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A detailed chemical investigation of two South China Sea nudibranchs Phyllidiella pustulosa and Phyllidia coelestis, as well as their possible sponge-prey Acanthella cavernosa, led to the isolation of one new nitrogenous cadinane-type sesquiterpenoid xidaoisocyanate A (1), one new naturally occurring nitrogen-containing kalihinane-type diterpenoid bisformamidokalihinol A (16), along with 17 known nitrogenous terpenoids (2&ndash, 15, 17&ndash, 19). The structures of all the isolates were elucidated by detailed spectroscopic analysis and by the comparison of their spectroscopic data with those reported in the literature. In addition, the absolute stereochemistry of the previously reported axiriabiline A (5) was determined by X-ray diffraction (XRD) analysis. In a bioassay, the bisabolane-type sesquiterpenoids 8, 10, and 11 exhibited cytotoxicity against several human cancer cell lines.

A detailed chemical investigation of two South China Sea nudibranchs Phyllidiella pustulosa and Phyllidia coelestis, as well as their possible sponge-prey Acanthella cavernosa, led to the isolation of one new nitrogenous cadinane-type sesquiterpenoid xidaoisocyanate A (1), one new naturally occurring nitrogen-containing kalihinane-type diterpenoid bisformamidokalihinol A (16), along with 17 known nitrogenous terpenoids (2–15, 17–19). The structures of all the isolates were elucidated by detailed spectroscopic analysis and by the comparison of their spectroscopic data with those reported in the literature. In addition, the absolute stereochemistry of the previously reported axiriabiline A (5) was determined by X-ray diffraction (XRD) analysis. In a bioassay, the bisabolane-type sesquiterpenoids 8, 10, and 11 exhibited cytotoxicity against several human cancer cell lines.

The first total synthesis of xestospongenyne, a marine brominated polyunsaturated lipid with remarkable pancreatic lipase inhibitory activity (IC50 = 0.61 μM), was achieved from commercially available hept-6-yn-1-ol with 13% overall yield. This synthesis will permit further biological study of xestospongenyne and its analogues, with the aim of producing an antiobesity drug.

One new polycyclic furanobutenolide-derived norcembranoid, xiguscabrolide H (1), together with eleven known related norditerpenoids 2-12 were isolated from South China Sea soft corals Sinularia scabra and S. polydactyla, respectively. Among them, compounds 1, 6, 8, and 12 were discovered from the former species, while compounds 2-5, 7, and 9-11 were obtained from the latter species. The structure of new compound 1 was elucidated by extensive spectroscopic analysis and by the comparison with the reported data. With the assistance of time-dependent density functional theory electronic circular dichroism (TDDFT-ECD) calculations, its absolute configuration was determined. Moreover, the absolute stereostructures of the known compounds 3, 4, and 9-12, of which only relative configurations were assigned, were established for the first time by X-Ray diffraction analysis and TDDFT-ECD calculations, respectively. In bioassay, several isolates exhibited potent inhibitory effects on the ConA-induced T lymphocytes and/or LPS-induced B lymphocytes proliferation.

A new steroidal ketone (1), with an ergosta-22,25-diene side chain, was obtained from the South China Sea marine sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of detailed spectroscopic analysis and by comparison with literature. Compound 1 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 4.27 ± 0.55 μM, which is comparable with the positive control oleanolic acid (IC50 = 2.63 ± 0.22 μM).

Four known (1-4) and two new (5 and 6) lysophospholipids were isolated from the sponge Spirastrella purpurea from Weizhou Island, Guangxi Autonomous Region, China. The structures of the new compounds (5 and 6) were elucidated by detailed spectroscopic techniques, including 1D and 2D NMR ((1)H and (13)C NMR, (1)H-(1)H COSY, HSQC, and HMBC) as well as mass spectrometry and optical rotation experiments. The known compounds (1-4) were identified by comparison of their spectroscopic data and specific optical rotation with those reported in the literature. The isolated compounds displayed various moderate in vitro antifungal activities against four fungi (Cryptococcus neoformans, Candida glabrata, Trichophyton rubrum, and Aspergillus fumigatus), whereas they displayed no neuroprotective activity against Aβ25-35-induced SH-SY5Y cell damage.

