Carotenoids from three red algae of the Corallinaceae

Phyrochemisrry,

Vol. 30, No. 9. pp. 2983 2986, 1991

003I-9422p153.00 + 0.00 PergamonPressplc

Printedin Great Britain.

CAROTENOIDS

FROM THREE

RED ALGAE OF THE CORALLINACEAE

JORGE A. PALERMO, EDUARW

G. GROS

and ALICIA M. SELDES

Departamento de Quimica Organica, Fact&ad de Ciencias Exactas y Naturales, Universidad de Buenos Aires Pab. 2 - C. Universitaria, 1428 Buenos Aires, Argentina (Received in revised form 9 January 1991)

Key Word LDdex-Coralh oficinalis; Corallina elongata; Jania sp.; Rhodophyceae; fucoxanthin; fucoxanthinol; mutatoxanthin.

Corallinaceae;

carotenoids;

Abstract-The carotenoid composition of the red algae Corallina ojicinalis, Corallina elongata and Jania sp. were analysed. The same eight compounds were isolated and identified from the three species: p-carotene, zeaxanthin, fucoxanthin, 9’-cis-fucoxanthin, fucoxanthinol, 9’-cis-fucoxanthinol and the epimeric mutatoxanthins. The latter two components are described for the first time as natural products from the marine environment. The results allowed us to infer that Corallinaceae are able to produce de nouo allenic and epoxy carotenoids, contrary to the general supposition that their presence in the algae was due to colonizing organisms.

The carotenoid composition of red algae has been described as relatively simple and consisting mainly of bicyclic carotenes with j?,jl and ~I.Eend groups and their 3,3’-dihydroxylated derivatives [l-3]. Carotenoids with allenic and epoxy-end groups were supposed to have an exogenous origin [4]. Continuing with our interest on the natural products isolated from marine organisms [S] we report here the isolation and characterization of the carotenoids of three species of algae of the family Corallinaceae (order Cryptonemiales), namely Coraha oficinalis (Link), Corallina elongata (Areschoug) and Jania sp. Two of the carotenoids, (8R)- and (8S)-mutatoxanthin were detected for the first time as natural products in the marine environment.

b

d

R=H

e

R=Ac

RESULTS

The carotenoid composition of each of the algae is shown in Table 1. The three species showed almost the same carotenoid profile. /I&Carotene* (1) was, as expected the most abundant component in the three species while zeaxanthin (2) was isolated only in small amounts. Both of these were the only typical red algae carotenoids. Compound 3 was identified as fucoxanthin by comparison of the IR, ‘H, 13C NMR and mass spectra with published data [6-81. The 13C NMR signals corresponding to the end groups of fucoxanthin and also those of compounds 1, 2, 5-7 were in accordance with values published by Englert [7,8] assignment of these spectra.

and

allowed

30:9-L

5 g-P-b

3 C-P-e

6 CP-b 7 c-P’-d

4 c-P”-c

II c-P’-d

Fig. I. Carotenoids

of the red algae Corallima osfciaulis, C. elongata and Maniasp.

a complete

*Systematic names of the carotenoids. p-carotene = /I. Bcarotene, zeaxanthin = j?$-carotene-3,3’-dial; fucoxanthin = 5,6epoxy-3.3’,S-trihydroxy-6’,7’didehydro-S,6,7,8,~,~-hexahydr~ /I,/?-caroten-8-one-3’-acetate; fucoxanthinol= 5,6-epoxy-3,3’,5’trihydroxy-6’,7’didehydro-5,6,7,8,5’,6’-hexahydro-B,B-carotenmutatoxanthin = 5,8-epoxy-5,8-dihydro-/I./?-caroteneg-one; 3’ 01. PityTo

1 r-P-0 2 b-P-b

Compound 4 showed IR and mass spectra almost identical to those of 3, suggesting that it is an isomer of fucoxanthin. The ‘H NMR spectrum was also closely similar to that of 3 except for the signal at 66.06 corresponding to H-8’ shifted to 66.55 and minor differences in the chemical shifts of C- 16’and C- 17’ methyl groups. This compound. first characterized by Weedon [9] as the allenic 6’Sepimer of fucoxanthin was recently identified

