Novel neuronal nitric oxide synthase (nNOS) selective inhibitor, aplysinopsin-type indole alkaloid, from marine sponge Hyrtios erecta

Two novel aplysinopsin-type indole alkaloids, 1 and 2, and three known indole alkaloids were isolated from the marine sponge Hyrtios erecta. These compounds exhibited selective inhibitory activity against the neuronal isozyme of nitric oxide synthase (nNOS). Furthermore, new quinolone 7 was also isolated from the same marine sponge. The chemical structures of these new compounds were elucidated on the basis of spectroscopic analysis.     

Ceratamines A and B, antimitotic heterocyclic alkaloids isolated from the marine sponge Pseudoceratina sp. collected in Papua New Guinea

[structure: see text] Two novel antimitotic heterocyclic alkaloids, ceratamines A (1) and B (2), have been isolated from the marine sponge Pseudoceratina sp., collected in Papua New Guinea. The structures of 1 and 2 were elucidated by analysis of spectroscopic data.     

Goniomedines A and B: Unprecedented Bisindole Alkaloids Formed through Fusion of Two Indole Moieties via a Dihydropyran Unit

Two novel bisindole alkaloids, goniomedines A (1) and B (2), possessing an unprecedented quebrachamine-pleioarpamine-type skeleton, in which indole moieties are fused via a dihydropyran unit, were isolated from the stem bark of Gonioma malagasy. The structures were elucidated by comprehensive analysis of MS and NMR spectroscopic data. Their absolute configurations were deduced following the comparison of experimental and theoretically calculated ECD spectra and through biogenetic considerations. Goniomedine B (2) exhibited moderate activity against Plasmodium falciparum.     

Daphlongeranines A and B, two novel alkaloids possessing unprecedented skeletons from Daphniphyllum longeracemosum

Two novel alkaloids, daphlongeranines A (1) and B (2), with an unprecedented ring system, were isolated from the fruits of Daphniphyllum longeracemosum. Their unique structures and relative stereochemistries were established on the basis of spectroscopic and single-crystal diffraction analysis. The proposed biosynthetic pathway was also discussed. Compounds 1 and 2 showed weak inhibition on platelet aggregation.     

Simplextones A and B, unusual polyketides from the marine sponge Plakortis simplex

Two novel polyketides, simplextones A (1) and B (2), were isolated from the sponge Plakortis simplex. Their structures were established by spectroscopic methods. The absolute configurations were assigned by modified Mosher's method, X-ray crystallographic analysis, and quantum mechanical calculation of the electronic circular dichroism (ECD) spectrum. Compounds 1 and 2 featured an unprecedented polyketide skeleton via the connection of a single carbon-carbon bond to form a cyclopentane. These compounds also exhibited moderate cytotoxicity.     

Two Novel Poly-Oxygen Bipyridine Alkaloids from Speranskia tuberculata

In a previous paper' we reported two optically active pyridine-2, 6 (l H. 3H)-dionealkatoids speranskalines A and B from SPeranskia luberculala (Bge.) (Euphorbiaceae)We report here the isolation and structural elucidation of two novel poly-oxygenbipyridine alkaloids named speranculatines A (l) and B (2) from this plant.The acetone (or methanol) extract of the air-dried whole plants of .q. IllhelT.lllaluwas subjected to column chromatography on St gel to afford a fraction. whichdemonstrate…     

Cortistatins A, B, C, and D, anti-angiogenic steroidal alkaloids, from the marine sponge Corticium simplex

Four novel steroidal alkaloids named cortistatins A (1), B (2), C (3), and D (4) consisting of a 9(10-19)-abeo-androstane and isoquinoline skeleton have been isolated from the marine sponge Corticium simplex. The absolute stereostructures of 1-4 were elucidated by detailed 2D NMR, CD, and X-ray crystallographic analyses. Cortistatins A-D inhibited proliferation of human umbilical vein endothelial cells (HUVECs) with high selectivity. Among the four substances, cortistatin A (1) showed the strongest anti-proliferative activity (IC50 = 0.0018 muM) against HUVECs, in which the selective index was more than 3000-fold in comparison with that of normal fibroblast or several tumor cell lines.     

