Low-dose action of tryptanthrin and its derivatives against developing embryos of the sea urchin Strongylocentrotus intermedius.

Nine tryptanthrin derivatives, including tryptanthrin itself, were synthesized using different methods, including oxidation of the corresponding isatins to obtain 1-4, the reaction of tryptanthrin 1 with hydrazine and its derivatives to obtain 5-7, and aldol condensation of 1 with acetone and methylethylketone to obtain 8 and 9. The action of 1-9 in doses corresponding to the IC50 against developing embryos of the sea urchin Strongylocentrotus intermedius and in the sperm test allowed us to estimate to potency of all the compounds and to determine which were cytotoxic. In addition, these studies showed that compounds 3, 4, 8, and 9 had a stimulatory effect at lower doses. In particular, the tryptanthrin derivatives stimulated the larval stages of development in surviving embryos at concentrations lower than the IC50.

Highly hydroxylated steroids of the starfish Archaster typicus from the Vietnamese waters.

Five new steroidal compounds, including an unusual glucoside, along with several known steroids were isolated from the starfish Archaster typicus collected in shallow waters of Quang Ninh province (Vietnam). Three new compounds are 27-nor-cholestane derivatives and the other two are 24,26-dihydroxycholestane derivatives. A biogenesis pathway for the unusual side chain of 27-nor-cholestane derivatives is proposed. Isolated compounds presented moderate toxic effects in the sperm- and 8-blastomere tests on embryonal development of the sea urchin Strongylocentrotusintermedius.

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.

Magnetic resonance imaging of mouse Ehrlich carcinoma growth inhibition by thiacarpine, an analogue of cytotoxic marine alkaloid polycarpine.

The anticancer effect of thiacarpine, a synthetic analogue of the known cytotoxic alkaloid polycarpine isolated from the Pacific ascidian Polycarpa aurata, was investigated in vivo in experiments using mouse solid Ehrlich carcinoma tumor as the target. A high-resolution magnetic resonance imaging (MRI) technique using a MR tomograph "PharmaScan" US70/16 (Bruker, Ettlingen, Germany) was used for visualization and quantification of tumor size. Fluorescence microscopy and image analysis were applied to determine Ehrlich carcinoma cell chromatin condensing (apoptosis) and necrosis in Ehrlich carcinoma cells at the action of thiacarpine in in vitro experiments. The scan and size calculations of the tumor and some mouse organs were carried out during the experiments. Thiacarpine in a total dose of 100 mg/kg was found to exhibit the delay in growth of the mouse tumor. The antineoplastic effect of this compound was accompanied by an increase in the lifetime of experimental mice in comparison with the control group of animals. Our data show that the ability of thiacarpine to induce apoptosis in carcinoma cells may contribute to thiacarpine anticancer effects against mice solid Ehrlich carcinoma in vivo detected by MRI.

Steroidal triglycosides, kurilensosides A, B, and C, and other polar steroids from the Far Eastern starfish Hippasteria kurilensis.

Three novel steroidal triglycosides, designated as kurilensosides A, B, and C (1- 3), were isolated along with a new steroidal diglycoside, kurilensoside D (4), and two new (6, 7) and one known (5) polyhydroxysteroid from the alcoholic extract of the Far Eastern starfish Hippasteria kurilensis. Compounds 1-3 are the first triglycosides containing two carbohydrate chains found from starfish. The structures of 1-7 were elucidated by spectroscopic methods (mainly 2D NMR) and chemical derivatization. Glycosides 1-4 and steroids 6 and 7 inhibited sea urchin egg fertilization by sperm preincubated with these compounds.

Influence of cucumariosides upon intracellular [Ca2+]i and lysosomal activity of macrophages.

Biological effects of the triterpene glycosides, cucumariosides A(2)-2 and A(7)-1 from the edible sea cucumber Cucumaria japonica and their aglycones were investigated using embryos of the sea urchin Strongylocentrotus nudus and the BALB/C line mouse peritoneal macrophages. Cucumariosides were highly cytotoxic in a sea urchin embryo development test with EC(50) values of 0.3 and 1.98 microg/mL, respectively. The aglycone was completely lacking in cytotoxicity. In subtoxic concentrations (0.001-0.1 microg/mL), cucumarioside A(2)-2 showed more then 2-fold stimulation of lysosomal activity and induced a rapid short-term increase in cytosolic Ca(2+) content in mouse macrophages. The maximal stimulatory effect was detected after 1-2 h of cultivation of cells with this glycoside. Cucumarioside A(7)-1 demonstrated more weak effects and even slightly inhibited lysosomal activity, while the aglycone was completely ineffective. At the toxic concentration (1 microg/mL), cucumarioside A(2)-2 induced the sharp irreversable increase of intracellular Ca(2+) concentration. We suggested that cucumariosides, especially A(2)-2, may act as Ca(2+) agonists due to their membranolytic properties.

Mycalosides B-I, eight new spermostatic steroid oligoglycosides from the sponge Mycale laxissima.

New steroidal oligoglycosides mycalosides B-I (2-9) have been isolated from the polar extract of the Caribbean sponge Mycale laxissima, and their structures have been elucidated by 1D and 2D NMR ((1)H, (13)C, DEPT, COSY-45, COSY-RCT, HSQC, HMBC, and NOESY spectra) and MALDI-TOF mass spectrometry. Mycalosides B (2) and C (3) were shown to be 27- and 28-nor derivatives of the previously known tetraoside mycaloside A (1). Mycaloside D (4) differs from 1 only in the presence of an additional acetyl group in the carbohydrate moiety. Mycaloside E (5) was structurally identified as a 28-nor-4-dehydroxy derivative of 1. Mycalosides F-H (6-8), differing from each other by the structures of their side chains and nonacetylated (7, 8) or acetylated (6) tetrasaccharide carbohydrate moieties, have new 5(6)-unsaturated 3 beta,4 beta,21-trihydroxy-15-keto-steroidal aglycons. Mycaloside I (9) is a tetraoside of a new 7,24(28)-diunsaturated 3beta,15 beta,29-trihydroxystigmastane aglycon. It was established that the total fraction of the mycalosides as well as mycalosides A (1) and G (7) inhibit the fertilization of eggs by sperm of the sea urchin Strongylocentrotus nudus preincubated with these compounds.

Influence of polyhydroxysteroids on [Ca(2+)](i).

Recently, we have shown that two biologically active, disulfated polyhydroxysteroids from the Pacific brittle star Ophiopholis aculeata stimulate Ca(2+) influx into different cell types. In the present study, 45Ca(2+) and two fluorescent calcium probes, quin-2/AM and fura-2/AM, were employed to investigate the course and amplitude of calcium signals induced in different mouse cells using an radio-isotope, spectrofluorimetry, and microcytofluorimetry techniques. The cytotoxic and hemolytic effects were not observed for both steroids at the wide range of concentrations. Steroids did not influence [3H]-uridine incorporation in a variety of cells. The investigated steroids stimulated a rapid increase in cytosolic Ca(2+) content in Ehrlich mouse carcinoma cells, mouse spleen lymphocytes, and mouse peritoneal macrophages in the concentration range 1-100 microg/ml on a dose-dependent basis. Blockers of L-type calcium channels, such as verapamil, diltiazem, nifedipine (1 x 10(-7)M), and 1mM EGTA, inhibited this process and reduced the response of cells to steroid application. The stimulatory effect of steroids on human fibroblast proliferation and mouse macrophage lysosome activity was observed also. It is suggested that the investigated compounds may act as Ca(2+)-agonists and increase Ca(2+)-transport across cell membranes.