Jesús G. Díaz

Eight carotane sesquiterpenes from Ferula linkii

Abstract Six new carotane sesquiterpenes, the p -methoxybenzoate-, isovalerate- and veratrate of epoxyjaesckeanadiol, the 1-acetate, 5-isovalerate of ferulinkiol, the 1-acetate, 5-isovalerate of lapiferol and the 1-acetate of lapiferol, and the already known p -methoxybenzoate of jaesckeanadiol and lapiferin have been isolated from Ferula linkii .

Trifolin acetate-induced cell death in human leukemia cells is dependent on caspase-6 and activates the MAPK pathway.

In the present study we demonstrated that the flavonoid derivative trifolin acetate (TA), obtained by acetylation of naturally occurring trifolin, induces apoptosis. Associated downstream signaling events were also investigated. TA-induced cell death was prevented by the non-specific caspase inhibitor z-VAD-fmk and reduced by the presence of the selective caspase inhibitors z-LEHD-fmk (caspase-9), z-DEVD-fmk (caspase-3) and z-VEID-fmk (caspase-6). The apoptotic effect of TA was associated with (i) the release of cytochrome c from mitochondria which was not accompanied by dissipation of the mitochondrial membrane potential (ΔΨm), (ii) the activation of the mitogen-activated protein kinases (MAPKs) pathway and (iii) abrogated by the over-expression of Bcl-2 or Bcl-xL. TA-induced cell death was attenuated by inhibition of extracellular signal-regulated kinases (ERK) 1/2 with U0126 and inhibition of p38MAPK with SB203580. In contrast, inhibition of c-Jun NH2-terminal kinase (JNK) by SP600125 significantly enhanced apoptosis. Although reactive oxygen species (ROS) increased in response to TA, this did not seem to play a pivotal role in the apoptotic process since different anti-oxidants were unable to provide cell protection. The present study demonstrates that TA-induced cell death is mediated by an intrinsic-dependent apoptotic event involving mitochondria and MAPK, and through a mechanism independent of ROS generation.

Carotane sesquiterpenes from Ferula linkii

Abstract Four new carotane sesquiterpenes have been isolated from Ferula linkii. They have been identified as the 5-isovalerate of isolancerotriol, the 5-isovalerate and 5-angelate of isolancerotetrol, and the 5-isovalerate of epoxyisolancerotetrol.

Astragalin heptaacetate-induced cell death in human leukemia cells is dependent on caspases and activates the MAPK pathway

Flavonoids are naturally occurring polyphenolic compounds and are among the most promising anticancer agents. Here we demonstrate that the flavonoid derivative astragalin heptaacetate (AHA) induces cell death. This was prevented by the non-specific caspase inhibitors z-VAD-fmk and Q-VD-OPH, and reduced by the selective caspase-4 inhibitor z-LEVD-fmk. AHA-induced cell death was found to be: (i) associated with the release of cytochrome c, (ii) suppressed by the overexpression of Bcl-x(L), (iii) amplified by inhibition of extracellular signal-regulated kinases (ERKs) 1/2 and c-jun NH(2)-terminal kinases/stress activated protein kinases (JNK/SAPK) signaling, and (iv) completely abrogated by the free-radical scavenger N-acetyl-l-cysteine.

Chromenes and benzofurans from Ageratina glechonophylla

Abstract A re-examination of the aerial part of Ageratina glechonophylla yielded spathulenol (1,6-dihydroxy-4(14)-eudesmene) as a natural product, six known chromenes, a mixture of three dimeric chromenes, four thymol derivatives and 3-(hydroxymethyl)-3-(acetoxymethyl)-and 3-(isobutyryloxymethyl)-6-methylbenzofuran were also identified in this plant.

Synthesis of α-Metoylene-γ-Lactones in Furanosidic Systems

Abstract Synthesis of stereoisomeric α-methylene-γ-lactones in furanose-and furanuronoamide derivatives was easily accomplished by Reformatsky Reaction with ethyl bromcmethylacrylic ester and zinc. Pyridinium chlorochromate/3A molecular sieve powder showed to be an excellent reagent for the oxidation of secondary hydroxyl groups of a furanose system and of α-hydroxy amides.

Diterpenes and other constituents of Eupatorium salvia

Abstract An ethanol extract of the aerial parts of Eupatorium salvia was re-examined and five labdane-type diterpenes, one sesquiterpene and two flavonoids were obtained. Structures were elucidated by spectroscopic methods and chemical transformations.

Triterpenes from Ferula linkii

Abstract Two new natural triterpenes, 3β-acetoxyolean-9,12-diene and 3β-acetoxy-6β-hydroxyolean-9,12-diene, were isolated from Ferula linkii .

Carotdiol esters from Ferula linkii

Abstract The new carotane sesquiterpenes carotdiol acetate and carotdiol veratrate have been isolated from Ferula linkii . The known sesquiterpene daucol and the phenylpropanoids laserine, laserine oxide and helmanticine, have also been obtained from this plant.

Distribution of acetylenes and sesquiterpene lactones in Argyranthemum from Tenerife

Four Argyranthemum species endemic to the Canary Islands were studied, yielding eight acetylene derivatives: frutescin, demethylfrutescin, frutescinol acetate, capillol acetate, capillol, capillon, demethoxyfrutescinol acetate, foeniculacin (not previously described), the thiophene derivative 6-(2-thienyl)-2,4-hexadienoic acid N-isobutylamide and three sesquiterpene lactones: 8-deoxycumambrin, novanin and α-tetrahydrosantonin. Capillol, demethoxyfrutescinol acetate and α-tetrahydrosantonin are new natural products. The distribution of these substances in the roots, stems, leaves and flowers of the four taxa is given.