Three new capnosane type diterpenoids, sarcophytrols A–C (1–3), were isolated from the South China Sea soft coral Sarcophyton trocheliophorum. Among them, 1 and 2 share a dodecahydrocyclopenta[6,7]cycloundeca[1,2-b]oxirene ring system with an unusual 1Z-configuration, whereas 1 and 3 encompass a peculiar isopropyl alcohol moiety. Their structures were elucidated by extensive spectroscopic analysis and the absolute configuration of 1 was determined by an X-ray diffraction analysis with Cu Kα radiation on a single crystal.

Two additional new members of the onchidione family, 16-epi-onchidione (1) and 4-epi-onchidione (2), co-occurring with six previously reported bis-gamma-pyrone polypropionates including onchidione (3), were isolated from the marine pulmonate Onchidium sp. Their structures were determined by extensive spectroscopic analysis and by comparison with 3 and onchidione-related derivatives. The absolute configuration of 1 was established by X-ray diffraction analysis employing graphite monochromated Cu K-alpha radiation (lambda = 0.71073 angstrom) with small Flack parameter 0.08. In addition, the absolute stereochemistry of previously reported onchidionol (6) was confirmed by the X-ray diffraction analysis. Some of the isolated compounds showed significant activation effects on the splicing of XBP1 mRNA as ER stress modulators to inhibit the growth of tumors. (C) 2018 Elsevier Ltd. All rights reserved.

Ten stigmastane-type steroids bearing unusual Δ

In the present study, two new trinor-guaiane sesquiterpenes, named clavuridins B (1), and A (2), along with three known sesquiterpenes (3-5), were isolated from the Xisha soft coral Clavularia viridis. Their structures and absolute configurations were determined on the basis of spectroscopic analysis, X-ray diffraction analysis with Cu Kα radiation and by comparison with related model compounds. Compounds 1 and 3-5 were evaluated for their cytotoxic activity.

Minor metabolic components, six new cembranoids sarcophytrols G – L (1 – 6) along with two known related analogues 7 and 8, were isolated from the South China Sea soft coral Sarcophyton trocheliophorum. Their structures were elucidated by extensive spectroscopic analyses (1D- and 2D-NMR, and ESI-MS.) as well as comparison with literature data. As part of our ongoing research project for discovering bioactive substances from Chinese marine invertebrates, compounds 1 – 8 were tested for their inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of Type-II diabetes and obesity. However, none of them exhibited potent PTP1B inhibitory activities. This article is protected by copyright. All rights reserved.

Eleven highly halogenated chamigrane sesquiterpenoids, compositacins A–K, including one unusual rearranged chamigrane sesquiterpenoid, compositacin A, were isolated from the red alga Laurencia composita Yamada, along with seven known structural analogues. Compositacins B and D are the first examples of chamigranes bearing an ether bridge involving C-5/C-9 and C-3/C-5, respectively, while compositacins B and C represent the first chamigranes with a C-10 carbonyl group. Their structures were elucidated on the basis of extensive spectroscopic analysis. The absolute configuration of compositacin B was determined by ECD calculation, whereas the absolute configurations of compositacins A and C–L were proposed on biosynthetic grounds by comparison to compositacin B and the related known sesquiterpenoids johnstonol and yicterpene A. We also suggest that the structure of the previously reported sesquiterpenoid laurokamin A should be revised. Cytotoxicity and antifungal activity of these isolates were also investigated. The results showed that compositacin G exhibited good antifungal activity against Microsporum gypseum (Cmccfmza) with a MIC80 value of 4 μg/mL relative to positive controls. Four of the chamigrane halosesquiterpenoids showed marginal cytotoxicity against the A-549 human lung adenocarcinoma cell line with IC50 values ranging from 48.6 to 85.2 μM.

