Sphaeroane and neodolabellane diterpenes from the red alga Sphaerococcus coronopifolius

Investigation of minor metabolites in the extracts of the red alga Sphaerococcus coronopifolius collected from the rocky coasts of Corfu Island in the Ionian Sea yielded two new diterpene alcohols, sphaerollanes I, and II (1, 2) featuring neodolabellane skeletons, and the new sphaeroane diterpene alcohol 16-hydroxy-9S*-acetoxy-8-epiisosphaerodiene-2 (3), along with two previously reported metabolites 4, 5. The structures of the new natural products, as well as their relative stereochemistry, were elucidated on the basis of extensive spectral analysis, including 2D-NMR experiments. © 2009 by the authors; licensee Molecular Diversity Preservation International

Structure and antibacterial activity of brominated diterpenes from the red alga Sphaerococcus coronopifolius

Four new tetracyclic brominated diterpenes, 1-4, were isolated from the organic extract of Sphaerococcus coronopifolius, collected from the rocky coasts of Corfu Island. The structures of the new natural products, as well as their relative configurations, were elucidated on the basis of extensive spectral analyses, including 2D-NMR experiments. The isolated metabolites were evaluated for their antibacterial activity against a panel of bacteria including multidrug-resistant (MDR) and methicillinresistant Staphylococcus aureus (MRSA) with MIC values in the range of 16-128 μg/ml. © 2010 Verlag Helvetica Chimica Acta AG

Ioniols I and II, tetracyclic diterpenes with antibacterial activity, from Sphaerococcus coronopifolius

Two naturally occurring diterpenes featuring unprecedented tetracyclic skeletons, ioniols I and II (1 and 2, resp.), along with two previously reported metabolites 3 and 4, were isolated from the organic extract of Sphaerococcus coronopifolius collected from the rocky coasts of Corfu island in the Ionian Sea. The structures of the new natural products, as well as their relative configuration, were elucidated on the basis of extensive spectral analysis, including 2D-NMR experiments. The isolated metabolites were evaluated for their antibacterial activity against a panel of Staphylococcus aureus strains, which included multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) strains. © 2010 Verlag Helvetica Chimica Acta AG

Diterpenes with Unprecedented Skeletons from the Red Alga Sphaerococcus coronopifolius

Three previously unknown diterpenes - spirosphaerol (1), anthrasphaerol (2) and corfusphaeroxide (3) - have been isolated from the red alga Sphaerococcus coronopifolius. Their structures were elucidated by spectral analysis, including NMR and MS. The isolated metabolites were evaluated for their in vitro antitumour activities against one murine and five human cancer cell lines. Copyright © 2015 Wiley-VCH Verlag GmbH & Co. KGaA

Brominated diterpenes with antibacterial activity from the red alga Sphaerococcus coronopifolius

Four new brominated diterpenes (1, 2, 4, 5), along with two previously reported metabolites (3, 6), were isolated from the organic extract of Sphaerococcus coronopifolius, collected in Palaiokastritsa Bay at the west coast of Corfu Island. The structures of the new products, as well as their relative configuration, were established by means of spectroscopic data analyses, including 2D NMR experiments. The isolated metabolites were evaluated for their antibacterial activity against a panel of multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) with MICs in the range 0.5-128 μg/mL. © 2008 American Chemical Society and American Society of Pharmacognosy

Cytotoxic bromoditerpenes from the red alga Sphaerococcus coronopifolius

Three new brominated diterpenes (1, 2, 8), along with six previously reported metabolites (3-7, 9), were isolated from the organic extract of Sphaerococcus coronopifolius, collected in Palaiokastritsa bay at the west coasts of Corfu Island. The structures of the new natural products, as well as their relative stereochemistry, were established by means of spectral data analyses, including 2D experiments. The absolute stereochemistry of 2 and 4 as well as the structure revision of the previously reported metabolite 3 were established by X-ray crystallographic analyses. The cytotoxicity of the isolated metabolites was evaluated against the NSCLC-N6-L16 and A549 human lung cancer cell lines. © 2008 Elsevier Ltd. All rights reserved

Nanofibers based on polysaccharides from the green seaweed Ulva Rigida

The nanofiber ability of an ulvan-rich extract, originated from the low cost biomass of the alga Ulva rigida, has been achieved for the first time via electrospinning. Ulvan-based uniform nanofibers were produced by being blended with poly(vinyl alcohol) (PVA). The nanofibers have an average diameter controllable down to 84 nm and present a highly ordered crystalline structure under transmission electron microscopy (TEM). A new complex fiber is created, which results from ulvan-rich extract and PVA ionic assembly and involves borate esters and divalent cations. The spinnability of this anionic sulfated polysaccharide-rich extract in combination with its interesting biological and physicochemical properties can lead to new biomedical applications such as drug release systems. © 2011 Elsevier Ltd. All rights reserved

Terpenes from the Red Alga Sphaerococcus coronopifolius Inhibit the Settlement of Barnacles

In this study, we screened eight terpenes isolated from the organic extract of Sphaerococcus coronopifolius for their antifouling activity in order to find possible new sources of non-toxic or less toxic bioactive antifoulants. The anti-settlement activity (EC 50) and the degree of toxicity (LC 50) of S. coronopifolius metabolites was evaluated using larvae of the cirriped crustacean Amphibalanus (Balanus) amphitrite (cyprids and nauplii) as model organism. For five of eight tested metabolites EC 50 was lower than 5 mg/L. The most promising results were observed for bromosphaerol (3), which expressed an EC 50 value of 0.23 mg/L, in combination with low toxicity levels (LC 50 > 100 mg/L). The therapeutic ratio-an index used to estimate whether settlement inhibition is due to toxicity or other mechanisms-is also calculated and discussed. © 2010 Springer Science+Business Media, LLC

Acetylene sesquiterpenoid esters from the green alga Caulerpa prolifera

Sixteen secondary metabolites of the green alga Caulerpa prolifera have been isolated, and their chemical structures elucidated by analysis of their spectroscopic data. Two groups of metabolites have been established, with either a 1,2-dihydro-(2a-2i) or a 1,2,3,3′-tetrahydro-2,3-didehydro (3a-3f) caulerpenyne carbon backbone. The terminal vinyl acetoxy group of caulerpenyne was substituted by various fatty acid residues. The antifouling activity of the algal extract was tested in laboratory assays against two of the major groups of fouling organisms (bacteria, microalgae)

Structure and in vitro antitumor activity evaluation of brominated diterpenes from the red alga Sphaerococcus coronopifolius

A novel bromoditerpene methyl ketone (1), two new bromoditerpene alcohols featuring a neodolastane (2), and a bromocorodienol skeleton (3), along with 13 previously reported metabolites (4-16) were isolated from the organic extract of Sphaerococcus coronopifolius collected from the rocky coasts of Corfu island in the Ionian Sea. The structures of the new natural products, as well as their relative stereochemistry, were elaborated on the basis of extensive spectral analysis, including 2D NMR experiments. The absolute stereochemistry of metabolite 3 was determined using the modified Mosher's method. The isolated metabolites were evaluated for their antitumoral activity against four human apoptosis-resistant (U373, A549, SKMEL-28, OE21) and two human apoptosis-sensitive (PC-3, LoVo) cancer cell lines with IC50 in vitro growth inhibitory concentrations in the range 3-100 μM. © 2009 Elsevier Ltd. All rights reserved