Two unusual novel bicyclic lactones, suberosanones A and B (1 and 2, resp.), characterized by the co-occurrence of cyclopentenone and butanolide rings within the same molecule, along with one tricyclic cyclopentenone derivative, suberosanone C (3), were isolated from the South China Sea gorgonian coral Subergorgia suberosa. Their structures were unambiguously established by detailed spectroscopic analyses (NMR, IR, and HR-MS). The absolute configurations of 1 and 2 were determined by quantum-chemical calculations using the time-dependent density-functional theory (TDDFT) method. All compounds showed neither antifouling activity against Balanus amphitrite larvae settlement nor antibacterial activity against a panel of bacterial strains at concentrations up to 25 μg/ml.

The reaction of pyridine-2,3-dicarboxylic acid (2,3-pydcH₂) with CuI and Ln₂O₃ under hydrothermal conditions generated a series of new one-, two-, and three-dimensional coordination polymers, namely, {[Cu₃Ln₂(2,3-pydc)₆(H₂O)₁₂]·12H₂O}_n [Ln = La(1), Nd(2)], {[Cu₃Ln₂(2,3-pydc)₆(H₂O)₈]·6H₂O}_n [Ln = Sm(3), Gd(4)], and {[Cu₃Ln₂(2,3-pydc)₆(H₂O)₁₀]·10H₂O}_n [Ln = Tb(5), Ho(6), Er(7), Yb(8), Lu(9)]. The results show that compounds 1 and 2 (type I structure) are 1-D Cu-4f rhombic lattice chains that are formed through assembly of two building block units Cu₃(pydc)₆ and Ln(H₂O)₆. Compounds 3–4 (type II structure) are 2-D layers that are constructed from building block units [Cu(pydc)₂(H₂O)₂] μ₂-bridging adjacent 1-D rhombic lattice chains –[(Cu₂(pydc)₄)-(La(H₂O)₄)]_n–. Complexes 5–9 (type III structure) are also isomorphous and have the same 3-D network structures with 1-D channels along the c axis, and are formed by assembly of building block units Cu₃(pydc)₆ with Ln(H₂O)₅. The progressive structural variation from the 1-D chains 1–2 to 2-D layers 3–4 and to 3-D frameworks 5–9 is attributed to the lanthanide contraction effect and to the different coordination modes of 2,3-pydc^2–. The N₂ gas adsorption and fluorescent properties of the partial complexes were also investigated.

Two new pentahydroxylated steroids, (3β,12β,16β,23E)-cholesta-5,23-diene-3,12,16,20,25-pentaol (1) and (3β,12β,16β)-cholesta-5,25(26)-diene-3,12,16,20,24-pentaol (2), were isolated from the EtOH extract of the South China Sea gorgonian Subergorgia suberosa. In addition, four known steroids were detected. The structures of these compounds were established by spectroscopic methods and comparison of their data with those of the related known compounds. In addition, the cyctotoxicities of the compounds were evaluated against selected cancer cell lines.

Two new steroids, named 4α,22-dimethyl-Cholest-22-en-3β-ol (1) and 4α-methyl-Cholest-7,22-dien-3β-ol (2), along with two known steroids, were isolated from the soft coral Sinularia brassica. The structures of the new compounds were determined on the basis of extensive spectroscopic data (MS, ¹H and ¹³C NMR, ¹H¹H COSY, ¹³C¹H COSY, HMBC and NOESY) analysis. Copyright © 2010 John Wiley & Sons, Ltd.

Background and purpose:  Many bromopyrrole compounds have been reported to have in vitro antineoplastic activity. In a previous study, we isolated N-(4, 5-dibromo-pyrrole-2-carbonyl)-L-amino isovaleric acid methyl ester (B6) from marine sponges. Here, we investigated the in vitro and in vivo antineoplastic activity of B6 and its potential mechanism.

Experimental approach:  The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the in vitro antineoplastic activity of B6. Flow cytometry, western blot analysis and morphological observations were used to investigate its mechanism of action. A mouse xenograft model was used to determine its in vivo activity.

Key results:  B6 inhibited the proliferation of various human cancer cells in vitro, with highest activity on LOVO and HeLa cells. B6 also exhibited significant growth inhibitory effects in vivo in a xenograft mouse model. Acute toxicity analysis suggested that B6 has low toxicity. B6-treated cells arrested in the G1 phase of the cell cycle and had an increased fraction of sub-G1 cells. In addition, the population of Annexin V-positive/propidium iodide-negative cells increased, indicating the induction of early apoptosis. Indeed, B6-treated cells exhibited morphologies typical of cells undergoing apoptosis. Western blotting showed cleaved forms of caspase-9 and caspase-3 in cells exposed to B6. Moreover, B6-promoted Ca²⁺ release and apoptosis was associated with elevated intracellular Ca²⁺concentration.

Conclusions and implications:  B6 has significant antineoplastic activity in vitro as well as in vivo. It inhibits tumour cell proliferation by arresting the cell cycle and inducing apoptosis. With its low toxicity, B6 represents a promising antineoplastic, primary compound.

Two new steroids isolated from EtOH extracts of the South China Sea soft coral Chromonephthea sp. were identified. One-dimensional (1D) and two-dimensional (2D) NMR experiments including COSY, HSQC, HMBC and NOESY were used for the determination of their structure. Copyright © 2008 John Wiley & Sons, Ltd.