Sinuscalide A: An Antiviral Norcembranoid with an 8/8-Fused Carbon Scaffold from the South China Sea Soft Coral Sinularia scabra.

Sinuscalide A (1), featuring an uncommon 8/8-fused carbon scaffold, three new norditerpenes, sinuscalides B-D (2-4), and sinuscatone A (5), with a 5/4/9 tricyclic carbon ring system, along with four known compounds were isolated from the South China Sea soft coral Sinularia scabra. The structures of the new compounds were established by extensive spectroscopic analysis, X-ray diffraction, and electronic circular dichroism (ECD). A plausible biosynthetic pathway for 1 was proposed. In a bioassay, compound 1 showed antiviral activity against human enterovirus EV71 (IC50 = 5.0 µM) and an inhibitory effect against RANKL-induced osteoclastogenesis (92.3% inhibition at 10 µM). Compound 5 exhibited mild inhibition against Streptococcus pneumoniae and Salmonella paratyph (MIC 16 µg/mL).

New alkylated benzoquinones from mangrove plant Aegiceras corniculatum with anticancer activity.

Three new alkylated benzoquinones, 2-hydroxy-5-ethoxy-3-nonyl-1,4-benzoquinone (1), 5-O-butyl-embelin (2), and 2,5-dihydroxy-6-methyl-3-pentadecyl-1,4-benzoquinone (3), together with seven known analogues (4-10), were isolated from the stems and twigs of mangrove plant, Aegiceras corniculatum. Their structural elucidation was achieved by spectroscopic methods, chemical exchanging experiments, and semisynthesis method. The cytotoxic activities of all the isolated compounds were evaluated by MTT assay. Compounds 1, 2, 8, 9, and 10 possess varying degrees of selective cytotoxicity against HL-60, HepG2, BGC-823, and A2780 cell lines.[Formula: see text].

Antioxidant xanthones and anthraquinones isolated from a marine-derived fungus Aspergillus versicolor.

Chemical examination of an EtOAc extract of cultured Aspergillus versicolor fungus from deep-sea sediments resulted in the isolation of four xanthones, eight anthraquinones and five alkaloids, including a new xanthone, oxisterigmatocystin D (1) and a new alkaloid, aspergillusine A (13). High resolution electron impact mass spectrometry (HR-EI-MS), FT-IR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds, and the absolute configuration of compound 1 was established by its NMR features and coupling constant. Furthermore, the biosynthesis pathway of these xanthones and anthraquinones were deduced, and their antioxidant activity and cytotoxicity in human cancer cell lines (HTC-8, Bel-7420, BGC-823, A549, and A2780) were evaluated. The trolox equivalent antioxidant capacity (TEAC) assay indicated most of the xanthones and anthraquinones possessing moderate antioxidant activities. The Nrf2-dependent luciferase reporter gene assay revealed that compounds 6, 7, 9, and 12 potentially activated the expression of Nrf2-regulated gene. In addition, compounds 5 and 11 showed weak cytotoxicity on A549 with the IC50 values of 25.97 and 25.60 µmol·L-1, respectively.

Four new minor brominated indole related alkaloids with antibacterial activities from Laurencia similis.

Four new minor brominated indole related alkaloids (one indoles, 1, one 1,3-dihydro-indole-2-one, 2, one carbazole, 3, and one 2-carbonylamino-benzoate, 4) were isolated and identified from Laurencia similis by extensive chromatographic and spectrometric methods. Among them, 1 and 2 were the first example of naturally occurring indole with 3-benzyl group and 1,3-dihydro-indole-2-one with 2-isopropylidene group, respectively, whereas 3 and 4 were the first carbazole alkaloids and 2-carbonylamino-benzoate, respectively, isolated from the genus Laurencia. Moreover, 1 showed the most potent antibacterial activity against seven bacterial strains with MIC values ranging from 2 to 8µg/mL.

Varioxiranols I-L, new lactones from a sponge-associated Emericella variecolor fungus.

Chemical examination of the sponge-associated fungus Emericella variecolor resulted in the isolation of four new lactones namely varioxiranols I-L(1-4)with different scaffolds, together with asteltoxin (5) and asteltoxin B (6). The structure elucidation of new compounds was accomplished by spectroscopic analysis, while the absolute configurations were determined by computed circular dichroism (ECD) and induced CD effects. Antitumor activities of these compounds were evaluated against different tumor cell lines, while the result indicated that the new compounds showed moderate cytotoxic activity against a panel of tumor cell lines.

New C13 lipids from the marine-derived fungus Trichoderma harzianum.

