Abstract: Sapium macrocarpum (Euphorbiaceae) is a tropical tree located mainly in the southern part of Mexico and in Central America, and it is used in the Mayan traditional medicine for the treatment of several skin diseases. The dichloromethane-MeOH extract of the aerial parts displayed cytotoxic activity against certain cancer cell lines. Lupeol (1), lupenone (2), sitostenone (3), β-sitosterol (4), stigmasterol (5), sitosteryl β-D-glucopyranoside (6) and the rare diterpene tonantzi tlolone A (7) were characterized from this extract. The structural analysis allowed the 1H NMR reassignments for H-12α and H-12β, and for H-13α and H-13β of tonantzitlolone A (7). The cytotoxic activity of compounds 1-3, 6 and 7 was evaluated against selected cancer cell lines. Compounds 3, 6 and 7 displayed clear activity against K562 (leukemia). This is the first report on the chemical constituents of S. macrocarpum, and points out that this species is an additional source of tonantzitlolone A. Compound 7 has only been reported previously from species of the Stillingia, Sebastiania and Sapium genera, which belong to the Hippomaninae subtribe of the family Euphorbiaceae.

Resumen: Sapium macrocarpum (familia Euphorbiaceae) es un árbol localizado en la parte central de México y en Sudamérica, el cual es usado en la medicina tradicional Maya para el tratamiento de diversas enfermedades de la piel. El extracto de diclorometano-metanol de las partes aéreas de esta especie mostró actividad inhibitoria de la proliferación de ciertas células cancerosas humanas. Lupeol (1), lupenona (2), sitostenona (3), β-sitosterol (4), estigmasterol (5), β-D-glucopiranósido de sitosterilo (6) y el diterpeno relativamente raro tonantzitlolona A (7) fueron caracterizados de este extracto. El análisis estructural de la tonantzitlolona A (7) permitió la reasignación de las señales de RMN 1H de H-12α y H-12β, y de H-13α y H-13β. La actividad citotóxica de los compuestos 1-3, 6 y 7 fue evaluada frente a las líneas celulares cancerosas selectas. Los compuestos 3, 6 y 7 mostraron actividad clara contra K562 (leucemia). Este es el primer reporte sobre los constituyentes químicos de S. macrocarpum, encontrando que esta especie constituye una fuente adicional de tonantzitlolona A. El compuesto 7 ha sido aislado de los géneros Stillingia, Sebastiania y Sapium, los cuales pertenecen a la subtribu Hippomaninae de la familia Euphorbiaceae.

The inadequate treatments given to the served waste water which are disposal to the rivers and sea coast are the major sources of faecal Microorganisms and enteric bacterial pathogens. They are among the most serious effects of water pollution bringing risks on public health. None of the current methods for detection of pathogens offer real-time on site solutions, are capable of delivering a simple visual detection signal, or can be easily instrumented as an indicator of the presence of a pathogen in water. The use of lipid vesicles incorporating Polydiacetylenes (PDAs) for the development of biosensors for “real-time” detection of pathogens has become an alternative, due to its potential for simple colorimetric response against harmful environmental effectors. However, its actual application in the field has been complicated because lipid vesicles are unable to respond specifically to environmental changes. In this paper, we report several experimental trials leading to improved response in the detection of flagellated pathogens in drinking water. Chromatic biomimetic membranes of TRCDA/DMPC and TRCDA/DMPC/Tryptophan were used in agar and liquid media, which were challenged with different amounts of Escherichia coli and Salmonella typhimurium. In addition, the effect of some divalent cations on the interaction with vesicles TRCDA/DMPC was investigated. The results indicated an improvement in the response times, both visually and quantitatively, through the use of TRIS-EDTA and proper growing conditions for E. coli and Salmonella. With the application of both conditions, it was possible by incubation at 35ºC to promote bacterial growth, therefore avoiding a dramatic effect on the colour change over control samples which may invalidate the test. Our experiments indicated that the minimum bacterial concentration necessary to produce the transition from blue to red on the vesicles as biosensor approaches 10(8) CFU/ml within 4 hrs, faster than traditional methods such as MPN or plate count agar. We present here incubations of samples of contaminated water at 35ºC, in agar plates containing chromatic biomimetic membranes of TRCDA/DMPC. A measurable colour transition is obtained within a reaction time of four hrs, which compares favourably with detection times between seven to 24 hrs corresponding to available tests.

