Phospholipids of New Zealand Edible Brown Algae

Abstract

Edible brown algae have attracted interest as a source of beneficial allenic carotenoid fucoxanthin, and glyco- and phospholipids enriched in polyunsaturated fatty acids. Unlike green algae, brown algae contain no or little phosphatidylserine, possessing an unusual aminophospholipid, phosphatidyl-O-[N-(2-hydroxyethyl) glycine], PHEG, instead. When our routinely used technique of P-NMR analysis of phospholipids was applied to the samples of edible New Zealand brown algae, a number of signals corresponding to unidentified phosphorus-containing compounds were observed in total lipids. NI (negative ion) ESI QToF MS spectra confirmed the presence of more familiar phospholipids, and also suggested the presence of PHEG or its isomers. The structure of PHEG was confirmed by comparison with a synthetic standard. An unusual MS fragmentation pattern that was also observed prompted us to synthesise a number of possible candidates, and was found to follow that of phosphatidylhydroxyethyl methylcarbamate, likely an extraction artefact. An unexpected outcome was the finding of ceramidephosphoinositol that has not been reported previously as occurring in brown algae. An uncommon arsenic-containing phospholipid has also been observed and quantified, and its TLC behaviour studied, along with that of the newly synthesised lipids.

Polar lipid profile of Saccharina latissima, a functional food from the sea

“…Arsenolipids were identified for the first time in the brown alga Undaria pinnatifida (wakame) [40]. This class of lipids occurs naturally in marine foods, such as fish and macroalgae [41][42][43]. Their presence in S. latissima was already reported by Raab et al.…”

The lipid biochemistry of eukaryotic algae

“…All the usual phosphoglycerides are found even in minor amounts but phosphatidylcholine (PtdCho), phosphatidylethanolamine (PtdEtn) and phosphatidylglycerol (PtdGro) are the main ones. Even in brown algae there is a wide variation in the percentages of different phosphoglycerides [28]. Phosphatidyl-O-N- (2-hydroxyethyl)glycine (PHEG: preciously called N-CAPE), a ceramidephosphoinositol and an arsenic-containing phospholipid were also detected in a variety of brown algal species [28].…”

Lipidomics of the Edible Brown Alga Wakame (Undaria pinnatifida) by Liquid Chromatography Coupled to Electrospray Ionization and Tandem Mass Spectrometry

“…Concerning lipid fraction, several studies on brown algae have been focused on minor arsenosugar phospholipids [ 16 , 17 , 18 ], arsenic-including hydrocarbons [ 19 , 20 ], and free polyunsaturated fatty acids [ 21 , 22 ]. While the knowledge of glycolipids (GL) and PL is foremost in red algae [ 23 ], these compounds have been only partially investigated in brown algae [ 24 ]. There has been extensive research regarding the fatty-acidome of algae; for instance, Řezanka et al [ 25 ] focused on the characterization of total long-chain fatty acids in green algae Botryococcus by GC-MS.…”