Nonhalogenated organic molecules from Laurencia algae

The marine red algae of the genus Laurencia have produced more 700 secondary metabolites and exhibited high molecular diversity and intriguing bioactivity. Since the halogenated structures have been comprehensively reviewed previously, this review, covering up to the end of 2012, mainly focuses on the source, structure elucidation, and bioactivity of nonhalogenated organic molecules from Laurencia spp. as well as the relationship between nonhalogenated and halogenated products. Overall, 173 new or new naturally occurring compounds with 58 skeletons, mainly including sesquiterpenes, diterpenes, triterpenes, and C15-acetogenins, are described.The marine red algae of the genus Laurencia have produced more 700 secondary metabolites and exhibited high molecular diversity and intriguing bioactivity. Since the halogenated structures have been comprehensively reviewed previously, this review, covering up to the end of 2012, mainly focuses on the source, structure elucidation, and bioactivity of nonhalogenated organic molecules from Laurencia spp. as well as the relationship between nonhalogenated and halogenated products. Overall, 173 new or new naturally occurring compounds with 58 skeletons, mainly including sesquiterpenes, diterpenes, triterpenes, and C-15-acetogenins, are described

Volatile halogenated metabolites from marine red algae

A significant number of halogenated low molecular weight metabolites have exhibited an impressive array of biological properties ranging from antimicrobial to insecticidal activities. Studies on the natural products chemistry of the red seaweeds were recently stimulated by the discovery of the acyclic monoterpene halomon, which exhibits selective antitumor activity in the National Cancer Institute's human tumor and disease oriented in vitro screen. The present review is a taxonomy based compilation of the available literature on the halogenated volatile metabolites (C1-C10) produced by red seaweeds, with a short description of the reported ecological and pharmaceutical activities. The review begins with a presentation of simple halogenated hydrocarbons and phenols, showing their wide occurrence in rhodophyta, along with a description of simple halogenated lipids in some of the most frequently investigated red algae species and finally focuses on the chemical composition of individual red algae species. © Springer 2005

New cytotoxic sesquiterpenes from the red algae Laurencia obtusa and Laurencia microcladia

Three new sesquiterpenes (1-3), along with five known (5-9), were isolated from the organic extract of the red alga Laurencia obtusa, collected from the coastal rocks of Serifos in the Aegean Sea. A new dimeric sesquiterpene of the cyclolaurane-type (4) along with four previously reported (7, 10-12) metabolites, were isolated from the extract of Laurencia microcladia, collected at Chios island in the North Aegean Sea. The structures and the relative stereochemistry of the compounds are proposed on the basis of their spectral data. The cytotoxicity of the isolated metabolites was evaluated against several cell lines including human tumor cell lines. © 2005 Elsevier Ltd. All rights reserved

Glandulaurencianols A-C, brominated diterpenes from the red alga, Laurencia glandulifera and the sea hare, Aplysia punctata

Glandulaurencianols A and B were isolated from the organic extract of the red alga, Laurencia glandulifera, collected from the island of Crete in South Greece. Investigation of the mollusk, Aplysia punctata, collected from the coast of Nea Makri, Central Greece, resulted in the isolation of glandulaurencianols A and C. The structures of the new metabolites, as well as their relative configurations, were established on the basis of thorough analyses of their spectroscopic data. © 2014 Elsevier Ltd. All rights reserved

Pharmacophore modeling for qualitative prediction of antiestrogenic activity

A ligand-based pharmacophore approach for the prediction of antiestrogenic activity to be used as an in silico screening tool for bioactive compounds including natural products was developed using Catalyst HypoGen. The generated pharmacophore hypothesis (HYPO-7) consisted of five features, namely, one hydrophobic (HY1), two hydrophobic aromatic (HY2), one hydrogen-bond acceptor (HBA), and one hydrogen-bond donor (HBD). HYPO-7 successfully predicted the lack of cytotoxicity of a number of new metabolites isolated from the red alga Laurencia glandulifera. Furthermore, a screening of the Asinex Gold Collection database was performed by coupling HYPO-7 with a docking filtration, which resulted in a restricted set of 12 new scaffolds to be investigated as potential SERMs. The inhibitory activity of these compounds was evaluated in vitro using MCF7 human breast adenocarcinoma cell line. Ten out of the twelve compounds exhibited inhibitory activity with IC50 values between 26 and 188 μM. This result shows that application of HYPO-7 could assist in the selection of potentially active compounds, thus expediting the hit discovery process. © 2009 American Chemical Society

C15 acetogenins with antistaphylococcal activity from the red alga Laurencia glandulifera

Five new C15 eight-membered cyclic ethers (1, 3-6) with a characteristic terminal cis ene-yne moiety, along with the previously reported acetylenic chloro diol (2) were isolated from the organic extract of the red alga Laurencia glandulifera, collected at Crete island in South Greece. Full assignment of all 1H and 13C resonances were carried out by extensive analysis of their NMR spectra. All metabolites were tested for their antistaphylococcal activity and the minimum inhibitory concentrations (MICs) of 2-5 were in the range of 8-256 μg/ml. © 2008 Phytochemical Society of Europe

Tetrahydrofuran acetogenins from Laurencia glandulifera

Five new C15 acetogenin en-ynes (1-5) with a rare tetrahydrofuran moiety and a linear biosynthetic precursor (6) were isolated from an organic extract of Laurencia glandulifera, collected from the island of Crete in the south Aegean Sea. The structures of the new natural products, as well as their relative configuration, were established by means of spectroscopic data analysis. The cytotoxicity of the isolated natural products was evaluated against five human tumor cell lines. © 2009 American Chemical Society and American Society of Pharmacognosy

Pharmacophore modeling for qualitative prediction of antiestrogenic activity

A ligand-based pharmacophore approach for the prediction of antiestrogenic activity to be used as an in silico screening tool for bioactive compounds including natural products was developed using Catalyst HypoGen. The generated pharmacophore hypothesis (HYPO-7) consisted of five features, namely, one hydrophobic (HY1), two hydrophobic aromatic (HY2), one hydrogen-bond acceptor (HBA), and one hydrogen-bond donor (HBD). HYPO-7 successfully predicted the lack of cytotoxicity of a number of new metabolites isolated from the red alga Laurencia glandulifera. Furthermore, a screening of the Asinex Gold Collection database was performed by coupling HYPO-7 with a docking filtration, which resulted in a restricted set of 12 new scaffolds to be investigated as potential SERMs. The inhibitory activity of these compounds was evaluated in vitro using MCF7 human breast adenocarcinoma cell line. Ten out of the twelve compounds exhibited inhibitory activity with IC50 values between 26 and 188 μM. This result shows that application of HYPO-7 could assist in the selection of potentially active compounds, thus expediting the hit discovery process. © 2009 American Chemical Society