A new sterol, named thunberol (1), along with four known analogs, 24-ethylcholesta-4,24(28)-dien-3-one (2), stigmasta-5,28-dien-3β-ol (3), cholesta-5,14-dien-3β-ol (4), and cholesta-5,23-dien-3β,25-diol (5), were isolated from the brown alga Sargassum thunbergii collected from East China Sea. The structures of these metabolites were elucidated on the basis of detailed spectroscopic analysis and by comparison with the literature data. Thunberol (1) exhibited significant inhibitory activity against protein tyrosine phosphatase 1B, a potential drug target for the treatment of Type-II diabetes and obesity, with an IC50 value of 2.24 μg/ml.

A detailed chemical investigation of the Chinese soft coral Cladiella krempfi has yielded four new eunicellin-based diterpenoids along with five known compounds. The stereostructures of the new metabolites have been elucidated by extensive spectroscopic analysis, mainly based on 2D NMR spectroscopy, and by chemical transformations. A remarkable variation in the diterpene composition in dependence of the exact site of collection was observed. Some of the isolated diterpenoids were shown to exhibit antiproliferative activity against C6 glioma cells, multi-drug resistant tumor cell line.

Eight new tetranortriterpenoids (1–8) were isolated from the twigs and leaves of the Chinese mangrove plant Xylocarpus granatum, together with four related known ones (9–12). The structures of new compounds were elucidated by detailed spectroscopic analysis. The absolute configuration of 9-epixylogranatin A (1) was determined by time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculations of the solution conformers. Xylogranatumin A (2) represents the first example of the 9, 10-seco limonoid with an unprecedented oxygen-bridged B ring (2,7-dioxabicyclo[2.2.1]-heptane). All the isolates were evaluated for the in vitro neuroprotective activity, both compounds 11 and 12 displayed moderate effects against H2O2-induced neurotoxicity in PC12 cells at the concentration of 10 μM, with an increase in cell viability of 12.0% and 11.6%, respectively.

Two new cembranoids, yalongenes A (1) and B (2), were isolated from the South China Sea soft coral Sarcophyton trocheliophorumMarenzeller. Their structures were elucidated by detailed spectroscopic analysis (IR, MS, and NMR) and by comparison with a related model compound. Yalongenes 1 and 2 were evaluated for their cytoprotective effects on SH-SY5Y cell injury induced by H2O2in vitro, and the result showed that only compound 1 had a significant cytoprotective activity at the concentration of 1 μM.

The absolute configurations of onchidione (1), previously reported from the marine pulmonate Onchidium sp., and the related alcohols onchidiol (2) and 4-epi-onchidiol (3), first described as methanolysis products of 1, were assigned by X-ray diffraction analysis and solid-state time-dependent density functional theory electronic circular dichroism. Alcohol 3 was incorrectly reported as the C-16 epimer of 2.

Two new uncommon polyunsaturated amino ketones, (6Z,9Z,12Z,15Z)-1-[(2-phenylethyl)amino]octadeca-6,9,12,15-tetraen-3-one (1) and (6Z,9Z,12Z,15Z)-1-(diethylamino)octadeca-6,9,12,15-tetraen-3-one (2), were isolated from the Gangxi sponge Haliclona sp. The structures of new compounds 1 and 2 were determined by detailed analysis of their 1D- and 2D-NMR spectra, and high-resolution mass spectrometry.

A new kalihinol diterpene, 10-epi-kalihinol X (1), together with two known related diterpenes (2 and 3), and two sesquiterpenes (4 and 5) were isolated from the Hainan sponge Acanthella sp. The structure of the new compound was elucidated on the basis of the detailed analysis of its spectroscopic data and by comparison of its NMR data with those of structurally related compounds. Compounds 1 and 3-5 exhibited in vitro moderate cytotoxicities against human lung adenocarcinoma cell line A549, with IC50 values of 9.30, 3.17, 2.44, and 1.98 microg/mL, respectively.

