Steroidal Saponins and Cell Death in Cancer

Steroidal saponins are natural glycosidic compounds of amphiphilic character. Their diverse biological activities are directly related to the variability of their structural constitutive frameworks, aglycones, and sugars. Several studies have demonstrated the therapeutic potential of steroidal saponins by their capacity to induce programmed cell death in different tumor cell lines. The process of cell death is required to maintain cellular and tissular homeostasis; it has been established that disturbances in the balance between cellular proliferation and cell death lead to several pathologies, including cancer. The antitumor activity of steroidal saponins has been intensely studied allowing elucidation of their different molecular mechanisms of action; this knowledge is crucial to the establishment of new therapeutic strategies against cancer

Westphalen's diol diacetate: 19(10→5)-abeo-5β-cholest-9-ene-3β,6β-diyl diacetate

The structure of the title steroid [alternative name: 3,6- diacetoxy-5-methyl-19-norcholest-9(10)-ene], C31H50O4, confirms the generally accepted mechanism for the rearrangement of a cholestan-5�-ol derivative reported a century ago by Westphalen. The methyl group at position 10 of the starting material migrates to position 5 in the steroidal nucleus, while a 9 bond is formed, as indicated by the C C bond length of 1.347 (4)

(E)-(25S)-23-Acetyl-5β-furost-22-ene-3β,26-diol

The title steroid, C29H46O4, is a furostene derivative with a C=C double-bond length of 1.353 (3) Å and an E configuration. The side chain is oriented toward the α face of the A–E steroidal nucleus and presents a disordered terminal CH2—OH group [occupancies for resolved sites are 0.591 (9) and 0.409 (9)]. The methyl group at C20 attached to ring E is also oriented toward the α face, avoiding steric hindrance with the carbonyl O atom of the acetyl group. The furostene and acetyl functionalities form an α,β-unsaturated ketone system, with an s-cis configuration. All hydr­oxy and carbonyl groups are involved in weak inter­molecular hydrogen bonds. The absolute configuration was assigned from the synthesis

Estrategias de marketing e internacionalización de las MYPES agrícolas productoras de cereales andinos de la provincia de Jauja, Junín, 2020

La presente investigación tuvo como objetivo determinar de qué manera las estrategias de marketing influyen en la internacionalización de las MYPES agrícolas productoras de cereales andinos de la provincia de Jauja, 2020. La metodología tuvo un enfoque cuantitativo, con una población de 20 directivos de cada una de las Mypes teniendo una muestra censal de 20 directivos de cada una de las Mypes. La técnica empleada fue la encuesta y el instrumento utilizado el cuestionario, conformado por 18 ítems por cada variable que fue debidamente validado por tres expertos, para luego demostrar la confiabilidad mediante el Alfa de Cronbach. Los resultados obtenidos fueron de un coeficiente ,629 con una Bilateral de ,003 < ,05 teniendo la conclusión de que si existe relación entre las estrategias de marketing e internacionalización. La recomendación que se le da a la asociación es que realice capacitaciones en cómo mejorar las estrategias de cliente, producto y comunicación y distribución, de no llevarlas a cabo y no aprovechar las dimensiones de estrategias de marketing, la asociación corre el riesgo de seguir vendiéndolos a empresas terceras que les compran cómodo sus productos y venden caro al exterior, reduciendo su ganancia, esfuerzo y bienestar económico

(20S,2′′S)-20-[4′-(3′′-Hydroxy-2′′-methyl­prop­yl)-3′-methylisoxazol-5-yl]-5β-preg­nan-3β,16β-diol

The title steroidal compound, C29H47NO4, was prepared in a one-pot reaction starting from a sarsasapogenin derivative of known configuration. The isoxazole heterocycle is oriented towards the α face of the steroid nucleus and, although fully functionalized on C atoms, does not provoke steric hindrance with the adjacent D ring. The absolute configuration observed for chiral centers is as expected, and shows that no epimerization occurred in the precursors. In the crystal, the three OH groups serve as donors for hydrogen bonding with O and N atoms. The isoxazole N atom is involved in O—H⋯N hydrogen bonds, forming chains along [100]. These chains are further connected via O—H⋯O and weak C—H⋯O contacts, giving rise to a three-dimensional supra­molecular network

The zwitterion (23′E)-(23R,25S)-23-[1-(oxidoiminio)eth­yl]-5β-spiro­stan-3β-yl acetate

The title steroidal compound, C31H49NO5, resulted from the selective oximation of (23R)-23-acetyl­sarsasapogenin acetate. One- and two-dimensional 1H and 13C NMR spectra, as well as IR data, are in agreement with the presence of a ketoxime group at C-23. However, recrystallization in slightly acidic media affords the title compound in the rare zwitterionic oxime form, as a consequence of migration of the hydr­oxy H atom to the N atom in the oxime group. This H atom is clearly detected and its position was refined from X-ray data. The geometry for the C=N+(H)—O− group features long C=N and short N—O bond lengths compared to non-zwitterionic oximes. The ketoxime is stabilized with the E configuration, avoiding steric hindrance between the oxime O atom and H atom at C-23. The sum of the angles around the oxime N atom is 359.6°, giving a planar configuration for that atom, as expected for sp 2 hybridization

Inversión extranjera directa y medio ambiente

En el presente trabajo se analiza la literatura referente a la relación entre la inversión extranjera directa y el medio ambiente, en distintos aspectos; asimismo se revisan algunos instrumentos de política ambiental que los gobiernos implementan para coordinar de manera integral el desarrollo económico. Finalmente, se estudia lo que resulta de la aplicación de tales controles ambientales en el contexto de la ied, a través de modelos teóricos contemporáneos