Hyrtioseragamines A and B, new alkaloids from the sponge Hyrtios species

Two novel alkaloids with a furo[2,3-b]pyrazin-2(1H)-one moiety and a guanidino group, hyrtioseragamines A (1) and B (2), have been isolated from an Okinawan marine sponge Hyrtios species. The structures of 1 and 2 were elucidated on the basis of spectroscopic data and chemical conversions. Compounds 1 and 2 are the first natural products possessing a furo[2,3-b]pyrazine-related moiety.     

Three new non-brominated pyrrole alkaloids from the South China Sea sponge Agelas nakamurai

Three new non-brominated pyrrole alkaloids,nakamurines A-C(1-3) were isolated from the South China Sea sponge Agelas nakamurai.Their structures were elucidated on the basis of spectroscopic data.Compound 2 showed weak antimicrobial activity against Candida albicans with MIC of 60μg/mL.     

Neuritogenic activity-guided isolation of a free base form manzamine A from a marine sponge, Acanthostrongylophora aff. ingens (Thiele, 1899)

Two manzamine-class alkaloids, manzamine A (1) and 8-hydroxymanzamine (2) were isolated from a Japanese marine sponge Acanthostrongylophora aff. ingens, together with three known alkaloids manzamine E (3), manzamine F (4), and manzamine X (5). The spectral features of 1 and 2 were different from the reported data. Detailed structure analysis using 2D NMR revealed the structure of 1 and 2 as a free base form of hydrochloric salt. These manzamine-class alkaloids showed neuritogenic activity against Neuro 2a cells.     

Novel alkaloids of the aaptamine class from an Indonesian marine sponge of the genus Xestospongia

Four novel alkaloids of the aaptamine class have been isolated in addition to the known aaptamine, isoaaptamine, demethyl(oxy)aaptamine and its dimethylketal from an unidentified species of Indonesian marine sponge of the genus Xestospongia. Their structures were elucidated on the basis of detailed 1D and 2D NMR spectroscopic data. Their antimicrobial activity was tested towards Gram (+) (S. aureus), Gram (−) (E. coli, V. anguillarum) bacterial strains, a fungus (C. tropicalis); their cytotoxic activity was evaluated against KB cells.     

New bromotyrosine alkaloids from the marine sponge Psammaplysilla purpurea

Seven new bromotyrosine alkaloids Purpurealidin A, B, C, D, F, G, H and the known compounds Purealidin Q, Purpurealidin E, 16-Debromoaplysamine-4 and Purpuramine I have been isolated from the marine sponge Psammaplysilla purpurea. Their structure was elucidated on the basis of detailed 1D, 2D NMR and MS spectroscopic data. Purpurealidin B, 16-Debromoaplysamine-4 and Purpuramine I exhibited in vitro antimicrobial activities against E. coli, S. aureus, and V. cholerae. In addition, Purpurealidin B and 16-Debromoaplysamine-4 were also active against Shigella flexineri and Salmonella typhi while Purealidin Q was bactericidal only against Salmonella typhi.     

Novel sesquiterpenes and a lactone from the Jamaican sponge Myrmekioderma styx

Two novel sesquiterpenes, styxone A (1) and styxone B (2), and a novel lactone, styxlactone (3), were isolated from the Jamaican sponge Myrmekioderma styx. Their structures were elucidated by detailed ¹H, ¹³C and 2D NMR data and the absolute stereochemistry of styxone A and B was determined by CD spectra. Styxone A represents a novel sesquiterpene skeleton. (S)-(+)-Curcuphenol (4), (S)-(+)-curcudiol (5), and abolene (6) were also isolated. An activity enhancement by cyanthiwigin B (7) to curcuphenol was observed in the antimicrobial assays when the two compounds were administered together.     

