Determination of C-23 configuration in (20R)-23-hydroxycholestane side chain of steroid compounds by 1H and 13C NMR spectroscopy

Epimeric (20R,23R)- and (20R,23S)-23-hydroxycholestane steroids were synthesized. Their structures were elucidated by extensive 1H and 13C NMR spectroscopy and application of the Mosher's method. All proton and carbon signals of the side chains were assigned. Based on these assignments spectral data allow the determination of the C-23 stereochemistry of (20R)-23-hydroxycholestane side chains of the new natural steroids by comparison with spectra of the obtained model compounds. As a result, the C-23 configuration of two steroid compounds from the starfishes Lethasterias nanimensis chelifera and Lethasterias fusca was established.

Determination of C-23 Configuration in (20R)-23-Hydroxycholestane Side Chain of Steroid Compounds by 1H and 13C NMR Spectroscopy

Epimeric (20 R,23 R)- and (20 R,23 S)-23-hydroxycholestane steroids were synthesized. Their structures were elucidated by extensive 1H and 13C NMR spectroscopy and application of the Mosher's method. All proton and carbon signals of the side chains were assigned. Based on these assignments spectral data allow the determination of the C-23 stereochemistry of (20 R)-23-hydroxycholestane side chains of the new natural steroids by comparison with spectra of the obtained model compounds. As a result, the C-23 configuration of two steroid compounds from the starfishes Lethasterias nanimensis chelifera and Lethasterias fusca was established.

The anticancer activity of 3- and 10-bromofascaplysins is mediated by caspase-8, -9, -3-dependent apoptosis

3- and 10-Bromofascaplysins was previously found to possess cytotoxic activity. In this study, we investigated their cancer preventive and proapoptotic properties. These effects were tested on mouse skin epidermal JB6 P(+) Cl41 cell line, its stable transfectants, and human tumor HL-60, THP-1, SNU-C4, SK-MEL-28, DLD-1, MDA-MB-231, and HeLa cells using a variety of assessments, including a cell viability (MTS) assay, flow cytometry, anchorage-independent soft agar assay, luciferase assay, mitochondrial permeability assay, and Western blotting. 3- and 10-Bromofascaplysins were effective at submicromolar concentrations as the anticancer agents, which exerted their action, at least in part, through the induction of caspase-8, -9, -3-dependent apoptosis.

Aaptamine Alkaloids from the Vietnamese Sponge Aaptos sp

A series of aaptamines, including one new alkaloid (1), were isolated from the marine sponge Aaptos sp. collected in Vietnamese waters. The structure of 1 was elucidated using NMR and HRESIMS, as well as by chemical transformation of 1 to the previously known aaptamine and established as 3-N-morpholinyl-9-demethyl(oxy)aaptamine. The isolated compounds showed a potential cancer preventive activity.

Aaptamine alkaloids from the Vietnamese sponge Aaptos sp

A series of aaptamines, including one new alkaloid (1), were isolated from the marine sponge Aaptos sp. collected in Vietnamese waters. The structure of 1 was elucidated using NMR and HRESIMS, as well as by chemical transformation of 1 to the previously known aaptamine and established as 3-N-morpholinyl-9-demethyl(oxy)aaptamine. The isolated compounds showed a potential cancer preventive activity.

Anticancer activity of 3-demethylubiquinone Q2. In vivo experiments and probable mechanism of action

BACKGROUND

3-Demethylubiquinone Q2 (3DMUbQ2), isolated from the ascidian Aplidium glabrum and later synthesized, is known as a natural product inhibiting EGF-induced malignant JB6 P+ Cl 41 cell transformation. However, its in vivo anticancer properties and probable mechanism of this action have not been studied.

MATERIALS AND METHODS

Preventive and curable effects of3DMUbQ2 on mice with inoculated Ehrlich carcinoma tumors were examined by magnetic resonance tomography. Capability to inhibit human tumor cell colony growth and induce their apoptosis was investigated using the anchorage-independent phenotype expression assay in soft agar and flow cytometry.

RESULTS

3DMUbQ2 inhibits the growth of the solid Ehrlich carcinoma in mice, especially using the prophylactic scheme of administration (50% inhibition). It inhibits the phenotype expression of HT-460, HCT-116 and SK-MEL-28 human tumor cells and induces apoptosis of these cell lines, as well as that of HL-60 and THP-1 tumor cells.

