Natural product protulactone A: Total synthesis from D-galactose, X-ray analysis and biological evaluation

Synthesis of protulactone A (PLA, 1) and twelve of its analogues have been achieved starting from D-galactose. PLA was isolated in the crystalline state, and its crystal structure was determined utilizing X-ray crystallography, which confirmed the assumed stereochemistry at all stereocenters. All tested compounds displayed antiproliferative activity against a panel of tumour cell lines, and all of them were non-cytotoxic toward the normal cells (MRC-5). Natural product PLA (1) was the most active against the K562 and MCF-7 cell lines (IC50 6.52 and 2.20 μM, respectively). Some of the synthesized derivatives showed very potent cytotoxicity, especially analogues 11, 13 and 15 (IC50 1.08–1.14 μM against MCF-7), and 9 and 14 (IC50 1.29 and 1.64 μM against K562). SAR analysis indicated important structural motifs for antiproliferative activity. Unfortunately, PLA (1), its C-7 epimer (2) and demethylated analogue (3) did not display a significant antimicrobial activity (two Gram-positive and two Gram-negative bacteria and one fungal strain) and they also cannot affect the ability to modulate bacterial communication

Synthesis and biological evaluation of new pyrazole- and tetrazole-related C-nucleosides with modified sugar moieties

3(5)-Carboxamido-4-(beta-D-ribofuranosyl)pyrazoles bearing 2-benzamido (15) and 3-mesyloxy (29) isosteric groups, as well as the tetrazole C-nucleosides with 2-benzamido-2-deoxy-beta-D-ribofuranose (19) and 3-azido-3-deoxy-beta-D-xylofuranose (36) as sugar segments, have been synthesized starting from D-glucose, by utilizing the 2,5-anhydro-D-glucose ethylene acetal derivatives 1 and 20 as divergent intermediates. The C-nucleosides 15 and 36 were shown to be moderate inhibitors of the in vitro growth of both N2a and BHK 21 tumour cell lines, whereas 29 showed a selective, although not potent cytotoxic activity against N2a cells. Compound 29 also showed a moderate in vitro antiviral activity towards the rabies virus. (C) 2002 Elsevier Science Ltd. All rights reserved

Synthesis and antiproliferative activity of (5R)-cleistenolide and analogues

(5R)-Cleistenolide and a few related analogues have been synthesized starting from d-glucose. The key steps of the synthesis included a Z-selective Wittig olefination and an intramolecular Mitsunobu reaction with an inversion of configuration at the C-5 position. In vitro antiproliferative activity of synthesized compounds was tested on a panel of eight human tumour cells and against a single normal cell line (MRC-5). The majority of tested compounds showed strong antiproliferative effects on certain human tumour cells and all of them showed negligible toxicity to normal foetal lung fibroblasts (MRC-5). The most active compound obtained in this work is lactone 5, which in MDA-MB 231 cell culture showed the same activity as doxorubicin (IC50 0.09 μM). Strong antiproliferative activities of analogues 2, 5 and 6 were recorded in the K562 cell line (IC50 0.21, 0.34 and 0.33 μM, respectively), in which they showed very similar activities to doxorubicin (IC50 0.25 μM). A performed SAR study revealed that a change in the stereochemistry at the C-5 position may increase the activity of resulting stereoisomers

Dithiophenes and other constituents of roots of Centaurea nicolai

Centaurea nicolai Bald. is an endemic species found in the Mediterranean part of Montenegro, and in Albania. Roots of C. nicolai were collected on the south slopes of mountain Rumija on the Adriatic coast of Montenegro

Cellular and Molecular Characteristics of Novel Colon Cancer Cell Line

22nd Biennial Congress of the European-Association-for-Cancer-Research, Jul 07-10, 2012, Barcelona, Spai