Chemical investigation of aerial parts of Schkuhria pinnata var wislizeni (Asteraceae) allowed the characterization of the sesquiterpene lactones 1, 2 and 5, the flavonoids 3 and 4, and the acyl phenyl propanoids 10 and 11. Structure 2, named dischkuhriolin, was confirmed as a Diels Alder adduct of 1 as dienophile and a guaianolide as diene. Spectroscopic analysis of 5 and its diacetyl derivative allowed the structural correction of compounds previously reported from Schkuhria. 2, 10 and 11 are new natural compounds. Biological assays indicated that the mixture 10 + 11 showed antioxidant activity expressed as inhibition of AAPH-induced damage in rat pancreatic homogenate.

La investigación química de las partes aéreas de Schkuhria pinnata var wislizeni (Asteraceae) permitió la caracterización de las lactonas sesquiterpénicas 1, 2 y 5, los favonoides 3 y 4, y los acil fenil propanoides 10 y 11. La estructura 2, nombrada como dieschkuhriolina, fue confirmada como un aducto de Diels Alder de 1 como dienófilo y una guayanólida como dieno. El análisis epectroscópico de 5 permitió la corrección estructural de compuestos reportados previamente de Schkuhria. 2, 10 y 11 son nuevos compuestos naturales. Los ensayos biológicos indicaron que la mezcla 10 + 11 mostró actividad antioxidante expresada como inhibición del daño inducido por HAAP en homogenado pancreático de rata.

Tagitinina A(2), uma 3,10-epoxi-germacrolida-6,7-trans-lactona conhecida e isolada de Tithonia diversifolia foi estudada através de difração de raios-X de monocristal. Verificou-se que a mesma apresenta a configuração relativa 1beta,4alfa,6alfa,7beta,8beta que difere da orientação 1alfa em C(1) proposta originalmente na literatura e que foi determinada pelo método de Horeau. Análise do espectro de ¹H-RMN de 2 em solução de d6-acetona mostra que a molécula mantém a conformação twist-chair-boat (TCB) observada cristalograficamente para o anel de 9 membros. As conformações twist-chair-boat/skew-chair-boat do tipo 3 para anéis de 9 membros saturados e insaturados dentro das 3,10-epoxi-germacrolídas podem ser convertidas à conformação skew-chair-chair (SCC) através de mecanismo de inversão de C(9) do anel. Como resultado dessa mudança conformacional, a orientação de C(1) e de C(8) da unidade oxicarbonila são transformados de diequatorial para diaxial. A estereoquímica relatada para lactonas do tipo 3,10-epoxi-germacrolida e resultados de modelagem utilizando-se DFT B3LYP/6-31g(d) indicam que os átomos C(1) tetraédricos estabilizam conformações TCB/SCB do tipo 3 enquanto que aqueles com geometria trigonal estabilizam a conformação SCC.

Tagitinin A (2), a known 3,10-epoxy-germacrolide-6,7-trans-lactone isolated from Tithonia diversifolia, was investigated by single crystal X-ray diffraction analysis. It was found to have a 1beta,4alpha,6alpha,7beta,8beta relative configuration which differed at C(1) from the 1alpha-orientation originally reported in the literature which was determined by Horeau's Rule. Analysis of the 1H NMR spectrum of 2 shows the molecule to maintain its crystallographically observed twist-chair-boat (TCB) nine-membered ring conformation in acetone-d6 solution. The twist-chair-boat/skew-chair-boat type 3 conformations of saturated/unsaturated nine-membered rings within 3,10-epoxy-germacrolides can be interconverted to the skew-chair-chair (SCC) conformation by means of a C(9) ring atom flip mechanism. As a result of this conformational change, the orientation of the C(1) atom and the C(8)-oxycarbonyl moiety are transformed from diequatorial to diaxial. The reported stereochemistry of 3,10-epoxy-germacrolide lactone structures, and the DFT B3LYP/6-31g(d) modeling findings in this work indicate that tetrahedral C(1) atoms stabilize the TCB/SCB type 3 conformations, while their trigonal counterparts stabilize the SCC conformation.