CONCLUSION

3DMUbQ2 and other related marine polyprenylquinones have potential for development of a new antitumor agent in cancer prophylactics and treatment and should be further investigated.

Evaluation of cancer-preventive activity and structure-activity relationships of 3-demethylubiquinone Q2, isolated from the ascidian Aplidium glabrum, and its synthetic analogs

PURPOSE

3-Demethylubiquinone Q2 was isolated from the ascidian Aplidium glabrum. The cancer-preventive properties and the structure-activity relationship for 3-demethylubiquinone Q2 and 12 of its synthetic analogs are reported.

METHODS

Compounds, having one or several di- or triprenyl substitutions and quinone moieties with methoxyls in different positions, were synthesized. The cancer-preventive properties of compounds and were tested in JB6 Cl41 mouse skin cells, using a variety of assessments, including the methanethiosulfonate (MTS) assay, flow cytometry, and soft agar assay. Statistical nonparametric methods were used to confirm statistical significance.

RESULTS

All quinones tested were shown to inhibit JB6 Cl41 cell transformation, to induce apoptosis, AP-1, and NF-kappaB activity, and to inhibit p53 activity. The most promising effects were indicated for compounds containing two isoprene units in a side chain and a methoxyl group at the para-position to a polyprenyl substitution.

CONCLUSIONS

Quinones and demonstrated cancer-preventive activity in JB6 Cl41 cells, which may be attributed to the induction of p53-independent apoptosis. These activities depended on the length of side chains and on the positions of the methoxyl groups in the quinone part of the molecule.

[Effect of synthetic surfactants on some biological properties of non-pathogenic species of the genus Corynebacterium]

The influence of cationic, anionic and non-ionic synthetic surfactants on some biological properties of different representatives of the following species Corynebacterium glutamicum, Corynebacterium ammoniagenes, Corynebacterium vitaeruminis, Corynebacterium variabile and strain Corynebacterium sp. (Brevibacterium stationis) UKM As-719 has been investigated. It has been shown that the action of surfactants is accompanied by the change of cell morphology and loss of ability for Gram-staining, as well as by significant changes of antigenic properties and antibiotic-sensitivity of selected strains of corynebacteria. Nevertheless, no relations were established between the class of surfactants and changes in biological properties of the investigated strains. There was also no correlation between Gram-staining ability after the action of surfactants and change of corynebacteria antigenisity, as well as their antibiotic sensitivity.

Marine Alkaloid Polycarpine and Its Synthetic Derivative Dimethylpolycarpine Induce Apoptosis in JB6 Cells Through p53- and Caspase 3-Dependent Pathways

PURPOSE

Polycarpine from ascidian Polycarpa aurata was previously found to be active against different human tumor cells. In this study, we investigated the antitumor mechanisms of polycarpine and its synthetic derivative, desmethoxyethoxy-polycarpine (dimethylpolycarpine), through the induction of apoptosis. This new knowledge regarding the proapoptotic action of polycarpine and dimethylpolycarpine should lead to a better understanding of their effects and development of a new class of anticancer drugs.

METHODS

Apoptosis was clearly observed by flow cytometry and Western blotting using an antibody against cleaved caspase-3 as an apoptotic marker.

RESULTS

Polycarpines differentially activated p38 kinase, JNKs, and ERKs in JB6 Cl 41 cells. The polycarpines-induced apoptosis was decreased in cells expressing a dominant-negative mutant of JNK. Both compounds stimulated p53-dependent transcriptional activity and phosphorylation. Induction of p53-phosphorylation at serine 15 was suppressed in JNKI and JNK2 knockout cells. Furthermore, polycarpines were unable to induce apoptosis in p53-deficient MEFs in contrast to a strong induction of apoptosis in wild type MEFs, suggesting that p53 is involved in apoptosis induced by polycarpines. The p53 phosphorylation in turn was mediated by activated JNKs.

CONCLUSIONS

These results indicate that all three MAPK signaling pathways are involved in the response of JB6 cells to treatment with polycarpines. Evidence also supports a proapoptotic role of the JNKs signaling pathway in vivo and clearly indicates that JNKs are required for phosphorylation of c-Jun, activation of p53, and subsequent apoptosis induced by polycarpines.