Sulfoquinovosyldiacylglycerins from Scaphechinus mirabilis

Development of a targeted HPLC-ESI-QqQ-MS/MS method for the quantification of sulfolipids from a cyanobacterium, selected leafy vegetables, and a microalgae species

The use of macro- and microalgae, as well as cyanobacteria, becomes increasingly important for human nutrition, even in Western diets. Health effects, positive as well as negative, are believed to result mainly from minor components in the food. In macro- and microalgae as well as in certain cyanobacteria, one class of such minor compounds is sulfolipids, more precisely sulfoquinovosylmonoacylglycerol (SQMG) and sulfoquinovosyldiacylglycerol (SQDG) derivatives. SQMGs and SQDGs consist of a diacylglycerol esterified with varying fatty acid combinations and a sulfoquinovose moiety. Sulfoquinovose is a sulfonated hexose analogous to D-glucose, but featuring a stable carbon-sulfur bond. With regard to their chemical structure, SQDGs can be distinguished according to their sn1- and sn2-bound fatty acids. Although there is great interest in SQDGs, because of their controversially discussed bioactivities, only a negligible number of comprehensive methods for identification and quantification has been published, so far. Within this work, a sample preparation including a quantitative isolation of SQDGs from selected raw materials, a clean-up with solid-phase extraction (SPE), and a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous identification and quantitation of different, intact SQMGs and SQDGs were developed and validated. The applicability of the method was further demonstrated by comparing a prominent cyanobacterium (Arthrospira sp.) with a microalgae preparation (Chlorella vulgaris), and selected leafy vegetables (spinach, basil).

Lipid Isolation Process and Study on Some Molecular Species of Polar Lipid Isolated from Seed of Madhuca ellitica

This study attempted the lipid extraction process from the seeds of Madhuca ellitica, a lipid-rich plant, and conducted a lipidomic analysis on molecular species of the obtained product. Total lipids of the crude seeds were found to contain 11.2% of polar lipids. The major fatty acids (FAs) of the polar lipids were palmitic (16:0), stearic (18:0), oleic (18:1n-9), and linoleic (18:2n-6) acids, which amounted to 28.5, 12.5, 44.8, and 13.2% of total FAs, respectively. The content and chemical structures of individual molecular species of phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidic acid (PA), and sulfoquinovosyldiacylglycerol (SQDG) were determined by HPLC with a tandem high-resolution mass spectrometry (HRMS). The major molecular species were 18:1/18:2 PE, 16:0/18:1 PC, 18:1/18:2 PC, 16:0/18:2 PG, 16:0/18:1 PG, 16:1/18:1 PI, 16:0/18:1 PI, 18:0/18:2 PI, 16:0/18:1 PA, 18:1/18:2 PA, 16:0/18:1 SQDG, and 18:0/18:1 SQDG. The application of a tandem HRMS allows us to determine the content of each isomer in pairs of the monoisotopic molecular species, for example, 18:0/18:2 and 18:1/18:1. The evaluation of the seed polar lipid profile will be helpful for developing the potential of this tree for nutritive and industrial uses.

Examination of the structures of several glycerolipids from marine macroalgae by NMR and GC-MS

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.

Antiviral Sulfoquinovosyldiacylglycerols (SQDGs) from the Brazilian brown seaweed Sargassum vulgare

Total lipids from the Brazilian brown seaweed Sargassum vulgare were extracted with chloroform/methanol 2:1 and 1:2 (v/v) at room temperature. After performing Folch partition of the crude lipid extract, the lipids recovered from the Folch lower layer were fractionated on a silica gel column eluted with chloroform, acetone and methanol. The fraction eluted with methanol, presented a strong orcinol-positive band characteristic of the presence of sulfatides when examined by TLC. This fraction was then purified by two successive silica gel column chromatography giving rise to fractions F4I86 and F4II90 that exhibited strong activity against herpes simplex virus type 1 and 2. The chemical structures present in both fractions were elucidated by ESI-MS and ¹H/¹³C NMR analysis HSQC fingerprints based on their tandem-MS behavior as Sulfoquinovosyldiacylglycerols (SQDGs). The main SQDG present in both fractions and responsible for the anti-herpes activity observed was identified as 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)-glycerol.