Diterpenes from the Gorgonian Coral Erythropodium caribaeorum from the Southern Caribbean

Abstract

ABsmcr.-Erythpodium c u r i b m m obtained off the coast of Tobago has yielded the known diterpenes erythrolide A 111, erythrolide B 121, and erythrolide E 137 as well as a new diterpene designated erythrolide J [4]. T h e structure of compound 4 was determined by high resolution nmr studies.Well over one hundred diterpenes possessing the briarane skeleton have been isolated from marine coelenterates mainly from the sub-class Octocorallia (1). Recent reports of seven new compounds of this type from Erytbropodium caribaemm Duchassaing & Michelotti (Gorgonidae) and nine from a Briareum sp. as well as twenty-five from the encrusting gorgonian Solenopodium stecbei collected on the Great Barrier Reef off Australia have added significantly to this group of diterpenes (2,3). E. caribaeorum is an encrusting gorgonian that is not readily distinguished from Briareum asbartinum. Previous investigations of this organism have yielded erythrolidesA-I (2,4). Erythrolides A E11 and B E27 have not been reported thus far from any other organism and may well be chemotaxonomic markers for E. caribaeorum. We report here our investigation of E. caribaeorum collected off the coast of Tobago. In addition to compounds 1 and 2, we also isolated erythrolide E 131 (2) and a new diterpene which we have named erythrolide J {47. Erythrolides A 117, B 127, and E 137 were identified by comparison oftheir respective H-nmr spectral data with those reported in the literature (2,4). The complete 'H and 1 I5 0 1 1 '0 1 2 O b c I 0 3 0 4

Briarane, Erythrane, and Aquariane Diterpenoids from the Caribbean Gorgonian Erythropodium caribaeorum

“…This identified the constitution of 6 as that of a new erythrolide bearing acetoxy groups at C‐2, C‐9, C‐12, and C‐14, respectively, a 3‐hydroxybutanoyl moiety at C‐4, and a Δ 5,6 double bond. Compound 6 is very closely related to erythrolide J ( 12 ), reported by Dookran et al,2c which differs from 6 only by the nature of the acyl group at C‐4 (a, 3‐acetoxybutanoyl in 12 in place of the 3‐hydroxybutanoyl in 6 ). This relationship was proven by standard acetylation of erythrolide S ( 6 ) which afforded erythrolide J ( 12 ), identical by NMR and [α] D comparison to the authentic material isolated from the same extract.…”

“…Further partitioning of the EtOAc‐soluble materials between n ‐hexane and MeOH/H 2 O, 9:1, yielded 32.5 g of MeOH/H 2 O soluble compounds. Fractionation of the MeOH/H 2 O soluble compounds by sequential application of normal‐phase flash (gradient elution from n ‐hexane/EtOAc, 6:4, to EtOAc to EtOAc/MeOH, 1:1, in 5% increments) and normal‐phase high‐performance liquid chromatographies gave pure samples of erythrolides A ( 1 ),2a B ( 2 ),2a E,2b H,2b J ( 12 ),2c M,2f P ( 14 ),2f Q,2f 16‐acetylerythrolide H,2e and aquariolide A ( 4 ) 6. These known diterpenoids were identified by comparison of their spectroscopic data with those reported in the literature.…”

Metabolic Profiling of the Soft Coral Erythropodium caribaeorum (Alcyonacea: Anthothelidae) from the Colombian Caribbean Reveals Different Chemotypes

“…Compounds 3-15 ( Figure 3) were identified as the known 16-acetyl erythrolide H (3), erythrolide E (4) [24], erythrolide F (5) [24], erythrolide J (6) [7], erythrolide V (7) [9], eleutherobin (8) [26], desmethyleleutherobin (9) [26], erythrolide D (10) [24], erythrolide I (11) [24], erythrolide U (12) [9], erythrolide A (13) [6], erythrolide B (14) [6], erythrolide R (15), by comparing their NMR data with that reported in the literature With all this information, three chemotypes of E. caribaeorum from the Colombian Caribbean Sea were recognized. The Santa Marta chemotype had nine erythrolides, two of them new, together with two eleutherobins.…”

“…Marine diterpenes, in particular, are very interesting due to the fact of their cytotoxic activity, stabilizing microtubules in cancer cells with an activity similar to that of paclitaxel [5]. At least 30 erythrolides and 10 eleutherobin analogs have been identified from samples of E. caribaeorum collected in different places around the Caribbean Sea, such as the Bahamas [4], Belize [6], the Virgin Islands [7], Jamaica [8], Tobago [7], and the Dominican Republic [9]. These organisms have showed a wide variation in their metabolic profile.…”

Marine Environmental Metabolomics

“…Their soft texture seems to make them a target for a range of reef predators, but the many novel compounds they produce act as an effective defence to protect them from these predators. Hence, for example, Erythropodium caribaeorum and Verrucella umbraculum produce several diterpenes B, 7 (Figure 4) [17][18][19][20]. Biomass screening of a new marine-derived strain of Penicillium roqueforti, as produced by liquid-state fermentation, led to the identification of the compound 4-hydroxy-benzaldehyde 8 (0.92%) [21].…”