Meroterpenes from marine invertebrates: structures, occurrence, and ecological implications

Meroterpenes are widely distributed among marine organisms; they are particularly abundant within brown algae, but other important sources include microorganisms and invertebrates. In the present review the structures and bioactivities of meroterpenes from marine invertebrates, mainly sponges and tunicates, are summarized. More than 300 molecules, often complex and with unique skeletons originating from intra- and inter-​mol. cyclizations, and(or) rearrangements, are illustrated. The reported syntheses are mentioned. The issue of a potential microbial link to their biosynthesis is also shortly outlined

Further Investigation of the Mediterranean Sponge Axinella polypoides: Isolation of a New Cyclonucleoside and a New Betaine

An exhaustive exploration into the metabolic content of the Mediterranean sponge Axinella-polypoides resulted in the isolation of the new betaine 5 and the new cyclonucleoside 8. The structures of the new metabolites were elucidated by spectroscopic methods assisted by computational methods. The analysis also provided evidence that the sponge does not elaborate pyrrole-imidazole alkaloids (PIAs) but, interestingly, it was shown to contain two already known cyclodipeptides, compounds 9 (verpacamide A) and 10

ε Form Gels and Aerogels of Syndiotactic Polystyrene

Mixtures of two solvents allow obtaining stable physical gels of syndiotactic polystyrene (s-PS), whose physical knots are for the first time constituted by ε cocrystals. These ε gels, by simple scCO2 extraction procedures, lead to aerogels only exhibiting the nanoporous-crystalline ε form, with a degree of crystallinity higher than 45%. This preparationprocedure is the first one leading to pure ε form aerogels. Although the BET surface areas for ε aerogels (exhibiting crystalline nanochannels) are much lower than for δ form aerogels (exhibiting isolated crystalline nanocavities), the uptake of long organic molecules is definitely higher for ε aerogels, with differences becoming very high at low guest pressures. Moreover, for all guests, pure ε aerogels present uptakes significantly higher than the previously known ε + γ aerogels

Bioactive Alkaloids of Marine Origin

The marine organisms, mainly invertebrates such as sponges and ascidians, are a rich source of varied natural alkaloids with unique chemical scaffolds and diverse bioactivities. From a medicinal chemistry perspective, the marine alkaloids' fascinating structures as well as their broad spectrum of pharmacological activity make them promising lead compounds for various druggable targets. The recent results in the field of marine alkaloids are thus here described. The structures and biological activities of selected typical classes of marine alkaloids are briefly illustrated, with the emphasis on the role of these natural products as leads for drug discovery

Intercalate Co-Crystals of Syndiotactic Polystyrene with Benzyl methacrylate and Radiation-Induced Guest Polymerization

The formation of a cocrystalline phase of syndiotactic polystyrene (s-PS), presenting layers of benzyl methacrylate (BzMA) guest molecules intercalated with layers of closely packed alternated enantiomorphous polymer chains, is presented. The distance between these polymer layers, which for the nanoporous δ phase of s-PS is of 1.05 nm increases up to 1.61 nm, due to the guest intercalation. The proximity of theBzMA molecules in the guest layers makes possible their irradiation-induced polymerization inside the cocrystalline film. The polymerization products are expelled from the crystalline host phase, and the latter, as a consequence of guest exclusion, reorganizes in a lower order helical mesomorphic phase