New Hybrids Derived from Podophyllic Aldehyde and Diterpenylhydroquinones with Selectivity toward Osteosarcoma Cells.

A new family of molecular hybrids, between cyclolignans related to podophyllic aldehyde and several diterpenylnaphthohydroquinones (DNHQ), was prepared and its biological activity evaluated in several human solid tumor cell lines, which are representative of the most prevalent solid tumors in the Western world. Both cyclolignan and quinone fragments were linked through aliphatic or aromatic spacers. The new hybrid family was evaluated for its cytotoxicity, and it was found that the hybrids were several times more potent against the osteosarcoma cell line MG-63 than against MCF-7 and HT-29 cell lines. The presence of an aromatic ring in the linker gave the most potent and selective agent, improving the cytotoxicity of the parent compounds. Cell cycle studies demonstrated that this hybrid induces a strong and rapid apoptotic effect and arrests cells at the G2/M phase of the cell cycle, in the same way that the parent compound podophyllic aldehyde does.

Cytotoxic Terphenyl Neolignans from Fungus Terana coerulea: New Natural Corticins D and E. and Revised Structure for Corticin A.

The cobalt crust fungus Terana coerulea (Phanerochaetaceae family) was selected for a bio-guided study after an ethnobotanical survey at the Irati's Forest (Navarra, Spain) for its local use as antibiotic. Six extracts of increasing polarity, from hexane to hot water, were obtained from powdered dry fungi and tested for cytotoxicity against four human tumour cell lines and one non-tumour primary cell culture. From the most cytotoxic, EtOAc extract, we isolated and identified three terphenyl neolignans: two of them new natural products, named corticins D and E, and one previously described as corticin A, whose earlier structure has been revised. Their structural elucidation and biological evaluation as cytotoxic agents are described.

Synthesis and antifungal activity of terpenyl-1,4-naphthoquinone and 1,4-anthracenedione derivatives.

The antifungal evaluation of twenty seven simple and heterocycle-fused prenyl-1,4-naphthoquinones and 1,4-anthracenediones was performed in vitro against human pathogenic yeasts (Candida spp.) and filamentous fungi (Aspergillus spp., Fusarium spp., and Trichophyton spp.). The synthetic strategy used to obtain the quinone derivatives was initially based on the Diels-Alder cycloaddition between myrcene and several p-benzoquinone derivatives, followed by cyclisation of the prenyl side chain in the case of anthracene-1,4-diones. The most promising compounds, displaying MIC values in the low µg/mL range, were those bearing one or two chlorine atoms attached to the quinone ring. Time-kill curves determined for the most potent compounds showed their fungistatic mode of action similar to that of itraconazole.

Lignopurines: a new family of hybrids between cyclolignans and purines. Synthesis and biological evaluation.

A new family of hybrids between cyclolignans related to podophyllic aldehyde, a non-lactonic cyclolignan, and purines were prepared and evaluated against several human tumour cell lines. Both fragments, cyclolignan and purine, were linked through aliphatic and aromatic chains. The influence on the cytotoxicity of the purine substitution and the nature of the linker is analyzed. The new family was slightly less cytotoxic than the parent podophyllic aldehyde, although the selectivity is maintained or even improved and among the linkers used, the presence of an aromatic ring gave the most potent and selective derivatives within the new series tested. Cell cycle and confocal studies demonstrate that these derivatives interfere with the tubulin polymerization and arrest cells at the G(2)/M phase, in the same way than the parent compounds podophyllotoxin and podophyllic aldehyde do.

Synthesis and biological evaluation of new podophyllic aldehyde derivatives with cytotoxic and apoptosis-inducing activities.

Several series of nonlactonic podophyllic aldehyde analogues were prepared and evaluated against several human tumor cell lines. They had different combinations of aldehyde, imine, amine, ester, and amide functions at C-9 and C-9' of the cyclolignan skeleton. All the compounds synthesized showed cytotoxicity levels in the microM range and below. Within the new series tested, compounds having an aldehyde or imine at C-9 and an ester at C-9' were the most potent, with GI(50) values in the nM range, some of them being several times more potent against HT-29 and A-549 carcinoma than against MB-231 melanoma cells. Cell cycle studies and analysis of the microtubule-disrupting capacity have demonstrated the existence of two different mechanisms of cell death induction for compounds with closely related structures.

Synthesis and cytotoxic evaluation of C-9 oxidized podophyllotoxin derivatives.

A series of podophyllotoxin and podophyllic aldehyde derivatives, lacking the lactone ring and oxidized at C-9 position, has been prepared. The functionalities considered at C-9 were carboxylic acids and several derivatives such as esters, amides, nitriles or anhydrides. The synthesized compounds were cytotoxic at the micromolar level, though less potent and selective than the parent compounds, revealing the influence of the C-9 electrophilic character on the potency and selectivity of these cyclolignans.

Synthesis, characterisation and cytotoxicity of chloro derivatives of prenylnaphthohydroquinone.

From the Diels-Alder adduct between alpha-myrcene and 2-chloro-1,4-benzoquinone, a family of chloro derivatives of prenylnaphthohydroquinone have been synthesised and evaluated for their cytotoxicity against 14 neoplastic cell lines.