Oxygenated C17 polyacetylene metabolites from Algerian Eryngium tricuspidatum L. roots: Structure and biological activity.

The secondary metabolite pattern of Eryngium tricuspidatum has been found to be dominated by C17 acetylene oxylipins, according to the chemistry reported in the literature for the genus Eryngium. Two new oxylipins, 11-acetoxy-falcarindiol (4) and 1,2-dihydro-11-acetoxy-falcarindiol (5) have been isolated, along with main related polyacetylenes 1-3 and the already known monoterpene aldehydes 6-10, from the petroleum ether extract of roots. The structure and the absolute configuration of compounds 4 and 5 have been determined by spectroscopic methods as well as by comparison with related known compounds. Polyacetylenes 1-4 inhibited significantly the in vitro growth of a series of cancer cell lines, ranging from 0.3 to 29 µM, whereas 5 was inactive.

Effect of heat treatments on biomolecular profile of Sardinian apple cultivars.

Postharvest heat treatments (hot water or hot air treatment) may be applied to horticultural crops to control fungal diseases, insect infestation and to reduce chilling injury in cultivars susceptible to low storage temperatures. The present study investigated the influence of hot water (53 degrees C for 60s) and hot air treatment (38 degrees C for 24h) applied to two typical Sardinian apple varieties, cvs. Miali and Caddina, on the composition of the lipophilic extracts of the peel as well as on the antioxidant activity of ethanolic extracts of both peel and pulp. The lipophilic extracts of the peel of the two varieties were almost similar and resulted to be dominated by the presence of triterpenes being ursolic and oleanoic acids the main metabolites in both analysed fruits. The chemical analysis of the extracts obtained from the different heat-treated samples for each variety revealed no significant difference in the relative distribution of triterpene components with respect to untreated control samples. This strongly suggested that heat treatment does not affect the composition of terpene metabolite profile of the fruit peel. On the other hand, the antioxidant activity of the ethanolic extracts of the peel and the pulp of heat treated was significantly different from that of control In particular, on Caddina variety the antioxidant activity levels of the peel were consistently higher than in the pulp and were affected by storage conditions. Differently, on Miali variety the antioxidant activity of heat-treated samples was higher than control sample in both peel and pulp.

A new xenicane norditerpene from the Indian marine gorgonian Acanthogorgia turgida.

Chemical investigation of the liposoluble extract of the gorgonian Acanthogorgia turgida, from Indian coasts, led us to isolate a new xenicane-based norditerpene, isoacalycixeniolide-A (1), along with the known structurally related compounds 2-6. The structure of the norditerpene (1) was elucidated by spectral methods (mainly by NMR techniques), whereas the absolute stereochemistry was suggested by the application of circular dicroism methodology.

Novel inhibitors of mitochondrial respiratory chain: endoperoxides from the marine tunicate Stolonica socialis.

The Mediterranean tunicate Stolonica socialis contains a new class of powerful cytotoxic acetogenins, generically named stolonoxides. In this paper, which also details the isolation and chemical characterization of a minor component (3a) of the tunicate extract, we report the potent inhibitory activity (IC(50) < 1 microM) of stolonoxides (1a and 3a) on mitochondrial electron transfer. The compounds affect specifically the functionality of complex II (succinate:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome C oxidoreductase) in mammalian cells, thereby causing a rapid collapse of the whole energetic metabolism. This result, which differs from the properties of similar known products (e.g., 6), reflects the molecular features of stolonoxides.

Scalarane and homoscalarane compounds from the nudibranchs Glossodoris sedna and Glossodoris dalli: chemical and biological properties.

A series of homoscalarane and scalarane compounds (2-7) have been isolated from two distinct species of Pacific Glossodoris nudibranchs. The structure and elucidation of the relative stereochemistry of the new metabolites 2 and 3 were obtained by spectroscopic methods. Compound 2 was ichthyotoxic at 0.1 ppm against Gambusia affinis and showed moderate activity (IC(50) 18 microM) to inhibit mammalian phospholipase A(2).

Three new butenolide lipids from the caribbean gorgonian pterogorgia anceps

Three novel fatty acid derivatives (1-3), containing one or two butenolide moieties, were isolated from the Caribbean gorgonian Pterogorgia anceps and chemically characterized by spectroscopic methods and comparison with known compounds. The new molecules were structurally related to ancepsenolide (4), a typical metabolite from Pterogorgia species, which was not detected in this collection of P. anceps.

New minor diterpenoid diacylglycerols from the skin of the nudibranch anisodoris fontaini

The Patagonian dorid nudibranch Anisodoris fontaini contains in its mantle a series of isocopalane diterpenoid diacylglycerols. Five new minor metabolites, anisodorins 1-5 (1-5), along with the already reported 6 and 7, have been isolated and chemically characterized. The structure and the relative stereochemistries have been determined by spectroscopic means, while the absolute stereochemistries for 2-5 are suggested to be the same as for the biogenetically related major compounds 6 and 7. Synthesis of the enantiomer (8) of anisodorin 1 confirmed the proposed structure and absolute stereochemistry.

Further Petroformynes from Both Atlantic and Mediterranean Populations of the Sponge Petrosia ficiformis

Five novel polyacetylenes (5-9) were isolated from two different populations of the sponge Petrosia ficiformis collected in the Mediterranean Sea and the Atlantic Ocean. Their structures were established by extensive NMR analysis and by comparison with known petroformynes.