Chemical examination of the fermentation broth of a sponge-associated fungus Trichoderma harzinum HMS-15-3 led to the isolation of four pairs of new C13 lipid enantiomers namely harzianumols A-H (1a-4b). Their structures were elucidated on the basis of extensive spectroscopic (IR, MS, 1D, and 2D NMR) data analysis, including the modified Mosher's method for the assignment of their absolute configurations. The new compounds were evaluated for antihyperlipidemic effects in HepG2 cells.

Flavonoids from Stellaria nemorum and Stellaria holostea.

Stellaria nemorum L. and S. holostea L. (Caryophyllaceae) were investigated for their flavonoids. The new flavonoid 6-C-[(α-arabinopyranosyl)-( 1-->2)-O-ß- xylopyranosyl]apigenin (1) and the four known C-glycosides, 6-C-[(α-arabinopyranosyl)-(1-->2)-O-ß-glucopyranosyl]apigenin (2), apigenin 6-C-ß- galactopyranoside-8-C-ß-glucopyranoside (3), apigenin 6-C-ß-glucopyranoside-8-C-α-arabinopyranoside (4), and apigenin 6-C-ß-glucopyranoside-8-C-ß- xylopyranoside (5) were isolated from the aerial parts of S. nemorum for the first time. Furthemore, five known flavonoids, 3,5,7-trihydroxy-3',5'- dimethoxyflavone (9), diosmetin 6-C-ß-glucopyranoside (8), schaftoside (4), isoorientin (6) and orientin (7) were obtained from the aerial parts of S. holostea. Compounds 4, 8 and 9 are reported for the first time from this species. The structures of all isolated compounds were unambiguously elucidated by one- and two- dimensional NMR and mass spectral analysis, by acid hydrolysis, as well as by comparison with literature data. The crude extracts of the investigated species exhibited antimicrobial activity against Staphylococcus aureus, while none of the isolated compounds was found to be active.

Jaspiferins C-F, four new isomalabaricane-type triterpenoids from the South China Sea sponge Jaspisstellifera.

A chemical investigation of marine sponge Jaspis stellifera, collected from the South China Sea, led to the isolation of four new isomalabaricane-type triterpenoids, jaspiferins C-F (1-4). The structures of those compounds were elucidated by extensive spectroscopic methods. Jaspiferin C (1), which has the six-membered carbon ring at the side chain, was discovered for the first time from the isomalabaricane-type triterpenoids. The hypothesis of a biogenetic pathway to generate jaspiferin C (1) was depicted.

Pharmacokinetics and tissue distribution of furanodiene W/O/W multiple emulsions in rats by a fast and sensitive HPLC-APCI-MS/MS method.

A sensitive and specific HPLC-APCI-MS/MS method was developed and validated for the quantification of furanodiene, a natural antitumor compound in rat plasma and tissues. W/O/W multiple emulsions of furanodiene, identified through microscope-observation and eosin staining method, were prepared with a two-step-procedure. Pharmacokinetics and tissue distribution were studied in rats after oral, intraperitoneal and intravenous injection with the dose of 5, 10 and 50 mg/kg, respectively. The assay achieved a good sensitivity and specificity for the determination of furanodiene in biological samples. The results showed that the concentration-time curves of furanodiene in rats after intravenous injection were fitted to a two-compartment model and the linear pharmacokinetic characteristic. The highest concentration in rat tissue was observed in the spleen, followed by heart, liver, lung, kidney, small intestine and brain. Comparing with the low concentration in plasma, furanodiene could be detected in various tissue samples after oral or intraperitoneal injection which indicated furanodiene had good and rapid tissue uptake. The results suggested that the wide tissue distribution of furanodiene could conduce to the therapeutic effects, but the short biological half-life limited its further application as an antitumor agent. The results are helpful for the structure modification of furanodiene as an antitumor candidate.

Kandenols A-E, eudesmenes from an endophytic Streptomyces sp. of the mangrove tree Kandelia candel.

Five novel eudesmene-type sesquiterpenes, kandenols A-E (1-5), have been isolated from Streptomyces sp. HKI0595 derived from the mangrove plant Kandelia candel. Their structures were established through NMR and mass spectrometry, and absolute configurations were established by the Mosher method and comparison of CD spectra with α-rotunol and ß-rotunol. The kandenols are reminiscent of various plant-derived eudesmenes, yet kandenols B and C are unusual because of their hydroperoxide moieties. Kandenol E is the first bacterial agarofuran, which belongs to an important group of antibiotics. Whereas the kandenols display no cytotoxicity against 12 human cell lines, weak to moderate antimicrobial activities were detected against Bacillus subtilis ATCC 6633 and Mycobacterium vaccae IMET 10670.

Identification and characterization of an anti-fibrotic benzopyran compound isolated from mangrove-derived Streptomyces xiamenensis.

