Synthesis of a new ent-cyclozonarone angular analog, and comparison of its cytotoxicity and apoptotic effects with ent-cyclozonarone.

The synthesis of a newangular analog 11 of cyclozonarone was achieved via Diels-Alder reaction between a sesquiterpene-1,3-diene and 1,4-benzoquinone. The cytotoxic activity of ent-cyclozonarone [(+)-10] and the angular (-)-cyclozonarone analog 11 has been determined in three human cancer cell lines and in normal fibroblasts using the sulforhodamine B assay. The analyzed isomers induce cell death in different cancer cell lines by eliciting nuclear condensation and fragmentation, decreasing mitochondrial membrane permeability and increasing caspase-3 activity, all traits indicating apoptosis, with the effects of (+)-10 being stronger than those of 11 in all cases.

Depsides and triterpenes in Pseudocyphellaria coriifolia (lichens) and biological activity against Trypanosoma cruzi.

The lichen Pseudocyphellaria coriifolia is a species endemic to southern South America. From the lichen thallus, methyl evernate, tenuiorin and three hopane triterpenoids were isolated and identified as the main lichen constituents. Their trypanocidal effects were screened against epimastigotes of Trypanosoma cruzi. The results of the biological test showed that some hopane terpenoids exhibit antiparasitic properties.

Synthesis and antitumor activity of diterpenylhydroquinone derivatives of natural ent-labdanes.

Two new compounds 2ß-acetoxy-15-phenyl-(22,25-acetoxy)-ent-labda-8(17), 13(E)-diene (9) and 2ß-hydroxy-15-phenyl-(22,24,26-trimethoxy)-ent-labda-8(17),13(E)-diene (10) have been prepared by an Electrophilic Aromatic Substitution (EAS) reaction between diterpenyl allylic alcohols and 1,4-hydroquinone or 1,3,5-trimethoxybenzene using BF(3).Et(2)O as a catalyst. These compounds, along with a series of natural ent-labdanes 3-8, have been evaluated for their in vitro cytotoxic activities against cultured human cancer cells of PC-3 and DU-145 human prostate cancer, MCF-7 and MDA-MB-231 breast carcinoma and dermal human fibroblasts (DHF). Some compounds displayed inhibition at µM IC(50 )values.

Synthesis of two new hemisynthetic diterpenylhydroquinones from natural ent-labdanes.

The synthesis and structural determination of two new diterpenylhydroquinones: 2beta-acetoxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene(1) and 2beta-hydroxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-dieneis reported (2). These compounds were obtained by coupling via Electrophilic Aromatic Substitution (EAS) of 1,4-hydroquinone with primary or tertiary allyl alcohol derivatives of the natural ent-labdanes 3 and 4. With this new method, the best results were observed when mixtures of the primary alcohol derivatives 5-6 (26% yield of compound 1) and diol derivatives 9-10 (28% yield of compound 2) were used.

Oxidative degradations of the side chain of unsaturated ent-labdanes. Part II.

A route for the degradation of the side chain of ent-labdane derivatives has been devised, giving the useful synthon 2beta,12-dihydroxy-13,14,15,16,17-pentanor-ent-labdane-8-one (8). The use of this compound in the preparation of terpenylquinone derivatives shall be reported elsewhere. In addition we have synthesized the compound 2beta,12-diacetoxy-8beta,17-epoxy-13,14,15,16-tetranor-ent-labdane (10), which upon catalytic epoxide ring opening in alkaline or acid media gave rise in all cases to the formation of tricyclicc ompounds.