Pseudopterogorgia elisabetha

A recent example demonstrates that corals rely on induced biosynthesis of terpenes as a dynamic defense strategy as well. The induction of terpenoid secondary metabolites was observed in the sea whip Pseudopterogorgia elisabethae [162]. Levels of pseudopterosins 89-92, a group of diterpene glycosides with anti-inflammatory and analgesic properties (Scheme 23) [163-165], are increased in response predation by the mollusk Cyphoma gibbosum. First bioassays indicate that these natural products are involved in the chemical defense. 

Scheme 23 Inducible pseudopterosins in the sea whip Pseudopterogorgia elisabethae...

Abstract Recent chemical studies on the marine soft corals and terrestrial plants have lesnlted in the isolation of several novel componnds. The soft corals, Pseudopterogorgia elisabethae and Cladiella species yielded several novel terpenoids, exhibiting antimicrobial activities. New steroids were isolated from terrestrial fungi, Mucor plumbeus and Coprims micaceus. Phytochemical studies on the Buxus hyrcana, collected from Iran, have yielded steroidal bases. This revdew describes the new natiual products exhibiting different bioactivities from the aforementioned sources. 

Buxus hyrcana, Cladiella, Coprinus micaceus, coral, marine, Mucor plumbeus, Pseudopterogorgia elisabethae, steroids, terpenoids, terrestrial... 

Keywords Pseudopterogorgia elisabethae Marine natnral prodncts ... 

Marine Natural Products from Pseudopterogorgia elisabethae 3... 

The following gives an overview of the natural products isolated to date from Pseudopterogorgia elisabethae. The structures of these compounds were proposed on the basis of comprehensive spectral analyses, chemical transformations, and X-ray crystallographic analyses. 

Compounds from Pseudopterogorgia elisabethae can be classified according to their carbon skeletons. So far 15 carbon skeletons have been identified which are based on the serrulatane skeleton. Various cyclizations (see also Sect. 3.1, Scheme 1) of this precursor lead to newpolycycHc structures (e.g., amphilectanes, ehsabethanes, etc.) that are starting points for new degradation products (seco-, nor-, bisnor-, etc. compoimds). 

A C9-C14 cycHzation forms the ring C and leads to the amphilectane skeleton which is foimd for instance in pseudopterosins A-F (10, aglycone) [10] isolated from Pseudopterogorgia elisabethae extracts stemming from a Bahamian collection site (Fig. 5). This class of natural products can be characterized as... 

A further tetracyclic metabolite from Pseudopterogorgia elisabethae possessing the unprecedented cage-like colombiane carbon skeleton is represented by colombiasin A (36) [21]. The ring D of the colombiane skeleton arises from a C12-C2 cyclization of an elisabethane-based precursor. Experimental data were not obtained to define the absolute stereochemistry of 36 this task was later accomplished by total synthesis (see Sect. 4.6). 

As shown in the previous section, the structural diversity found among the plethora of natural products isolated from Pseudopterogorgia elisabethae is indeed remarkable. Scheme 1 gives an overview of the biosynthetic pathways to the different carbon frameworks produced by Pseudopterogorgia elisabethae. 

An alternative pathway (Scheme 8) could start from the two regioisomers 5 and 6, both isolated from Pseudopterogorgia elisabethae. Thus, after phosphorylation or protonation followed by elimination to dienylquinone 46, intramolecular cyclization would generate zwitterionic intermediate 47. Hydride... 

The pseudopterosins and seco-pseudopterosin isolated from Bahamian specimens of Pseudopterogorgia elisabethae display strong anti-inflammatory and analgesic activity. These diterpene glycosides had potencies superior to those of... 

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