56
and EPA as major FAs (Hofmann and Eichenberger 1997; Makewicz et al. 1997).
Monoacylglyceryl-N,N,N-trimethylhomoserine (MGTS) molecular species have
also been reported recently in one of the green seaweed of taxa Codium tomentosum
Stackhouse (da Costa et al. 2015). Betaine lipids constitute minor fractions or have
been unidentified in most of the red seaweeds except for DGTS (Künzler and
Eichenberger 1997) until recently when Melo et al. (2015) identified 36 DGTS
molecular species using advanced lipidomic approaches in Chondrus crispus
Stackhouse, containing DGTS 16:0/16:1 as the most abundant DGTS molecular
species followed by 16:0/16:0 and 14:0/18:0. This study shows the unparalleled
strength of advanced lipidomic approaches that may lead to re-characterization of
seaweed lipid profiles in the near future. DGTA is considered to play an important
role in the redistribution of acyl chains and the biosynthesis of saccharolipids and
DGTS in lipid-linked desaturation of fatty acids (Hofmann and Eichenberger 1998).
4.2.5 Sphingolipids
Sphingolipids in seaweeds are mainly present in red seaweeds in small amounts.
These include cerebrosides and ceramides and inositolphosphoceramide (IPC)
(Bano et al. 1990; Khotimchenko et al. 2000; Khotimchenko and Vaśkovsky 2004;
Lo et al. 2001; Vaśkovsky et al. 1996). Only IPC was fully characterized from
Gracilaria verrucosa (Hudson) Papenfuss (Khotimchenko et al. 2000; Khotimchenko
and Vaśkovsky 2004) that contained palmitic (51.7%), stearic (23.2%), myristic
(9.8%), oleic (9.8%), and palmitoleic acids. Recently, Melo et al. (2015) characterized 15 molecular species of IPC from C. crispus containing C18:0/C26:0 as the
most abundant molecular species.
4.2.6 Fatty Acyls
Fatty acyls include fatty acids, their conjugates, and their oxidized products
(oxylipins).
4.2.6.1 Fatty Acids
Fatty acids (FAs) are carboxylic acids with long aliphatic chains that may be straight
or branched, saturated or unsaturated. Seaweeds mostly contain even carbon fatty
acids (C4-C28); however, odd-chain FAs are also present in minor amounts. FAs are
classified as monounsaturated FAs (MUFAs, with 1 double bond) and polyunsaturated FAs (PUFAs, with ≥2 double bonds) on the basis of the number of double
bonds present. Further, PUFAs are classified as n-3 or n-6 FAs depending on the
P. Kumari
and EPA as major FAs (Hofmann and Eichenberger 1997; Makewicz et al. 1997).
Monoacylglyceryl-N,N,N-trimethylhomoserine (MGTS) molecular species have
also been reported recently in one of the green seaweed of taxa Codium tomentosum
Stackhouse (da Costa et al. 2015). Betaine lipids constitute minor fractions or have
been unidentified in most of the red seaweeds except for DGTS (Künzler and
Eichenberger 1997) until recently when Melo et al. (2015) identified 36 DGTS
molecular species using advanced lipidomic approaches in Chondrus crispus
Stackhouse, containing DGTS 16:0/16:1 as the most abundant DGTS molecular
species followed by 16:0/16:0 and 14:0/18:0. This study shows the unparalleled
strength of advanced lipidomic approaches that may lead to re-characterization of
seaweed lipid profiles in the near future. DGTA is considered to play an important
role in the redistribution of acyl chains and the biosynthesis of saccharolipids and
DGTS in lipid-linked desaturation of fatty acids (Hofmann and Eichenberger 1998).
4.2.5 Sphingolipids
Sphingolipids in seaweeds are mainly present in red seaweeds in small amounts.
These include cerebrosides and ceramides and inositolphosphoceramide (IPC)
(Bano et al. 1990; Khotimchenko et al. 2000; Khotimchenko and Vaśkovsky 2004;
Lo et al. 2001; Vaśkovsky et al. 1996). Only IPC was fully characterized from
Gracilaria verrucosa (Hudson) Papenfuss (Khotimchenko et al. 2000; Khotimchenko
and Vaśkovsky 2004) that contained palmitic (51.7%), stearic (23.2%), myristic
(9.8%), oleic (9.8%), and palmitoleic acids. Recently, Melo et al. (2015) characterized 15 molecular species of IPC from C. crispus containing C18:0/C26:0 as the
most abundant molecular species.
4.2.6 Fatty Acyls
Fatty acyls include fatty acids, their conjugates, and their oxidized products
(oxylipins).
4.2.6.1 Fatty Acids
Fatty acids (FAs) are carboxylic acids with long aliphatic chains that may be straight
or branched, saturated or unsaturated. Seaweeds mostly contain even carbon fatty
acids (C4-C28); however, odd-chain FAs are also present in minor amounts. FAs are
classified as monounsaturated FAs (MUFAs, with 1 double bond) and polyunsaturated FAs (PUFAs, with ≥2 double bonds) on the basis of the number of double
bonds present. Further, PUFAs are classified as n-3 or n-6 FAs depending on the
P. Kumari