J. A. PALFXMO

2984

by Liaaen-Jensen [lo] as 9’-cis-fucoxanthin (4), probably an artifact due to a photochemical rearrangement. Compounds 5 and 6 are isomers, as shown by their identical mass spectra. Their ‘H NMR spectra were closely similar in the region of 66 7, with slight differences in some methyl groups shifts. The pair of signals in the region of d5- 5.3 (5: br s at 65.18 and 5.26; 6: doublets at 85.08 and 5.33) were characteristic of 5&epoxy end groups of a pair of C-8 epimers [I 1. 131. The remaining signals corresponded to a 3’/1-hydroxy end-group. The presence of a 3-hydroxy-5,8-epoxy end-group could also be inferred by the presence of the characteristic fragments m/z 504, 221 and 181 in their mass spectra [ 143. Compounds 5 and 6 are (8R)- and (XS)-mutatoxanthin, respectively [IS]. Compound 7 showed ‘H NMR spectra very similar to that of 3. The absence of signals corresponding to a 3’acetyl group and comparison with published data [7,8] allowed its identification as fucoxanthinol. The mass spectrum of 8 was identical to that of 7 and the ‘H NMR spectrum resembled that of 7 in the same way as 3 and 4. By analogy to 4. compound 8 was identified as 9’-cis-fucoxanthinol.

Compounds 5 and 6 are common constituents of higher plants [l5] and are claimed to be the dominant carotenoids in lichens of the genus Xanthoria, although their identification is tentative [ 181. In the marine environment, they have been detected as post mortem artifacts in the red alga Eryfhrorrichia curneu, presumably due to furanoid rearrangement of antheraxanthin during storage of the frozen material. These compounds were not detected in the freshly extracted material [ 193. In our case extractions were performed on the fresh material on the same day of collection and at room temperature. Besides that. antheraxanthin, the’precursor’ofthese compounds, was not detected in any collection. Although some degree of epimerization could have taken place during chromatography, these facts suggest that this algae can produce cpoxycarotenoids, being the first occasion that these compounds are detected as natural products of freshly collected marine organisms. According to our results, the Corallinaceae contain significant amounts of allenic carotenoids and are able to produce epoxy carotenoids, but not c end-groups.

EXPERIMENTAL Gc~rul.

DISCUSSION

C-18

The presence of fucoxanthin in red algae has been reported on several occasions [16, 171 and in many cases was attributed to the presence of biological contaminants, mainly diatoms and Chrysophyceae. In some cases, comparison of natural samples with cultured material showed that this carotenoid was not produced by the algae themselves [4]. In the present case, microscopic examination of samples of the different collections did not reveal the presence of diatoms or other contaminants to such an extent as to account for the relatively large yields of fucoxanthin and fucoxanthinol in the three species. Taking into account that the dry weight of these algae consists mainly of CaCO,, the yield of these compounds per dry weight of organic tissue is considerably larger than the amounts stated in Table I. However, the real origin of compounds 3, 4, 7 and 8 remains uncertain, because their production by a microscopic symbiotic organism cannot be ruled out. Compounds 7 and 8 were detected, to the best of our knowledge, for the first time in the class Rhodophyceae.

Table

1. Carotenoidal

composition

Mgw

HPLC

lO/lrn

pound

2: MeOH

(19: I);

IOmm) H,O

compounds

100.1 MHz. P/am

“C

and Altex

8:

compounds

ODS

5/lrn

I: Me,CO;

com-

3+

H,O

MeOH-H,O

(9:l).

c!fficinu/is

(Link)

and

and

collecicd in the intertidal zone at wcrc

done in 1h.c summer months. Ertracrion with

und isqhrron.

EIOH

tracted

Immediately

and was further

were coned

at

red. pres. and the remaining aq. phase partitioned

10 afford

and H,O.

The organic phase was cvapd a1 red.

a gr‘yn syrup (33.4 g for C. r~ffrcinulis. 26.3 g for C.

elonqaru and 23.2 g for Mania sp.) which was fractioned column flash chromatography of hexane- EtOAc Nere employed

of Coralha

oficinalis. c.

lmg

on silica gel

and ElOAc-MeOH

(I 50 g).

of increasmg

polarity

C. donyatc~ and Janfa sp. Jania sp. IOOg

.-.

