Marine lipids
The fatty acid esters were analysed by gas chromatography on a capillary gas column SGE BPX 70 (50 m long, 0.22 mm diameter, 0.25 pm
stickness stationary phase). The chromatograph used was an apparatus
Autosystem Perkin-Elmer, coupled to an integrator Turbochrom Perkin-Elmer. The carrier gas was helium at pressure 0.6 bar and the temperature gradient was programmed from 35°C (for 7 min) to 150°C
at 20°C per minute and then to 2 30°C at 1.5°C per minute. Fatty acid
esters were identified by their retention times.
Results and discussion
The phospholipids represented 97.7% (w/w) of fish oil’s total lipids by
quantification on silica gel. Separation of the various classes of phospholipids was achieved by HPLC and showed that PC was primarily
represented witli 48.3% (w/w) of total phospholipids (Baudimant et al.,
1996). The fatty acid profile obtained for phosphatidylcholine showed
that DHA was 39.7% of total fatty acids (table 1) ).
Table 1 - Fatty acid composition of phospholipids and PC expressed
in percentage of fatty acids.
Fatty acids
Total Phospholipids
PC
Toc. Sat.
35.5
44. 3
Tot. Mon.
8.2
7.5
20:4 ω6
4.3
1.0
20:5 ω3
16.7
5 0
22:6 ω3
33.1
39.7
Tot. Sat.: Total saturated fatty acids;
Tot. Mon.: Total monounsaturated fatty acids.
Phosphatidylcholine was purified by CPC from the crude extract in the
system heptane-ethyl acetate-acetonitrile. Experiment was carried out
dissolving 0.25 g of total phosphatides in 5 ml of mobile phase and
injecting into the analytic column. The upper phase (less polar phase)
was used as mobile phase. The less polar phospholipids were eluted
first, whereas the most polar remained in the column.
The first three fractions contained phospholipids PE, PI, PS, SM and
traces of PC. One contaminant compound was the collected in the next
fractions 5 to 1 2 and analysis showed it was a mixture containing 89%
cholesterol, 5% cholesterol esters and little amount of PC. After running
one volume of mobile phase through the column in the normal ascending
mode, phosphatidylcholine was eluted in the stationary phase (lower
phase). PC was obtained pure with an estimated yielcl of 95% of total
injected PC.
After analysis, the fractions of PC showed high content of palmitic acid
and docosahexaenoic acid. Several molecular species were identified
after hydrolysis with phospholipase A2. The major molecular species
was apparently pure (16:0/22: 6 ω3).
18
The fatty acid esters were analysed by gas chromatography on a capillary gas column SGE BPX 70 (50 m long, 0.22 mm diameter, 0.25 pm
stickness stationary phase). The chromatograph used was an apparatus
Autosystem Perkin-Elmer, coupled to an integrator Turbochrom Perkin-Elmer. The carrier gas was helium at pressure 0.6 bar and the temperature gradient was programmed from 35°C (for 7 min) to 150°C
at 20°C per minute and then to 2 30°C at 1.5°C per minute. Fatty acid
esters were identified by their retention times.
Results and discussion
The phospholipids represented 97.7% (w/w) of fish oil’s total lipids by
quantification on silica gel. Separation of the various classes of phospholipids was achieved by HPLC and showed that PC was primarily
represented witli 48.3% (w/w) of total phospholipids (Baudimant et al.,
1996). The fatty acid profile obtained for phosphatidylcholine showed
that DHA was 39.7% of total fatty acids (table 1) ).
Table 1 - Fatty acid composition of phospholipids and PC expressed
in percentage of fatty acids.
Fatty acids
Total Phospholipids
PC
Toc. Sat.
35.5
44. 3
Tot. Mon.
8.2
7.5
20:4 ω6
4.3
1.0
20:5 ω3
16.7
5 0
22:6 ω3
33.1
39.7
Tot. Sat.: Total saturated fatty acids;
Tot. Mon.: Total monounsaturated fatty acids.
Phosphatidylcholine was purified by CPC from the crude extract in the
system heptane-ethyl acetate-acetonitrile. Experiment was carried out
dissolving 0.25 g of total phosphatides in 5 ml of mobile phase and
injecting into the analytic column. The upper phase (less polar phase)
was used as mobile phase. The less polar phospholipids were eluted
first, whereas the most polar remained in the column.
The first three fractions contained phospholipids PE, PI, PS, SM and
traces of PC. One contaminant compound was the collected in the next
fractions 5 to 1 2 and analysis showed it was a mixture containing 89%
cholesterol, 5% cholesterol esters and little amount of PC. After running
one volume of mobile phase through the column in the normal ascending
mode, phosphatidylcholine was eluted in the stationary phase (lower
phase). PC was obtained pure with an estimated yielcl of 95% of total
injected PC.
After analysis, the fractions of PC showed high content of palmitic acid
and docosahexaenoic acid. Several molecular species were identified
after hydrolysis with phospholipase A2. The major molecular species
was apparently pure (16:0/22: 6 ω3).
18