New tridecapeptides of the theonellapeptolide family from the Indonesian sponge Theonella swinhoei

• Annamaria Sinisi,
• Barbara Calcinai,
• Carlo Cerrano,
• Henny A. Dien,
• Angela Zampella,
• Claudio D’Amore,
• Barbara Renga,
• Stefano Fiorucci and
• Orazio Taglialatela-Scafati

Beilstein J. Org. Chem. 2013, 9, 1643–1651, doi:10.3762/bjoc.9.188

• show four valine residues. The structures of the compounds, isolated along with the known theonellapeptolide Id, were determined by extensive 2D NMR and MS/MS analyses followed by application of Marfey’s method. The isolated peptides exhibited moderate antiproliferative activity against HepG2 cells, a

• hepatic carcinoma cell line. Keywords: antiproliferative activity; cyclic peptides; marine metabolites; theonellapeptolides; 2D NMR; Introduction Three decades of extensive chemical investigation [1] have clearly evidenced that marine sponges of the genus Theonella (Lithistida, Theonellidae) are

• during the present investigation (1–3) have been evaluated for their antiproliferative activity against HepG2 cells, a hepatic carcinoma cell line. As reported in Figure 4, all tested compounds showed antiproliferative activity at low micromolar doses, with a similar pattern of potency. At the dose 10 μM

Chemical modification allows phallotoxins and amatoxins to be used as tools in cell biology

• Jan Anderl,
• Hartmut Echner and
• Heinz Faulstich

Beilstein J. Org. Chem. 2012, 8, 2072–2084, doi:10.3762/bjoc.8.233

• incubation time (Table 1). Phalloidin displayed no antiproliferative activity up to a concentration of 10−3 M in the culture medium. In contrast, the most lipophilic ester derivative, phalloidin oleate (1e), showed an IC50 value of proliferation inhibition of 2.5 × 10−6 M, and was thus ca. 1000 times more

• , were highly toxic for mouse fibroblasts, and their antiproliferative activity was comparable to the most lipophilic derivative, phalloidin oleate (Figure 4a). Their toxicity was found to be dependent on the configuration of the polymer, since phalloidin bound to D-configurated polylysine was about 10

Unprecedented deoxygenation at C-7 of the ansamitocin core during mutasynthetic biotransformations

• Tobias Knobloch,
• Gerald Dräger,
• Wera Collisi,
• Florenz Sasse and
• Andreas Kirschning

Beilstein J. Org. Chem. 2012, 8, 861–869, doi:10.3762/bjoc.8.96

• mutants and mutasynthetic approaches. We suggest that the formation of these derivatives is based on elimination at C-7/C-8 followed by reduction(s) of the intermediate enone. In bioactivity tests, only ansamitocin derivatives bearing an ester side chain at C-3 showed strong antiproliferative activity

• -proansamitocin 8 (3.5 mg/L) and two diastereomeric byproducts 9a and 9b (7.6 mg/L; 1:1 ratio) from the fermentation broth of A. pretiosum Δasm12/21 (Figure 1). We also showed that none of these proansamitocin derivatives exhibit antiproliferative activity. Herein, we describe the unprecedented formation of

• )ansamitocin derivatives lacking the ester side chain at C-3 (11b, 11g–h, 12–16) do not show any antiproliferative activity (IC50 > 800 nM) for at least two of the cell lines listed in Table 1. Compounds 11c–e, bearing the ester side chain at C-3, predominantly showed activities in the pM range. As seen also

Marilones A–C, phthalides from the sponge-derived fungus Stachylidium sp.

• Celso Almeida,
• Stefan Kehraus,
• Miguel Prudêncio and
• Gabriele M. König

Beilstein J. Org. Chem. 2011, 7, 1636–1642, doi:10.3762/bjoc.7.192

• activity towards three cancer cell lines (NCI-H460, MCF7 and SF268). Marilone A and C (1, 3) showed weak antiproliferative activity with an average GI50 of 36.7 and 26.6 µM, respectively (see Supporting Information File 1). Marilone B (2) was assayed in a panel of 44 psychoactive receptors, including 11

Efficient syntheses of 25,26-dihydrodictyostatin and 25,26-dihydro-6-epi-dictyostatin, two potent new microtubule-stabilizing agents

• María Jiménez,
• Wei Zhu,
• Andreas Vogt,
• Billy W. Day and
• Dennis P. Curran

Beilstein J. Org. Chem. 2011, 7, 1372–1378, doi:10.3762/bjoc.7.161

• , PA 15260, USA Department of Pharmaceutical Sciences, School of Pharmacy, 3501 Terrace Street, University of Pittsburgh, Pittsburgh, PA 15261 USA 10.3762/bjoc.7.161 Abstract The dictyostatins are powerful microtubule-stabilizing agents that have shown antiproliferative activity against a variety of

• microtubule-stabilizing agents include taxanes, epothilones, and discodermolides, among others [3][4]. Dictyostatin (1a) is an exceptionally potent microtubule-stabilizing agent that has shown antiproliferative activity in a variety of human cancer cell lines in the low nanomolar range. Isolated first in 1994

Colchitaxel, a coupled compound made from microtubule inhibitors colchicine and paclitaxel

• Karunananda Bombuwala,
• Thomas Kinstle,
• Vladimir Popik,
• Sonal O. Uppal,
• James B. Olesen,
• Jose Viña and
• Carol A. Heckman

Beilstein J. Org. Chem. 2006, 2, No. 13, doi:10.1186/1860-5397-2-13

• , for antiproliferative activity of paclitaxel and vinorelbine individually, but synergy with concentrations as low as 3 nM and 0.01 nM respectively [51]. Thus, differing model systems yielded results variously suggesting antagonistic, non-additive, or synergistic effects. However, there is evidence