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Several classes of glycerolipids were isolated from the total lipids of the algae Saccharina cichorioides, Eualaria fistulosa, Fucus evanescens, Sargassum pallidum, Silvetia babingtonii (Ochrophyta, Phaeophyceae), Tichocarpus crinitus, and Neorhodomela larix (Rhodophyta, Florideophyceae). The structures of these lipids were examined by nuclear magnetic resonance (NMR) spectroscopy, including 1D ((1) H and (13) C) and 2D (COSY, HSQC and HMBC) experiments. All of the investigated algae included common galactolipids and sulfonoglycolipids as the major glycolipids. Minor glycolipids isolated from S. cichorioides, T. crinitus, and N. laris were identified as lyso-galactolipids with a polar group consisted of the galactose. Comparison of the (1) H NMR data of minor nonpolar lipids isolated from the extracts of the brown algae S. pallidum and F. evanescens with the (1) H NMR data of other lipids allowed them to be identified as diacylglycerols. The structures of betaine lipids isolated from brown algae were confirmed by NMR for the first time. The fatty acid compositions of the isolated lipids were determined by gas chromatography-mass spectrometry.

The present study describes the content of total lipids (TL), the main components of polar and neutral lipids (NL) and photosynthetic pigments (PSP) in edible seaweed Sargassum pallidum (Ochrophyta) from the Sea of Japan, Russia, in different months of the year, taking into account life cycle. Special attention was paid to the fatty acids (FAs) of total lipids as well as the accumulation of important polyunsaturated fatty acids (PUFAs) in glyceroglycolipids (GL) and reserve lipids in the seasonal cycles of growth. The content of TL strongly varied in the course of a year. The major lipid components were GL (20.3% -36.4%) and NL (19.8% -30.6%), while phospholipids (PL) were present in negligible amounts (3.2% -6.9%). Significant seasonal variations were observed in content all classes of lipids. The PUFAs prevailed in total lipids and the content of n-6 PUFAs was higher than n-3 PUFAs on all stages of life with the exception of vegetation period. Monogalactosyldiacylglycerols (MGDG) and digalactosyldiacylglecerols (DGDG) were rich in PUFAs and n-3 PUFAs were dominated among them independently of stages of growth. Saturated fatty acids (SFA) were dominated in sulfoquinovosyldiacylglycerols (SQDG). Triacylglycerols (TAG) and diacylglycerols (DAG) contained many PUFAs, especially n-6 PUFAs. Significant concentration 20:3 n-6 was in the triacylglycerols. The concentration of chlorophylls and carotenoids was increased with the growth and maturation of S. pallidum and reached maximum in period of highest day length and water temperature. The content of pigments decreased with the onset of short days and decreasing water temperatures. Nutritional value and benefit for health of human this alga were evaluated. The n-6/n-3 PUFAs ratio, nutritional quality index (atherogenic and thrombogenic indices, and ratio between hypocholesterolemic and hypercholesterolemic fatty acids) were low, suggesting a high nutritional value of S. pallidum throughout the year.

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