Three new capnosane type diterpenoids, sarcophytrols A–C (1–3), were isolated from the South China Sea soft coral Sarcophyton trocheliophorum. Among them, 1 and 2 share a dodecahydrocyclopenta[6,7]cycloundeca[1,2-b]oxirene ring system with an unusual 1Z-configuration, whereas 1 and 3 encompass a peculiar isopropyl alcohol moiety. Their structures were elucidated by extensive spectroscopic analysis and the absolute configuration of 1 was determined by an X-ray diffraction analysis with Cu Kα radiation on a single crystal.

A new 9,11-secosteroid, 25(26)-dehydrosarcomilasterol (1), two new polyhydroxylated steroids, 7α-hydroxy-crassarosterol A (2) and 11-acetoxy-7α-hydroxy-crassarosterol A (3), together with three known related ones (4-6), were isolated from the South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis, respectively. The structures of the new steroids were elucidated on the basis of extensive spectroscopic analyses, comparison with the literature data and chemical correlation. Compound 2 exhibited a moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with an IC50 value of 33.05μM. Compounds 1-3 showed weak in vitro cytotoxicities against the tumor cell lines K562 and HL-60.

Four new diterpenoids (I-III) have been isolated together with five already known, structurally related diterpenoids.

Two new prenylated para-xylenes, named caulerprenylols A (1) and B (2), were isolated from the green alga Caulerpa racemosa, collected from the Zhanjiang coastline, China. The structures of the two metabolites were elucidated on the basis of detailed spectroscopic analysis. This is the first report of prenylated para-xylenes from marine algae and from marine organisms as well. Moreover, caulerprenylol B (2) is also characterized by an uncommon indane ring system. In in vitro bioassays, the new compounds exhibited a broad spectrum of antifungal activity against Candida glabrata (537), Trichophyton rubrum (Cmccftla), and Cryptococcus neoformans (32609) with MIC80 values between 4 and 64 μg/mL when compared to amphotericin B (MIC80 values of 2.0, 1.0, and 4.0 μg/mL, respectively) as a positive control and showed no growth inhibition activity against the tumor cells HL60 and A549.

The stereoselective synthesis of methyl spongoate, a naturally occurring new steroid derivative with an unusual C-20 methoxycarbonyl group and potent antitumor activities, was achieved starting from the commercially available pregnenolone acetate in 11% overall yield.

Aims: The aim of this study is to develop an RT-PCR assay combined with immunomagnetic beads (IMS/RT-PCR) coating monoclonal antibody (Mab) for separation and detection of norovirus (genogroup II) in faecal samples. We furthermore compare its detection limits with IMS/RT-PCR using polyclonal antibody (Pab) and the TRIzol extraction method followed by RT-PCR (TRIzol-RT-PCR). Methods and Results: Mab-coated beads and Pab-coated beads were added to a series of tenfold dilutions of faecal extract containing norovirus in 1 ml PBS. After incubation and collection, the RNA was released by heating from virus separated by beads. The tenfold dilutions of faecal were also extracted with TRIzol reagent. The RNA was used as the template for RT-PCR detection (primers: JV12–JV13). IMS/RT-PCR using Mab showed an endpoint in the 10−7 dilution and was 102 times more sensitive than IMS/RT-PCR using Pab and was at least 103 times more sensitive than TRIzol-RT-PCR method. Conclusions: IMS/RT-PCR using Mab proved to be a more sensitive method of noroviruses (NVs) detection than IMS/RT-PCR using Pab and the TRIzol-RT-PCR method. Significance and Impact of the Study: This is the first study to detect NVs with IMS/RT-PCR using Mab, and could serve as a model for future assays when broadly reactive NVs-specific Mabs are developed.

[reaction: see text] The total synthesis of gymnorrhizol, a naturally occurring macrocyclic polydisulfide with a new skeleton and a potent proteintyrosinephosphatase 1B inhibitor, was prepared in three steps, starting from (R)-1-bromo-3-chloroisopropanol and 1,3-dichloropropan-2-ol.