Tagitinina А(2), uma 3,10-epoxi-germacrolida-6,7-trans-lactona conhecida e isolada de Tithonia diversifolia foi estudada através de difração de raios-X de monocristal. Verificou-se que a mesma apresenta a configuração relativa 1β,4α,6α,7β,8β que difere da orientação 1α em C(1) proposta originalmente na literatura e que foi determinada pelo método de Horeau. Análise do espectro de ¹H-RMN de 2 em solução de d6-acetona mostra que a molécula mantém a conformação twist-chair-boat (TCB) observada cristalograficamente para o anel de 9 membros. As conformações twist-chair-boat/skew-chair-boat do tipo 3 para anéis de 9 membros saturados e insaturados dentro das 3,10-epoxi-germacrolídas podem ser convertidas à conformação skew-chair-chair (SCC) através de mecanismo de inversão de C(9) do anel. Como resultado dessa mudança conformacional, a orientação de C(1) e de C(8) da unidade oxicarbonila são transformados de diequatorial para diaxial. A estereoquímica relatada para lactonas do tipo 3,10-epoxi-germacrolida e resultados de modelagem utilizando-se DFT B3LYP/6-31g(d) indicam que os átomos C(1) tetraédricos estabilizam conformações TCB/SCB do tipo 3 enquanto que aqueles com geometria trigonal estabilizam a conformação SCC.

Tagitinin A (2), a known 3,10-epoxy-germacrolide-6,7-trans-lactone isolated from Tithonia diversifolia, was investigated by single crystal X-ray diffraction analysis. It was found to have a 1β,4α,6α,7β,8β relative configuration which differed at C(1) from the 1α-orientation originally reported in the literature which was determined by Horeau's Rule. Analysis of the 1H NMR spectrum of 2 shows the molecule to maintain its crystallographically observed twist-chair-boat (TCB) nine-membered ring conformation in acetone-d6 solution. The twist-chair-boat/skew-chair-boat type 3 conformations of saturated/unsaturated nine-membered rings within 3,10-epoxy-germacrolides can be interconverted to the skew-chair-chair (SCC) conformation by means of a C(9) ring atom flip mechanism. As a result of this conformational change, the orientation of the C(1) atom and the C(8)-oxycarbonyl moiety are transformed from diequatorial to diaxial. The reported stereochemistry of 3,10-epoxy-germacrolide lactone structures, and the DFT B3LYP/6-31g(d) modeling findings in this work indicate that tetrahedral C(1) atoms stabilize the TCB/SCB type 3 conformations, while their trigonal counterparts stabilize the SCC conformation.

A conformational analysis of the title compound in solution is described. Results show that the preferred conformation is not the one expected from steric considerations. Change of the solvent from CDCl3 to benzene-d6 had no significant effect on the equilibrium.

Se describe el análisis conformacional del compuesto nombrado en el título. Los resultados muestran que la conformación preferida no es la esperada a partir de consideraciones estéricas. El cambio de disolvente de CDCl3 a benceno-d6 no tuvo efecto significativo en el equilibrio.

Several methods for accurate measuring coupling constants are shown. Coupling constants are measured by modified J doubling to simplify and facilitate complex multiplet interpretation. Small coupling constants are measured when they are immersed in the line width for borneol signals. Coupling constants of azo naphtols are measured when a proton, methyl and methoxy groups are interchanged in the molecule. It is shown that modified J doubling has ± 0.03 Hz of accuracy in favorable cases

Se muestran diferentes métodos desarrollados para medir en forma precisa las constantes de acoplamiento. Se determinan constantes de acoplamiento mediante el método modificado de duplicación de J para simplificar y facilitar la interpretación de multipletes complejos. Se miden constantes de acoplamiento que se encuentran inmersas dentro del ancho de la señal del borneol. Se comparan las constantes de acoplamiento en azo naftoles cuando se intercambian un protón, un metilo y un metoxilo. Se muestra que el método modificado de duplicación de J tiene una precisión de ± 0.03 Hz en las constantes de acoplamiento medidas.