Sebastianines A and B,novel biologically active pyridoacridine alkaloids from the Brazilian ascidian Cystodytes dellechiajei

Fractionation of the crude methanol extract of the ascidian Cystodytes dellechiajei collected in Brazil yielded two novel alkaloids, sebastianine A (1) and sebastianine B (2). The structures of both 1 and 2 were established by analysis of spectroscopic data, indicating an unprecedented ring system for both compounds, comprising a pyridoacridine system fused with a pyrrole unit in sebastianine A (1) and a pyridoacridine system fused with a pyrrolidine system condensed with alpha-hydroxyisovaleric acid in sebastianine B (2). Both alkaloids displayed a cytotoxic profile against a panel of HCT-116 colon carcinoma cells indicative of a p53 dependent mechanism.     

Yaku'amides A and B, cytotoxic linear peptides rich in dehydroamino acids from the marine sponge Ceratopsion sp

Two cytotoxic peptides, yaku'amides A (1) and B (2), were isolated from the marine sponge Ceratopsion sp. Their planar structures were elucidated on the basis of spectroscopic data, whereas the absolute configurations were determined by a combination of the Marfey's analysis and dansylation analysis of the total and partial acid hydrolysis products. The growth inhibitory profile of yaku'amide A against a panel of 39 human cancer cell lines was clearly unique and distinguished from other anticancer drugs.     

Henrycinols A and B,Two Novel Indole Alkaloids Isolated from Melodinus henryi Craib

Henrycinols A ( 1 ) and B ( 2 ), two novel indole alkaloids, together with three known compounds, (+)‐Δ¹⁴‐vincamine ( 3 ), (+)‐16‐epi‐Δ¹⁴‐vincamine ( 4 ), and (+)‐isoeburnamine ( 5 ), were isolated from the roots of Melodinus henryi Craib . Their structures were established on the basis of 1D‐ and 2D‐NMR spectroscopic analysis. The relative configuration of henrycinols A and B was determined by NOESY analysis.     

Two New Alkaloids from Daphniphyllum angustifolium Hutch.

Daphangustifolines A and B ( 1 and 2 ), two new Daphniphyllum alkaloids were isolated from the whole plant of Daphniphyllum angustifolium Hutch . Their structures were established on the basis of spectroscopic data. Their cytotoxicity against HL‐60, MCF‐7, and A549 cell lines was also evaluated.     

Novel sulfated sesterterpene alkaloids from the marine sponge Fasciospongia sp

Fasciospongines A (1) and B (2), two unusual sulfated sesterterpene alkaloids of an unprecedented structural class, have been isolated from the marine sponge Fasciospongia sp. The structures were elucidated on the basis of spectroscopic analysis. Compounds 1 and 2 displayed potent inhibitory activity to Streptomyces 85E in the hypha formation inhibition (HFI) bioassay.     

Paxdaphnidines A and B, novel penta- and tetracyclic alkaloids from Daphniphyllum paxianum

Two novel alkaloids, paxdaphnidine A (1) with a unique pentacyclic skeleton and paxdaphnidine B (2) with an uncommon tetracyclic skeleton, were isolated from the stems and leaves of Daphniphyllum paxianum. Their structures were established by spectral methods, especially two-dimensional NMR techniques ((1)H-(1)H COSY, HSQC, HMBC, and NOESY).     

Pseudoceratins A and B, antifungal bicyclic bromotyrosine-derived metabolites from the marine sponge Pseudoceratina purpurea

Pseudoceratins A (1) and B (2) have been isolated from the marine sponge Pseudoceratina purpurea. Pseudoceratins are unique among the large class of bromotyrosine-derived sponge metabolites with respect to the substitution pattern of aromatic rings and the presence of spiroacetal and oxime ether functional groups as well as an 1,5-diamino-1,5-dideoxy-D-arabitol tether. Pseudoceratins A (1) and B (2) are epimeric differing in the orientation of the tether. Their structures were determined by analysis of spectral data. The rigidity of the compounds arising from their bridged structure gave ROESY/NOESY spectra with many transannular cross-peaks, which allowed the assignment of the relative stereochemistry of 1 and 2 to be established. The d-configuration of the 1,5-diamino-1,5-dideoxyarabitol unit was determined by converting the fragment isolated from the acid hydrolysate to the Mosher's ester and compared the 1H NMR spectrum with those of standard samples. Pseudoceratins exhibited significant antifungal activity against Candida albicans.