An anti-fibrotic compound produced by Streptomycesn xiamenensis, found in mangrove sediments, was investigated for possible therapeutic effects against fibrosis. The compound, N-[[3,4-dihydro-3S-hydroxy-2S-methyl-2-(4'R-methyl-3'S-pentenyl)-2H-1-benzopyran-6-yl]carbonyl]-threonine (1), was isolated from crude extracts and its structure, including the absolute configuration was determined by extensive spectroscopic data analyses, Mosher's method, Marfey's reagent and quantum mechanical calculations. In terms of biological effects, this compound inhibits the proliferation of human lung fibroblasts (WI26), blocks adhesion of human acute monocytic leukemia cells (THP-1) to a monolayer of WI26 cells, and reduces the contractile capacity of WI26 cells in three-dimensional free-floating collagen gels. Altogether, these data indicate that we have identified a bioactive alkaloid (1) with multiple inhibitory biological effects on lung excessive fibrotic characteristics, that are likely involved in fibrosis, suggesting that this molecule might indeed have therapeutic potential against fibrosis.

Structure-activity relationship of halophenols as a new class of protein tyrosine kinase inhibitors.

A series of new benzophenone and diphenylmethane halophenol derivatives were prepared. Their structures were established based on (1)H NMR, (13)C NMR and HRMS data. All prepared compounds were screened for their in vitro protein tyrosine kinase (PTK) inhibitory activities. The effects of modification of the linker, functional groups and substituted positions at the phenyl ring on PTK inhibitory activity were investigated. Twelve halophenols showed significant PTK inhibitory activity. Among them, compounds 6c, 6d, 7d, 9d, 10d, 11d and 13d exhibited stronger activities than that of genistein, the positive reference compound. The results gave a relatively full and definite description of the structure-activity relationship and provided a foundation for further design and structure optimization of the halophenols.

Pestalotiopamide E, a new amide from the endophytic fungus Pestalotiopsis sp.

Chemical examination of the endophytic fungus Pestalotiopsis sp., isolated from the leaves of the Chinese mangrove Rhizophora mucronata, yielded a new amide called pestalotiopamide E (1). The structure of the new compound was unambiguously elucidated on the basis of extensive spectroscopic data analysis.

A family of multicyclic indolosesquiterpenes from a bacterial endophyte.

Three novel indolosesquiterpenes, xiamycin B (1b), indosespene (2), and sespenine (3), along with the known xiamycin A (1a) were isolated from the culture broth of Streptomyces sp. HKI0595, a bacterial endophyte of the widespread mangrove tree Kandelia candel. Agar diffusion assays revealed moderate to strong antimicrobial activities against several bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis, while no cytotoxicity against human tumor cell lines was observed. Together with the previously reported oridamycin, the endophyte metabolites represent the first indolosesquiterpenes isolated from prokaryotes.

Xiamycin, a pentacyclic indolosesquiterpene with selective anti-HIV activity from a bacterial mangrove endophyte.

A novel pentacyclic indolosesquiterpene, named xiamycin (1), and its methyl ester (2) have been obtained from Streptomyces sp. GT2002/1503, an endophyte from the mangrove plant Bruguiera gymnorrhiza. The structures were established by 1D and 2D NMR, MS, and X-ray crystallography, and the absolute configuration of 1 was elucidated by the modified Mosher method. Compound 1 exhibits selective anti-HIV activity; it specifically blocks R5 but has no effects on X4 tropic HIV-1 infection. In a panel of cytotoxicity assays, compound 2 showed to be more potent (geometric mean IC(50)=10.13 µM) compared to compound 1 (geometric mean IC(50) >30 µM), with antitumor potency being generally less pronounced. Xiamycin represents one of the first examples of indolosesquiterpenes isolated from prokaryotes.

Phenolic compounds and their anti-oxidative properties and protein kinase inhibition from the Chinese mangrove plant Laguncularia racemosa.

Phenolic compounds, named integracin D (1), (7'R, 8'S, 8S)-8-hydroxyisoguaiacin (3), (2R, 3R) pinobanksin-3-caffeoylate (5) and threo-8S-7-methoxysyringylglycerol (6), respectively, were isolated from the Chinese mangrove plant Laguncularia racemosa (L) Gaertn. f. (Combretaceae), together with 23 known phenolic metabolites. Their structures were elucidated on the basis of extensive spectroscopic analyses including that of IR, UV, MS, CD, 1D and 2D NMR spectra as well as by comparison with literature data. Compound 5 showed significant anti-oxidative activity in the DPPH and TEAC free-radical-scavenging assays, while several of the phenolic compounds were tested for protein kinase inhibitory activity in an assay involving 24 different human tumor related protein kinases. Compounds 5, 7, and 23 showed potential inhibition with IC(50) values between 2.2 and 3.6microg/mL toward individual kinases. The ellagic acid derivatives were tested for insecticidal activity.

[Effects of cembrane-type diterpenes on proliferation of PC12 cells and their antagonistic effects on neurotoxicity induced by glutamate].

