth of Nectria haematococca by fungicides with different enzymatic targets in the sterol biosynthetic pathway was determined and compared with their effects on the sterol profile. The sensitivity of N. haematococca was highest towards fenpropimorph, followed by tebuconazole, terbinafine, fenpropidin and tridemorph. Terbinafine, a squalene epoxidase inhibitor, induced a very large accumulation of squalene without very significant inhibition of ergosterol biosynthesis and growth. The fungus appeared able to tolerate large amounts of squalene. In the case of tebuconazole, a sterol 14α-demethylase inhibitor, it seemed that the accumulation of C4 mono- and dimethyl sterols was responsible for fungitoxicity. Fenpropimorph and fenpropidin seemed to be good inhibitors of both sterol Δ¹⁴-reductase and Δ⁸→Δ⁷-isomerase, whereas tridemorph was a better inhibitor of Δ⁸→Δ⁷-isomerase than of the Δ¹⁴-reductase. Large accumulations of Δ^8,14- or Δ⁸-sterols and correspondingly large decreases in the ergosterol content are both implicated in the fungitoxicity of these compounds in N. haematococca. © 1998 Society of Chemical Industry     

Marine co‐product meals as a substitute of fishmeal in diets for white shrimp Litopenaeus vannamei improve growth,feed intake and muscle HUFA composition

Total replacement of fishmeal using marine co‐product meals in the diets for white shrimp Litopenaeus vannamei and its effects on growth, feed utilization and muscle HUFA and sterol composition were assessed in a 45‐day feeding trial with juvenile shrimp (0.32 g mean initial weight). Eight dietary treatments were tested: a control diet containing fishmeal (FM), a commercial shrimp diet as external reference and six diets where the FM in the control diet was totally replaced by pen shell scallop viscera (Pinna rugosa), squid viscera (Dosidicus gigas) or whole chub mackerel (Scomber japonicus) meals, produced by two methods: (i) cooking followed by grinding and drying and (ii) grinding followed by drying. Survival in all treatments was above 92%, except in the commercial diet (77%). The growth response, feed utilization and chemical composition of shrimp varied among the treatments and were affected in different ways by the by‐products and the meals preparation process. Growth and feed intake were significantly higher in shrimp fed diets containing cooked‐dried squid and pen shell scallop viscera meals, and whole mackerel meal produced by grinding followed by drying. Muscle fatty acid profiles were improved for human consumption when these ingredients were used, compared with the diets containing FM.     

南极磷虾脂溶性成分的研究进展

南极磷虾脂类营养含量丰富:油脂提取物中二十碳五烯酸(EPA)含量高于15%,二十二碳六烯酸(DHA)含量高于9%,总磷脂含量高于20%,冰鲜的南极磷虾中总虾青素含量高于3 mg/100 g。本文总结了近年来国内外学者对南极磷虾油中的脂肪酸、虾青素、脂溶性维生素、甾醇等脂溶性成分及其功效的研究进展,以及磷虾油提取方法、多种成分稳定性的研究结果,并展望了我国开展南极磷虾脂溶性成分综合利用的前景。     

猴头菌小分子活性成分研究进展

综述猴头菌(Hericium erinaceus)小分子活性成分的研究进展,旨在为这类物质的进一步开发利用提供参考。