Callyptide A, a new cytotoxic peptide from the Red Sea marine sponge <i>Callyspongia</i> species

<p>In the course of our continuing efforts to allocate bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge <i>Callyspongia</i> species. The cytotoxic dichloromethane fraction of the methanolic extract of the sponge afforded a new cytotoxic peptide named callyptide A (<b>1</b>). Its structure was determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determination. The configuration of the amino acids was determined by Marfey’s analysis. Callyptide A was found to exhibit growth inhibitory activity when tested against different cancer cell lines.</p

Apratoxin H and Apratoxin A Sulfoxide from the Red Sea Cyanobacterium <i>Moorea producens</i>

Cultivation of the marine cyanobacterium <i>Moorea producens</i>, collected from the Nabq Mangroves in the Gulf of Aqaba (Red Sea), led to the isolation of new apratoxin analogues apratoxin H (<b>1</b>) and apratoxin A sulfoxide (<b>2</b>), together with the known apratoxins A–C, lyngbyabellin B, and hectochlorin. The absolute configuration of these new potent cytotoxins was determined by chemical degradation, MS, NMR, and CD spectroscopy. Apratoxin H (<b>1</b>) contains pipecolic acid in place of the proline residue present in apratoxin A, expanding the known suite of naturally occurring analogues that display amino acid substitutions within the final module of the apratoxin biosynthetic pathway. The oxidation site of apratoxin A sulfoxide (<b>2</b>) was deduced from MS fragmentation patterns and IR data, and <b>2</b> could not be generated experimentally by oxidation of apratoxin A. The cytotoxicity of <b>1</b> and <b>2</b> to human NCI-H460 lung cancer cells (IC₅₀ = 3.4 and 89.9 nM, respectively) provides further insight into the structure–activity relationships in the apratoxin series. Phylogenetic analysis of the apratoxin-producing cyanobacterial strains belonging to the genus <i>Moorea</i>, coupled with the recently annotated apratoxin biosynthetic pathway, supports the notion that apratoxin production and structural diversity may be specific to their geographical niche

Low and magnified power of rat paw sections stained by H&E, (a) Control group, E: epidermis, D: dermis with no signs of vascular congestion or inflammatory cells (dotted square) with normal capillaries (black arrows) and connective tissue dermis (stars). (b) Carrageenan group, showing marked inflammatory infiltration in the deep dermis (D), capillary dilation and congestion with neutrophils margination prior to escape into the surrounding tissue (arrows;) (c) <i>Xestospongia testudinaria</i> methanolic extract group, showing significant decrease of the inflammatory cells in the dermis and within blood vessels. (d) Indomethacin group, showing a decrease in both inflammatory cells infiltration and vascular congestion.

<p>Low and magnified power of rat paw sections stained by H&E, (a) Control group, E: epidermis, D: dermis with no signs of vascular congestion or inflammatory cells (dotted square) with normal capillaries (black arrows) and connective tissue dermis (stars). (b) Carrageenan group, showing marked inflammatory infiltration in the deep dermis (D), capillary dilation and congestion with neutrophils margination prior to escape into the surrounding tissue (arrows;) (c) <i>Xestospongia testudinaria</i> methanolic extract group, showing significant decrease of the inflammatory cells in the dermis and within blood vessels. (d) Indomethacin group, showing a decrease in both inflammatory cells infiltration and vascular congestion.</p

Effect of <i>Xestospongia testudinaria</i> methanolic extract (100 mg/kg) and indomethacin (10 mg/kg) on paw GPX, SOD and CAT enzymes activity measured in carrageenan-induced rat hind paw edema.

<p>Data are mean ± SD (n = 6).</p><p>^a Significant versus control (P ≤ 0.05).</p><p>^b Significant versus carrageenan (P ≤ 0.05).</p><p>Effect of <i>Xestospongia testudinaria</i> methanolic extract (100 mg/kg) and indomethacin (10 mg/kg) on paw GPX, SOD and CAT enzymes activity measured in carrageenan-induced rat hind paw edema.</p

Chromatogram obtained from GC-MS with the methanolic extracts of the <i>Xestospongia testudinaria</i>.

<p>Chromatogram obtained from GC-MS with the methanolic extracts of the <i>Xestospongia testudinaria</i>.</p

Total antioxidant capacity of <i>Xestospongia testudinaria</i> methanolic extract at different concentrations in vitro.

<p>Expressed as percent inhibition toward DPPH-induced oxidative stress.</p

Chemical constituents of <i>Xestospongia testudinaria</i> methanolic extract, detected by GC-MS.

<p>Chemical constituents of <i>Xestospongia testudinaria</i> methanolic extract, detected by GC-MS.</p

La Petite presse : journal quotidien... / [rédacteur en chef : Balathier Bragelonne]

03 avril 18841884/04/03 (A18,N6540)

Raman spectroscopy of the chitinous scaffolds isolated from <i>A</i>. <i>wolffgangi</i> and <i>E</i>. <i>gibbosa</i> demosponges in comparison with <i>α</i>-chitin standard.

<p>Raman spectroscopy of the chitinous scaffolds isolated from <i>A</i>. <i>wolffgangi</i> and <i>E</i>. <i>gibbosa</i> demosponges in comparison with <i>α</i>-chitin standard.</p

Discovery of chitin in skeletons of non-verongiid Red Sea demosponges - Fig 4

<p>Spicule-free, colorless 3D scaffold obtained from <i>A</i>. <i>wolffgangii</i> (a) and <i>E</i>. <i>gibbosa</i> (d) according to the isolation procedure represented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0195803#pone.0195803.g003" target="_blank">Fig 3</a>. Microstructural features of selected skeletal fibers of <i>A</i>. <i>wolffgangii</i> (marked with arrows) (b) and <i>E</i>. <i>gibbosa</i> (e) prior and after HF-treatment (c and f, respectively) are well visible on the corresponding light microscopy images.</p