Mediterranean Sponge Reniera Sarai Research Articles

Synthesis of (-)-Sarain A

(-)-Sarain A is an alkaloid isolated from the Mediterranean sponge Reniera sarai and exhibits antibacterial, insecticidal and antitumor activity. The Overman group reports the first total synthesis of this structurally complex alkaloid.

Comparative antibacterial activity of polymeric 3-alkylpyridinium salts isolated from the Mediterranean sponge Reniera sarai and their synthetic analogues

Metabolites from marine sponges are considered a promising alternative to heavy metals in antifouling coatings. Water-soluble polymeric 3-alkylpyridinium salts and 14 related synthetic analogues showed considerable antibacterial activity against marine biofilm bacteria and may represent good candidates as natural biocides for marine technology applications.

Synthesis and bioactivity of linear oligomers related to polymeric alkylpyridinium metabolites from the Mediterranean sponge Reniera sarai.

Dimers and tetramers of linear 3-alkylpyridinium salts have been synthesized by an efficient synthetic pathway, which is also applicable to the preparation of higher oligomers. Mono-, di- and tetrameric compounds have been tested for antibacterial and hemolytic activities and for the inhibition of acetylcholinesterase and protein phosphatase 2A. Their activities were compared to those of the natural poly-3-octylpyridinium alkaloids isolated from the Mediterranean sponge Reniera sarai. Relatively high antibacterial and anti-acetylcholinesterase activities were observed that increase with higher degrees of oligomerization.

Non-toxic Antifouling Activity of Polymeric 3-alkylpyridinium Salts from the Mediterranean Sponge Reniera sarai (Pulitzer-Finali)

The antifouling activity and toxicity of polymeric 3-alkylpyridinium salts (poly-APS) isolated from the Mediterranean sponge Reniera sarai were studied. The activity of these natural products was compared to that of zinc and copper complexes of pyrithione, two non-persistent booster biocides successfully used in current antifouling coatings. Larvae of Balanus amphitrite (cyprids and nauplii) were used to monitor settlement inhibition and the extent to which inhibition was due to toxicity. The microalga Tetraselmis suecica and larvae of the mussel Mytilus galloprovincialis were used in toxicity bioassays. Compared to the booster biocides, poly-APS were less effective at inhibiting cyprid settlement, but their effects were non toxic and reversible, with very low toxicity against the organisms used in the toxicity bioassays. Although encouraging, these results are not enough to warrant the use of poly-APS as a potential commercial antifoulant. They however justify possible future efforts to chemically synthesize poly-APS analogues for further tests.

Absolute stereochemistry of isosaraine-1 and isosaraine-2

The absolute stereochemistry of the quinolizidone systems present in the marine macrocyclic alkaloids isosaraine-1 ( 3) and isosaraine-2 ( 4), minor metabolites of the Mediterranean sponge Reniera sarai, has been established by applying advanced Mosher's method to the alcohol derivatives ( 5 and 6).

Further studies of alkaloids from Reniera sarai: Structures of saraine-3 and isosaraine-3; absolute stereochemistry of saraine-1 and saraine-2

A new macrocyclic diamine alkaloid, named isosaraine-3 ( 9), has been isolated from the Mediterranean sponge Reniera sarai. The structures of both this new compound and saraine-3 ( 6), until now only partially clarified, have been completely elucidated by extensive spectroscopic studies. The absolute stereochemistry of the quinolizidone systems present in the co-occurring major alkaloids, saraine-1 ( 4) and saraine-2 ( 5), has been determined by applying advanced Mosher's method to the alcohol derivatives ( 10–13).

Structural and stereochemical studies of saraines: Macrocyclic alkaloids of the sponge Reniera sarai

The absolute stereochemistry of saraines A-C ( 2–4), a class of unusual polycyclic alkaloids from the Mediterranean sponge Reniera sarai, has been elucidated by applying high field 1H-NMR to Mosher's method. The structures of saraine-B ( 3) and saraine-C ( 4), only partially clarified previously, now have been fully characterized by extensive analysis of their NMR spectra.

Selected biological activities of saraines

1. 1. The Mediterranean sponge Reniera sarai, Pulitzeri-Finali, 1969 (Demospongiae: Haploscleridae: Renieridae) posseses in large amounts a series of unprecedented polycyclic alkaloids, saraines 1–3 and saraines A–C. 2. 2. The structural peculiarities of saraines, their chemical-physical characteristics, along with their relevant abundance in the sponge, prompted a study aimed at investigating their biological properties. 3. 3. Saraines were assayed for their cytotoxic, antibacterial, insecticidal and potential antitumoral activities. These results, along with the growth inhibition of fertilized sea urchin eggs, are reported.

ChemInform Abstract: Unprecedented Alkaloid Skeleton from the Mediterranean Sponge Reniera sarai: X‐Ray Structure of an Acetate Derivative of Sarain‐A

Abstract The Mediterranean sponge Reniera sarai is a rich source of new alkaloids. Until now the study has been limited to the less polar compounds. In this paper we report the first studies on the more polar UV absorbing alkaloid fraction, which resulted a mixture of threehomologs, sarains A-C. A resolutive X-ray study on an acetate derivative of sarain-A has descovered an unprecedented alkaloid skeletonexhibiting a central cage structure, characterized by a chargedpseudobase moiety, in the middle of two cyclic alkyl chains.

Unprecedented alkaloid skeleton from the mediterranean sponge reniera sarai: X-ray structure of an acetate derivative of sarain-a

The Mediterranean sponge Reniera sarai is a rich source of new alkaloids. Until now the study has been limited to the less polar compounds. In this paper we report the first studies on the more polar UV absorbing alkaloid fraction, which resulted a mixture of threehomologs, sarains A-C. A resolutive X-ray study on an acetate derivative of sarain-A has descovered an unprecedented alkaloid skeletonexhibiting a central cage structure, characterized by a chargedpseudobase moiety, in the middle of two cyclic alkyl chains.