Structural and Stereochemical Studies on Brominated Meroterpenoids From the Dictyoceratid Sponge Cacospongia sp.

Abstract

The structures of seven minor metabolites, (5)-(11), from the encrusting sponge Cacospongia sp. Were deduced by 1H, 13C and mass spectrometric data. Compounds (5)-(7) are hydroxy derivatives of the previously isolated tribromocacoxanthene (1); their relative stereochemistry was determined from 1H-1H coupling information. Compounds (8)-(11) represent an alternative cyclization mode of a cyclocymopol-related precursor (15) and possess a spiro-fused bicyclic ring system; the relative stereochemistry of (8)-(10) was deduced by 1H n.O.e. difference spectroscopy. The biological role of brominated meroterpenoids in Cacospongia sp. is discussed.

High Amounts of Halogenated Natural Products in Sperm Whales (Physeter macrocephalus) from Two Italian Regions in the Mediterranean Sea

“…Their semiquantified concentrations ranged from undetectable to ∼40 ng/g dry weight in the samples from the Mediterranean coast . PBHDs and the PBHD related compounds were almost exclusively found in the samples from the Mediterranean Sea, which supports that PBHD derivatives producing sponges are found throughout the Mediterranean Sea as well as in Oceania. ,,, …”

“…45 PBHDs and the PBHD related compounds were almost exclusively found in the samples from the Mediterranean Sea, which supports that PBHD derivatives producing sponges are found throughout the Mediterranean Sea as well as in Oceania. 4,33,41,45 Given the rather narrow PBHD contamination range (see above), no deviation could be made between the different sampling sites. Also, the highest and the lowest PBHD contamination was observed in two adult individuals (samples A6 and A7) from the same site (1, Figure 1).…”

New Sesterterpene Metabolites from the Mediterranean Sponge Cacospongia scalaris

“…linteiformis from the Caribbean yielded a series of bi-, tetra-, and pentacyclic sesterterpenes, 14,15 while Australian collections have been reported to yield a number of brominated meroterpenoids. 16,17 Finally, a Philippine Cacospongia species produced furanolabdanes and furanoditerpenes as well as diterpene-benzenoids which have not been detected in this genus before. 18 In the course of our investigations on bioactive metabolites from marine organisms and the elucidation of their ecological roles 19,20 we were intrigued by the geographic variability in the chemistry of Cacospongia.…”

“…Specimens of C. cf. linteiformis from the Caribbean yielded a series of bi-, tetra-, and pentacyclic sesterterpenes, , while Australian collections have been reported to yield a number of brominated meroterpenoids. , Finally, a Philippine Cacospongia species produced furanolabdanes and furanoditerpenes as well as diterpene-benzenoids which have not been detected in this genus before …”

Biological Effects and Biosynthesis of Brominated Metabolites

“…Examples from a wide range ofbiota including a bacterium, algae, a fungus, and sponges including Cacospongia sp. [ 10] are given in Table 17 and Table 18 and their biosynthesis in Fig. 60a- Br A note of caution should be entered since in some cases both a quinone and the corresponding hydroquinone may be present so that either cationoid bromination of the phenol or anionoid bromination of the quinone may take place: an illustrative example is bromopuupenone (637) that could also be produced by anionoid bromination of the quinone (Fig.…”