COMPARATIT7E STEROLS COMPOSITIOX OF THE RED ALGA ASPARAGOPSIS ARiWA T A AND ITS TETRASPOROPHYTE FA L K E AT13 ERGIA R U FOL A SOSA GEORGESCOMBACT, TTESBRCNEAC, LOCISCODOMIER ET JEAX TESTE Groiipe de reciierches en biologie et chiniie vkgktules marines Cenire L?iivcrsifuire, Perpignun, France
AiBSTRICT.-The sterol content ranged from 0.0155 of the dry weight for Asperegopszs arniafa t o O.Oi5% for Fulkenbergza rzifolanosa. Four samples at different reproductive states are analyzed by means of gas-liquid chromatography and gas-liquid chromatography-mas? spectrometry. Cholesterol 2 is aln-ays the major sterol. In ever?- case tn-o cholesta-diene-diols 8a, 8b and tn-o cholestene-diols 3, 6 have been identified.
The red alga Asparagopsis armaia Harv. i. a dioecious gametophytic plant that alternates in its life cycle n-ith a heteromorphic tetrasporophyte knovn as Falkeizbergia rufolenosa (Harv.) Schniitz. The comparative chemical composition of the gametophyte and the tetrasporophj-te has been previously reported for halogenated compounds (1). R e have non- studied the sterol content of some samples of Asparagopsis arinata and Falkenbergia rz~folaiiosaat different reproductive states (table 1). TIBLE 1. Santples stzidiedfor sterols. I
Samples
-11
F1 F2 l2
Date
'
I
3rd Mar 1976 29th Jun 1976 14th Jan 1976 20th Dec 1970
1
Reproductive state A s p a r a g o p s i s urnia!a young without fructification A s p a r a g o p s i s arniefa with fructifications Fulkenbergie rz4folunosa young n-ithout tetraspore Falkenbergia rufolenosa p-ith tetraspores
IIATERIALS AKD METHODS Male and female plants of Asparagopsis arnzate, which were not separated for this investigation, and the asexual Falkenbergza rujolanosa were obtained along the Catalan Mediterranean coast near Banyuls-sur-Mer in France. The freshly collected, wet plants were extracted with methanol, chloroform, and ethanol. Solvents were evaporated, and the residues were transferred into ethyl ether t o give the lipid oil, which was saponified. Sterols were precipitated from the non-mponifiable fraction with digitonin (2). Further purification was obtained by tlc with pentane-ethyl acetate (7:3v/v) as eluant. I n the same manner as previously described, sterols were identified as their trimethylsilpl ethers by means of gas chromatography-mass spectrometry (gc-ms) technique (3). Sterol analyses --ere made on free sterols; a 5% OTr-l column a t 280°C w-as used for quantitative determination (4).
RESULTS A S D DISCUSSIOK The tetrasporophyte contains significantly greater concentrations of total sterols than the gametophyte. Their amounts increase during fructification of the gametophyte and slo~vlydecrease during appearance of tetraspores for the sporophytic plant (fig. 1). Table 1 shom the estimation of each sterol.1 Cholesterol 2 is the major sterol in all samples analyzed; desmosterol 3 is abundant only for the gametophyte and 'For the identification of these sterols by gc-ms, see previous report (4) 150
COMBAUT E T IL.:
19i9]
11.4R-APR
Sterols
X
151
STEROLS
*T I
**
3 1
Reproductive state
r) I
FIGURE 1 . d n i o i o i t of sterols oj' Aspsragopsis armata atid Falkenbergia rufolanosa *Based on dry Teight of algae. **1sterile plant 2 frunctificated plant.
P2-deli\-dro-choleaterol 1 for t h e sterile -4sparagopsis a r m a f a . The three cliol- 3, 6, 8 are present in both gametophytic and sporphytic plants. T IBLE 2
Estzviatzo,i
Sterols** identified as
~
of sterols.
5 of total sterols analyzed
.-.snples I
2 _ _ _ _ _ _ _ ~ 1
3
4
5
6
1
-
8
~___________________~_
**1, 22-dehgdro-cholesterol: 2. cholesterol: 3, desmosterol; 4, brassicasterol: 3, -?j-h~droz~--cholesterol: 6? 2.5-h~-drosy-2-l-nieth~lcholesterol: 7 , fncosteroltp sitosterol: 8a, liagosterol and 8b, choles:a-5,25-dien-3.?> "-diol (1).
.ICKSOWLEDGhIEXTS The hiithum thank 11.Prost for his aid in gc-ms technique. This work was supported h>-a grant from the .'Centre S a t i o n a l de la T?echerche.$cientifique" (Programmed Thematic .\?tion: Chemical Oceancigraphy) . R e c e i w d 6 Fehrictrr): 1978. 1,ITERATLRE CITED 1.
T.BRCSE.\L-, L. CODOJIIER,G . COMBACT and J. TESTE,C. R.Actid. Sc. PrTris, 284D. 1163
(1977). J . TESTE and L. CODOMIER, Phxcoiogia, 2 . C;. COMB.\CT,1.BRL-sE.\L-,G . JE.\srT, c . FR.ISCISCO, 1.5, 27.5 (19i6). C;. COJIB.\UT! J . TESTE and B. F. 1 f . i L X E , B i o c h e ~ .Biopt'iTs. - $ c t c ~487, ~ 115 3 . C . FR.ISCISCO, il9TT). J . TESTE,L. CODOMIER and 11. PROST; TO be 4 . C;. CCi\lB.lL-T. 1.BRUSE.LL-,C . FR.ISCISCO, piihlisbed.
