Papers by Hector Carrasco
Boletin De La Sociedad Chilena De Quimica, 1998
Molecules, 2014
Twelve drimanes, including polygodial (1), isopolygodial (2), drimenol (3), confertifolin (4), an... more Twelve drimanes, including polygodial (1), isopolygodial (2), drimenol (3), confertifolin (4), and isodrimenin (5), were obtained from natural sources. Semi-synthetic derivatives 6-12 were obtained from 1 and 2, and cytotoxic activity was evaluated in vitro against cancer cell lines (HT-29, MDA-MB231, DHF, MCF-7, PC-3, DU-145, and CoN). IC50 values were determined at concentrations of 12.5-100 µM of each compound for 72 h. In addition, it was found that polygodial (1), 8, and 12 induced changes in mitochondrial membrane permeability in CoN, MCF-7, and PC-3 cells.
Molecules, 2009
The synthesis and structural determination of two new diterpenylhydroquinones: 2β-acetoxy-15-phen... more The synthesis and structural determination of two new diterpenylhydroquinones: 2β-acetoxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene (1) and 2β-hydroxy-15-phenyl-(22,25-dihydroxy)-ent-labda-8(17),13(E)-diene is 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 entlabdanes 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.
Molecules, 2007
A selective route for the degradation of the unsaturated side chain of ent-labdanes has been devi... more A selective route for the degradation of the unsaturated side chain of ent-labdanes has been devised, giving two useful synthons: 2β-acetoxy-14,15,17-trinor-ent-labdane-8,13dione (5) and 2β-acetoxy-14,15-dinor-ent-labd-8(17)-en-13-one (7), the use of which for the preparation of terpenylquinone derivatives shall be reported elsewhere.
Molecules, 2011
Catechols were synthesized from safrole. Nine derivatives were prepared and assessed for antiprol... more Catechols were synthesized from safrole. Nine derivatives were prepared and assessed for antiproliferative effects using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. The derivatives 4-allylbenzene-1,2-diol (3), 4 4-[3-(acetyloxy)propyl]-1,2-phenylene diacetate (6) and 4-[3-(acetyloxy)propyl]-5-nitro-1,2-phenylene diacetate (10) showed higher cytotoxicity than the parent compound 2 in tests performed on two breast cancer cell lines (MCF-7 and MDA-MB-231). The IC 50 values of 40.2 ± 6.9 μM, 5.9 ± 0.8 μM and 33.8 ± 4.9 μM, respectively, were obtained without toxicity towards dermal human fibroblast (DHF cells).
Journal of the Chilean Chemical Society, 2010
Safrole from sassafras oil (Ocotea pretiosa Mez., Lauraceae), is an abundant natural product show... more Safrole from sassafras oil (Ocotea pretiosa Mez., Lauraceae), is an abundant natural product showing interesting functionality and chemical structure. Starting from safrole, nine derivatives were prepared and assessed for antiproliferative effect using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. Some safrole derivatives, (2E)-3-(3',4'-methylenedioxi)phenyl acrylaldehyde (3) and 4-allyl-5nitrobenzene-1,2-diol (4) presented better antiproliferative effect than the parent compound on two breast cancer cell lines (MCF-7 and MDA-MB-231) and one human colorectal cancer cell line (DLD-1) with IC 50 values of 55.0 + 7.11 µM, 37.5 + 2.65 µM and 44.0 + 6.92 µM, respectively, without toxicity towards dermal human fibroblast (DHF cells).
Journal of the Brazilian Chemical Society, 2008
Propriedades antioxidante e anticancerígena foram relatadas para o Eugenol (4-alil-2metoxifenol) ... more Propriedades antioxidante e anticancerígena foram relatadas para o Eugenol (4-alil-2metoxifenol) (1). Na tentativa de aumentar a atividade intrínseca deste composto natural, alguns derivados foram sintetizados. O eugenol foi extraído do óleo de cravo da Índia e seus análogos (2-6) foram obtidos por reações de acetilação e nitração. Eugenol (1) e seus análogos (2-6) foram avaliados in vitro frente a duas linhagens de células de câncer humanas: DU-145 (células de câncer de próstata, insensíveis a andrógeno) e KB (células de carcinoma escamoso oral). A viabilidade celular foi avaliada por ensaios com sal de tetrazólio. A liberação de desidrogenase lática (LDH) também foi investigada para avaliar a toxicidade celular como um resultado do rompimento celular subseqüente à ruptura da membrana. Todos os compostos apresentaram atividade inibitória sobre o crescimento das células cancerosas examinadas. Os resultados obtidos demonstram que os compostos 5-alil-3-nitrobenzeno-1,2-diol (3) e acetato de 4-alil-2-metoxi-5-nitrofenol (5) foram significativamente mais ativos que o eugenol (p < 0,001), com valores de IC 50 em células DU-145 de 19,02 × 10-6 e 21,5 × 10-6 mol L-1 respectivamente, sugerindo que a presença dos grupos nitro e hidroxila podem ser importantes na atividade destes compostos. Os resultados também parecem indicar que a morte por apoptose está sendo induzida em células KB e DU-145. Nas condições experimentais avaliadas, não foi observado qualquer aumento estatisticamente significativo na liberação de LDH pelas células de câncer quando tratadas com eugenol e seus análogos. Eugenol (4-allyl-2-methoxyphenol) (1) has been reported to possess antioxidant and anticancer properties. In an attempt to enhance intrinsic activity of this natural compound, some derivatives were synthesized. Eugenol was extracted from cloves oil and further, the eugenol analogues (2-6) were obtained through acetylation and nitration reactions. Eugenol (1) and its analogues (2-6) were examined by in vitro model of cancer using two human cancer cell lines: DU-145 (androgeninsensitive prostate cancer cells) and KB (oral squamous carcinoma cells). Cell viability, by tetrazolium salts assay, was measured. Lactic dehydrogenase (LDH) release was also investigated to evaluate the presence of cell toxicity as a result of cell disruption, subsequent to membrane rupture. In the examined cancer cells, all compounds showed cell-growth inhibition activity. The obtained results demonstrate that the compounds 5-allyl-3-nitrobenzene-1,2-diol (3) and 4-allyl-2-methoxy-5-nitrophenyl acetate (5) were significantly (p < 0,001) more active than eugenol, with IC 50 values in DU-145 cells of 19.02 x 10-6 and 21.5 × 10-6 mol L-1 , respectively, and in KB cells of 18.11 × 10-6 and 21.26 × 10-6 mol L-1 , respectively, suggesting that the presence of nitro and hydroxyl groups could be important in the activity of these compounds. In addition, our results seem to indicate that apoptotic cell demise appears to be induced in KB and DU-145 cells. In fact, in our experimental conditions, no statistically significant increase in LDH release was observed in cancer cells treated with eugenol and its analogues.
Journal of the American Chemical Society, 2001
The design concept of functional solids relies on controlling the topology of crystal packing thr... more The design concept of functional solids relies on controlling the topology of crystal packing through exploitation of weak intermolecular forces. In the context of cyclic aggregates, the ability to anticipate the consequences of ring constituents and their stereochemistries on ring conformation is vitally important since even an apparently slight structural change effected on molecules can dramatically alter the crystal structure. We have found that solid-state structures formed by hydroxy acids with a general structure (()-1 depend on steric interactions. Thus, with the exception of molecules 1b and 1e, compounds (()-1a-(()-1m, which possess bulky and conformationally rigid substituents, aggregate by forming tapes and sheets by alternating (+) and (-) subunits held together through carboxylic acid-to-alcohol hydrogen bonds. Homologue (()-1n, with conformationally flexible substituents which allow conformational deformation, gives, by incorporation of molecules of water, an efficient hexagonal assembly which extends to the third dimension to form tubular H-bonding networks. Each puckered channel can be described as interconnected closely packed hexagons in chairlike conformations. The ethyl groups presented in (()-1n gave the volume required to lock the inner hexagonal wall into a rigid structure. Attempts to obtain cyclic aggregates using small substituents, compounds (()-1o-(()-1q, failed. The observed supramolecular assemblies of the anhydrous compounds can be classified into one-dimensional strands and two-dimensional sheets, while three-dimensional networks are present only in the hydrated molecules (1b, 1e, and 1n). The crystal structure of the anhydrous (()-1n compound confirms the important role played by water molecules in the formation of tubular structures.
Acta Crystallographica Section E Structure Reports Online, 2006
Molecules in the title crystal structure, C20H24O4, are linked into chains of R 4 4(8) rings alon... more Molecules in the title crystal structure, C20H24O4, are linked into chains of R 4 4(8) rings along [010] and these chains are linked into sheets via weak C—H...π(arene) interactions. These sheets are, in turn, linked via weak C—H...π(arene) and C—H...O interactions into a three-dimensional network. The ethyl substituent is disordered over two sites with refined occupancies of 0.700 (5) and 0.300 (5).
Acta Crystallographica Section E Structure Reports Online, 2006
Molecules of the title compound, C12H13NO5, are linked into chains via weak C—H...π(allyl) intera... more Molecules of the title compound, C12H13NO5, are linked into chains via weak C—H...π(allyl) interactions and these chains are linked into sheets via C—H...O contacts; the sheets, in turn, are interconnected via carbonyl–carbonyl and nitro–π stacking interactions to form a three-dimensional crystal structure.
Journal of The American Chemical Society, 2001
The design concept of functional solids relies on controlling the topology of crystal packing thr... more The design concept of functional solids relies on controlling the topology of crystal packing through exploitation of weak intermolecular forces. In the context of cyclic aggregates, the ability to anticipate the consequences of ring constituents and their stereochemistries on ring conformation is vitally important since even an apparently slight structural change effected on molecules can dramatically alter the crystal structure. We have found that solid-state structures formed by hydroxy acids with a general structure (+/-)-1 depend on steric interactions. Thus, with the exception of molecules 1b and 1e, compounds (+/-)-1a-(+/-)-1m, which possess bulky and conformationally rigid substituents, aggregate by forming tapes and sheets by alternating (+) and (-) subunits held together through carboxylic acid-to-alcohol hydrogen bonds. Homologue (+/-)-1n, with conformationally flexible substituents which allow conformational deformation, gives, by incorporation of molecules of water, an ...
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Papers by Hector Carrasco