Novel diterpenoid diacylglycerols from marine molluscs: potent morphogens and protein kinase C activators.

Five novel 1,2-sn-diacylglycerols with diterpenoid acyl moieties in the sn-1 position were isolated and characterized, together with the corresponding 1,3-sn-diacylglycerols, from three species of dorid nudibranchs molluscs. Their potent activity as morphogens in vivo in the Hydra tentacle regeneration assay and their parallel activity as activators of rat brain protein kinase C (PKC) in vitro are reported here. Our findings promote the use of these compounds as useful molecular probes for both in vivo and in vitro studies on the participation of PKC in cell development.

4-acetylaplykurodin B and aplykurodinone B, two ichthyotoxic degraded sterols from the Mediterranean mollusk Aplysia fasciata.

Two ichthyotoxic lactones, 4-acetylaplykurodin B [1] and aplykurodinone B [2], were isolated from the external parts of the body of the mollusk Aplysia fasciata. Their structures, determined by spectroscopic and chemical means, are closely related to aplykurodin B [3] previously isolated from Aplysia kurodai. The interconversion of delta- and gamma-lactones in the aplykurodin derivatives has been also investigated.

Ichthyotoxic diterpenoids from the Cantabrian nudibranch Chromodoris luteorosea.

Five spongian diterpenoids 2, 3, 6-8, previously found in sponges and nudibranchs from very distinct geographical areas, have been isolated from the Cantabrian nudibranch Chromodoris luteorosea. The terpenoids are mainly localized along the border of the mantle of the mollusk. All the diterpenoids are toxic to Gambusia affinis.

Antimicrobial and antiviral activity of xylosyl-methylthio-adenosine, a naturally occurring analogue of methylthio-adenosine from Doris verrucosa.

Xylosyl-methylthio-adenosine, a naturally occurring analogue of 5'-deoxy-5'-methylthio-adenosine, has been postulated to play a protective role during egg development in the mollusc Doris verrucosa. However, in vitro tests showed that this analogue is devoid of activity against fungi, bacteria and viruses.

The effect of diterpenoidic diacylglycerols on tentacle regeneration in Hydra vulgaris.

1. The effect of two ichthyotoxic diterpenoid diacylglycerols, verrucosins A and B, previously isolated from the mantle of a marine nudibranch mollusc, were studied on Hydra vulgaris tentacle regeneration. 2. A potent effect was found for both verrucosins in the low nanomolar range; the rank of potency observed was analogous to that reported for diglycerid activation of protein kinase C and to that found for verrucosin activation of this enzyme. 3. In the high nanomolar range, the two verrucosins were found to be toxic to Hydra vulgaris. 4. Verrucosin B-induced toxicity and tentacle regeneration were found to be dependent on [Ca2+] in the assay medium.

Defensive strategy of twoHypselodoris nudibranchs from Italian and Spanish coasts.

Hypselodoris nudibranchs from different geographic areas (Spain and Italy) have been studied in order to investigate their general defensive strategy. Longifolin (1) and nakafuran-9 (2) are the main ichthyodeterrent allomones used by the mollusks to avoid predation. Evidence of their dietary origin is presented and the very effective strategy against predators, which includes secretion of allomones into the mucus and their storage into specific mantle dermal formations (MDFs), is also discussed.

Oxytoxins, bioactive molecules produced by the marine opisthobranch mollusc Oxynoe olivacea from a diet-derived precursor.

The ethereal extract of the mucous secretion from the opisthobranch mollusc Oxynoe olivacea was examined and found to contain two novel ichthyotoxic compounds, named oxytoxin 1 and 2 (1,2). The structures of 1 and 2 are closely related to the metabolites previously isolated from the alga Caulerpa prolifera. The activity of the most stable compound was studied in order to investigate the possibility of a further biological role for these metabolites, which represent an uncommon example of bioactive molecules produced in vivo from a dietary precursor.

Biosynthesis and metabolism of 9-[5'-deoxy-5'-(methylthio)-beta-D-xylofuranosyl]adenine, a novel natural analogue of methylthioadenosine.

The biosynthesis of 9-[5'-deoxy-5'-(methylthio)-beta-D-xylofuranosyl]adenine (xylosyl-MTA), a naturally occurring analogue of 5'-deoxy-5'-methylthioadenosine (MTA) recently characterized, was studied in the nudibranch mollusc Doris verrucosa. Experiments performed in vivo with putative labelled precursors such as [8-14C]adenine, [Me-14C]methionine and [Me-14C]MTA indicate that xylosyl-MTA originates from MTA. Experiments with MTA double-labelled at critical positions are consistent with a 3'-isomerization of the nucleoside through the formation of a 3'-oxo intermediate. In addition, experiments with the newly synthesized [3'-3H]xylosyl-MTA are indicative for a very low turnover rate of this molecule, which therefore accumulates in the mollusc.

Insect antifeedant activity and hot taste for humans of selected natural and synthetic 1,4-dialdehydes.

The antifeedant activity towards larvae of Leptinotarsa decemlineata and Spodoptera littoralis and the hot taste for the human tongue have been determined for natural and synthetic 1,4-dialdehydes. Among the bicyclic dialdehydes the biological activity has been found to be dependent on the distance between the two aldehyde groups; tricyclic and pentacyclic dialdehydes are inactive in both tests. A short synthetic route to (-)- and (+)-polygodial is reported.