Mgper

%

dry WI

%

dry wt

60.8

18.4

74.8

12.2

53.3

20.9

5.0

1.5

3.4

0.6

2.3

0.9

14.4

4.4

12.2

2.0

21.3

Ir.

tr.

tr.

tr.

lr.

x.4

tr

5.5

I.7

I .4

0.2

7.1

2.7

5.5

1.7

1.4

0.2

7.1

2.7

8.8

2.7

6.8

1.1

8.9

3.5

tr.

tr.

tr.

tr.

lr.

tr.

which consisted mostly of CaCO,.

by dry

Fifteen mix&

for the clution of the different frs. The frs were

&~ngula Mgper

*Based on yields of isolated individual compounds.

ex-

x 3 with CH,C‘12 at room temp. The combined cxtrac1s

between EtOAc pres.

The fresh material was homogenized after collectIon

dry wtt

material

zone at 9.2 kg we1

(8.6 kg wet wt). All collections

%*

t Lipid extracted

Corullino

In the intertidal

Argentina (9 8 kg we1 wt of C. @irkdi.s

del Plata. Argentina

‘H NMR:

MS were performed at 7OcV.

were collected

WIof C. c+~~yura).Janice sp. was Mar

Ultrasphere

compound

MeOH

25.2 MHf.

Coralhu

(Areschoug)

Miramar,

(49:l); 7.

NMR:

marerlal.

rlongata

on Alltech R-Sil

separations were performed

(500x

(250 x 10 mm) columns. Solvents:

C. oficmo/is

Compound

er (I/.

._. 1oOg

J. A. PALERMO P* -J

2986

CL

H-19). 1.82 (3H, s, H-19’). 1.39 (3H. s, H-18’) 1.35 (3H, s, H-17’). 1.23(3H,s. H-18). 1.10(3H,s, H-16’). l.O4(3H,s, H-17),0.97(3H, s. H-16). Acknowledyrmmrs---We thank UMYFOR (CONICET-FCEN) for spectroscopic analysis and CONICET and the Organization of the American States for partial financial support.

REFERENCFS 1. Liaaen-Jensen, S. (1978) Marrne Natural Products, Chemical & Biochemical Perspecfices Vol. 2 (Scheuer. P.. ed.), p. I. Academic Press. 2. Liaaen-Jensen. S. (1985) Pure Appl. Chem. 57, 649. 3. Liaaen-Jensen, S. (1989)Pure Appl. Chem. 61, 369. 4. Bjornland, T. and Aguilar-Martinez. M. (1976) Phyrochemistry 15, 291. Seldcs. A. M.. Deluca, M.. Gros, E. G., Rovirosa, J., San Martm. A. and Darias, J. (1990) Z. Narurforsch. 45, 83. Bonnett, R., Mallams, A., Spark, A., Tee, J., Weedon, B. and McCormick. A. (1969)J. Chem. Sot. (C) 429. Englert, G. (1982) Carorenoid Chemistry nnd Biochemisrr) (Britton, G. and Goodwin, T., eds), p. 107. Pergamon Press, Oxford.

“I.

8. Englert. G. (1985) Pure Appl. Chem. 57, 801. 9. Bernhard, K., Moss, G. P.. T6th. Gy. and Weedon, Tetrahedron

Letters

B. (1974)

3899.

10. Bjornland, T.. Englert, G.. Bernhard, K. and Liaaen-Jensen, S. (1989) Teetruhedron Letters 2577. 11. Cadosch, H.. Viigeli, U., Riiedi, P. and Eugstcr. C. (1978) He/r:. Chim. Acra 61, 783. 12. Cadosch, H., Vdgcli, 1J.. Riiedi. P. and Eugster, C. (1978) He/c. Chim. Acra 61, 151 I.

13. Acemoglu, M., Prewo, R., Bieri, J. and Eugster, C. (1984) Ilela. Chim. Acta 67, 175. 14. Budzikiewicz. H. (1982) Carorenoid Chemistry and Biochemisrry (Britton, G. and Goodwin, T.. eds), p. 155. Pergamon Press, Oxford. 15. Marki-Frschcr, E., Bucheker. P., Eugster, C.. Noack, K. and Vecchi, M. (1982) Hell. Chim. Actu 65, 2198. 16. Strain. H. H. (195 I) Manual of Phycology (Smith, G.. ed.), p. 243. Chronica Botanica, Waltham, Mass. 17. Carter. P. Heilbron. I. and Lythgoe. B (1939) Proc. Roy. Sot. B12.8, 82. 18. Czeczuga, B. (1983) Blochem. Sysr. Ecol. 11, 329. 19. Bjornland. T., Borch. G. and baaen-Jensen. S. (1984)Phyrochemisrry

23, I7

I I,