Biomarkers
of the gorgonian Leptogorgia piccola (white and yellow morphs) has
been recently described (Mirallès et al., 1995). It has also shown that,
unlike other marine organisms, the gorgonians can extend their polyunsaturated fatty acid biosynthetic sequences to the longer chain
methylene-interrupted tetracosapolyenoic fatty acid, especially in the
(n-3) and (n-6) series (Carballeira et al., 1996a, 1997a, b).
We investigated gorgonians as a part of our ongoing research on lipids
from Cnidaria. In conjunction with our research on biologically active
compounds from the New Caledonian gorgonian Rumphella aggregata
(Plexauridae) (Urvois, 1998), and in consideration of the high level of
lipids and fatty acids usually occurring in this order, we investigated
lipid distribution and fatty acid composition of several fractions of
total lipids of this R. aggregata. This is what this report describes. Fatty
acid composition and structure elucidation were determined by GC/MS.
Several interesting unsaturated fatty acids were identified, including
a new one, namely 9-methyl-6,9-17:2.
Experimental procedures
Gorgonian material and lipid extraction
Specimens of R. aggregata were collected by scuba diving in April 1996
at "Lejardin d'Ua” (22°43'00 S, 166°49'10 E), New Caledonia. The
gorgonian was washed in sea water, ground in a blender and then
lyophilized.
Total lipids of the gorgonian sample were steeped three times in chloroform-methanol (1:1, v/v) for 24 h at room temperature.
Combined crude total lipids were chromatographed on an open silica
column (40-60 mesh) using solvents of increasing polarity in order to
separate the different classes: hexane, chloroform (neutral lipids), acetone (glycolipids) and methanol (phospholipids). Fatty acids were
characterized as methyl esters and pyrrolidide derivatives by GC/MS.
The fatty acyl components of these lipid fractions were obtained as
their methyl esters by refluxing with 2% methanolic hydrogen chloride (40 min).
To determine clouble bonds and methyl branching, methyl esters were
converted into their N-acyl pyrrolidides by treatment with pyrrolidine-acetic acid (10:1, v/v) under reflux (2 h). Pyrrolidides were purified
by TLC on an 0.5 mm silica gel layer using hexane-diethyl ether (1:2,
v/v) as developing solvent.
GC/MS
Combined GC/MS was performed on a HP-5890 chromatograph linked
to a HP-9000/345 integrator.
The GC column was a 30 m x 0.32 mm i.d. fused silica capillary column
coated with DB-1 (0.25 mm phase thickness). The carrier gas was
helium. Pyrrolidide derivatives were analysed from 180°C to 300°C at
3°C per minute.
45
of the gorgonian Leptogorgia piccola (white and yellow morphs) has
been recently described (Mirallès et al., 1995). It has also shown that,
unlike other marine organisms, the gorgonians can extend their polyunsaturated fatty acid biosynthetic sequences to the longer chain
methylene-interrupted tetracosapolyenoic fatty acid, especially in the
(n-3) and (n-6) series (Carballeira et al., 1996a, 1997a, b).
We investigated gorgonians as a part of our ongoing research on lipids
from Cnidaria. In conjunction with our research on biologically active
compounds from the New Caledonian gorgonian Rumphella aggregata
(Plexauridae) (Urvois, 1998), and in consideration of the high level of
lipids and fatty acids usually occurring in this order, we investigated
lipid distribution and fatty acid composition of several fractions of
total lipids of this R. aggregata. This is what this report describes. Fatty
acid composition and structure elucidation were determined by GC/MS.
Several interesting unsaturated fatty acids were identified, including
a new one, namely 9-methyl-6,9-17:2.
Experimental procedures
Gorgonian material and lipid extraction
Specimens of R. aggregata were collected by scuba diving in April 1996
at "Lejardin d'Ua” (22°43'00 S, 166°49'10 E), New Caledonia. The
gorgonian was washed in sea water, ground in a blender and then
lyophilized.
Total lipids of the gorgonian sample were steeped three times in chloroform-methanol (1:1, v/v) for 24 h at room temperature.
Combined crude total lipids were chromatographed on an open silica
column (40-60 mesh) using solvents of increasing polarity in order to
separate the different classes: hexane, chloroform (neutral lipids), acetone (glycolipids) and methanol (phospholipids). Fatty acids were
characterized as methyl esters and pyrrolidide derivatives by GC/MS.
The fatty acyl components of these lipid fractions were obtained as
their methyl esters by refluxing with 2% methanolic hydrogen chloride (40 min).
To determine clouble bonds and methyl branching, methyl esters were
converted into their N-acyl pyrrolidides by treatment with pyrrolidine-acetic acid (10:1, v/v) under reflux (2 h). Pyrrolidides were purified
by TLC on an 0.5 mm silica gel layer using hexane-diethyl ether (1:2,
v/v) as developing solvent.
GC/MS
Combined GC/MS was performed on a HP-5890 chromatograph linked
to a HP-9000/345 integrator.
The GC column was a 30 m x 0.32 mm i.d. fused silica capillary column
coated with DB-1 (0.25 mm phase thickness). The carrier gas was
helium. Pyrrolidide derivatives were analysed from 180°C to 300°C at
3°C per minute.
45