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Sterol Ring System Oxidation Pattern in Marine Sponges

View Article: PubMed Central

ABSTRACT

The marine sponges (Porifera) are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce sterols fitting into one of the four main biogenetic pathways viz., (i) 3β-hydroxy-Δ5-sterol pathway, (ii) 3β-hydroxy-Δ7-sterol pathway, (iii) 3β-hydroxy-Δ5,7-sterol pathway, and (iv) 3α-hydroxy sterol pathway.

No MeSH data available.


Significant biosynthetic reactions caused around 3β-OH; [ ] intermediate.
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f2-marinedrugs-03-00084: Significant biosynthetic reactions caused around 3β-OH; [ ] intermediate.

Mentions: In order to propose biosynthetic relationships, as marine biosynthetic studies are few [6,7], clues are taken from the pathways operating in the terrestrial plants and animals, which are documented quite well, and since the pathways operating in marine organisms should essentially be similar to those operating in terrestrial organisms [8]. In Schemes 1–14 are presented sequential oxidations within the sterol ABCD ring system that should be taking place as part of biogenesis within marine sponges. In each product structure, the center where the structural change has resulted compared to the precursor is shown in red color. The biogenic connectivity between various sterol ring structures although hypothetical is depicted with the arrow (→) sign for clarity although this sign is usually reserved for chemical conversions that actually take place. Most often, each sponge species contains a particular group of polar sterols dominated by a set of closely related biogenetic mechanisms as presented in each scheme. However, since the schemes are formulated basing on the ‘reported’ sterol composition, and since there is occasionally a lack of information on the total sterol composition of the sponge (often, it is only the new compounds that are described), the schemes are subject to refinement.


Sterol Ring System Oxidation Pattern in Marine Sponges
Significant biosynthetic reactions caused around 3β-OH; [ ] intermediate.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756323&req=5

f2-marinedrugs-03-00084: Significant biosynthetic reactions caused around 3β-OH; [ ] intermediate.
Mentions: In order to propose biosynthetic relationships, as marine biosynthetic studies are few [6,7], clues are taken from the pathways operating in the terrestrial plants and animals, which are documented quite well, and since the pathways operating in marine organisms should essentially be similar to those operating in terrestrial organisms [8]. In Schemes 1–14 are presented sequential oxidations within the sterol ABCD ring system that should be taking place as part of biogenesis within marine sponges. In each product structure, the center where the structural change has resulted compared to the precursor is shown in red color. The biogenic connectivity between various sterol ring structures although hypothetical is depicted with the arrow (→) sign for clarity although this sign is usually reserved for chemical conversions that actually take place. Most often, each sponge species contains a particular group of polar sterols dominated by a set of closely related biogenetic mechanisms as presented in each scheme. However, since the schemes are formulated basing on the ‘reported’ sterol composition, and since there is occasionally a lack of information on the total sterol composition of the sponge (often, it is only the new compounds that are described), the schemes are subject to refinement.

View Article: PubMed Central

ABSTRACT

The marine sponges (Porifera) are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce sterols fitting into one of the four main biogenetic pathways viz., (i) 3β-hydroxy-Δ5-sterol pathway, (ii) 3β-hydroxy-Δ7-sterol pathway, (iii) 3β-hydroxy-Δ5,7-sterol pathway, and (iv) 3α-hydroxy sterol pathway.

No MeSH data available.