OBJECTIVE: To investigate the effects of cembrane-type diterpenes extracted from Sinularia flexibilis on the proliferation of PC12 cells and their protective effects on PC12 cells exposed to glutamate. METHODS: Methyl thiazolyl tetrazolium (MTT) method was adopted to observe the effects of cembrane-type diterpenes (compound 1, compound 2 and compound 3) on the proliferation of PC12 cells. And the protective effects of the three compounds on PC12 cells exposed to glutamate were also detected by MTT. Furthermore, the influence of compound 1 on intracellular concentration of calcium in PC12 cells exposed to glutamate was detected by laser confocal microscopy. RESULTS: After 72-hour PC12 cell culture, OD values in the 2, 10 and 50 micromol/L compound 1 groups were significantly higher than that in the normal group (P<0.05, P<0.01). After 24-hour glutamate damage, OD values in the 0.4, 2 and 50 micromol/L compound 1 groups, the 0.4, 2 and 100 micromol/L compound 2 groups and the 2 micromol/L compound 3 group were obviously increased as compared with the untreated group (P<0.01, P<0.05). After 48-hour glutamate damage, OD values in the compound 1 group were approximate to those in the normal control and the positive control group while were significantly higher than that in the untreated group (P<0.01, P<0.05), but no dose-dependent effect was observed. Compound 1 of 0.4, 2, 50 micromol/L could significantly reduce the intracellular concentration of calcium in PC12 cells exposed to glutamate (P<0.05, P<0.01), which was also approximate to the effect of nimodipine (positive control drug). CONCLUSION: Cembrane-type diterpenes (compound 1, compound 2 and compound 3) extracted from Sinularia flexibilis have obvious protective effects on PC12 cells damaged by glutamate, and compound 1 has the best neuroprotective effect. The mechanism of the neuroprotective effect of compound 1 may lie in reducing the intracellular concentration of calcium in PC12 cells exposed to glutamate and relieving the calcium overload.

[Isolation and identification of compounds from marine mangrove plant Avicennia marina].

OBJECTIVE: To investigate the chemical constituents from Avicennia marina. METHODS: The isolation and purification of the CH2Cl2 and n-BuOH fractions of this plant were performed, and the chemical structures were elucidated by spectral analysis as well as comparison of their spectral data with literature values. RESULTS: Three novel compounds were obtained and identified as erythro-guaiacylglycerol-beta-ferulic acid ether (1), marinnone A (16) and marinnone B (17), along with eighteen known compounds as threo-guaiacylglycerol-beta-ferulic acid ether (2), eleutheroside E2 (3), (+)-lirioresinol A (4), dihydroxymethyl-bis (3, 5-dimethoxy-4-hydroxyphenyl) tetrahydrofuran-9-O-beta-glucopyranoside (5), (+)-lyoniresinol 3a-O-beta-D-glucopyranoside (6), (-)-lyoniresinol 3a-O-beta-D-glucopyranoside (7), epi-pinoresinol (8), leucoseceptoside A (9), jionoside C (10), salsaside A (11), ilicifolioside A (12), acteoside (13), isoacteoside (14), ethyl ferulate (15), avicennone D (18), avicenone E (19), avicennol C (20), and stenocarpoquinone B (21). CONCLUSION: Three new compounds (1, 16 and 17) were obtained and thirteen known compounds, 2-12, 14 and 15 were isolated from Avicennia genus for the first time.

Bioactive metabolites from the endophytic fungus Stemphylium globuliferum isolated from Mentha pulegium.

The endophytic fungus Stemphylium globuliferum was isolated from stem tissues of the Moroccan medicinal plant Mentha pulegium. Extracts of the fungus, which was grown on solid rice medium, exhibited considerable cytotoxicity when tested in vitro against L5178Y cells. Chemical investigation yielded five new secondary metabolites, alterporriol G (4) and its atropisomer alterporriol H (5), altersolanol K (11), altersolanol L (12), stemphypyrone (13), and the known compounds 6-O-methylalaternin (1), macrosporin (2), altersolanol A (3), alterporriol E (6), alterporriol D (7), alterporriol A (8), alterporriol B (9), and altersolanol J (10). The structures were determined on the basis of one- and two-dimensional NMR spectroscopy and mass spectrometry. Among the alterporriol-type anthranoid dimers, the mixture of alterporriols G and H (4/5) exhibited considerable cytotoxicity against L5178Y cells with an EC(50) value of 2.7 microg/mL, whereas the other congeners showed only modest activity. The compounds were also tested for kinase inhibitory activity in an assay involving 24 different kinases. Compounds 1, 2, 3, and the mixture of 4 and 5 were the most potent inhibitors, displaying EC(50) values between 0.64 and 1.4 microg/mL toward individual kinases.