Chemical characterization of a hypoglycemic extract from Cucurbita ficifolia bouche that induces liver glycogen accumulation in diabetic mice

Background: The aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia, the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit is due to accumulation of liver glycogen in diabetic mice.Materials and Methods: The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&E stain.Results: Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia: p-coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract.Conclusion: Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be elucidated in subsequent studies.Keywords: Cucurbita ficifolia, Cucurbitaceae, liver glycogen, hypoglycemic plants, p-coumaric acid, salicin, p-hydroxybenzoic aci

CHEMICAL CHARACTERIZATION OF A HYPOGLYCEMIC EXTRACT FROM CUCURBITA FICIFOLIA BOUCHE THAT INDUCES LIVER GLYCOGEN ACCUMULATION IN DIABETIC MICE.

Background: The aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia, the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia (C. ficifolia) fruit is due to accumulation of liver glycogen in diabetic mice. Materials and Methods: The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&E stain. Results: Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia: p-coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract. Conclusion: Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be elucidated in subsequent studies

INFLUENCIA DE LA GLICINA SOBRE LA EXPRESION DE ADIPOCINAS DE RATON: ESTUDIO IN VIVO E IN VITRO

Uno de los principales problemas de salud en México es la diabetes mellitus tipo 2 (DT2). La obesidad o el sobrepeso son factores de riesgo para desarrollar DT2. Existe una relación muy importante entre estas patologías ya que se caracterizan por generar un estado de inflamación crónica que se manifiesta como un incremento de marcadores inflamatorios, como el factor de necrosis tumoral tipo alfa (TNF-α), la interleucina 6 (IL-6), la proteína C reactiva y elevación en los niveles plasmáticos del angiotensinógeno, ocasionando el desarrollo de complicaciones vasculares. Particularmente las complicaciones macrovasculares presentes en los estados de obesidad y en los pacientes con DT2. Existen diversas alternativas terapéuticas para el tratamiento y control de estas enfermedades. Se ha demostrado que la glicina, un aminoácido con propiedades antiinflamatorias, disminuye la expresión de IL-6 y TNF-α y aumenta la de IL-10 en cultivos de células de Kupffer. El objetivo de la presente investigación fue determinar el efecto de la glicina sobre la expresión de los genes de las adipocinas IL-6, TNF-α, resistina (proinflamatorias) y adiponectina (antiinflamatoria) en células 3T3-L1 de ratón y sobre las concentraciones plasmáticas de las mismas en ratones obesos. Los experimentos se realizaron en cultivos de fibroblastos de ratón (línea 3T3-L1), los cuales fueron diferenciados a adipocitos y mantenidos bajo condiciones de alta concentración de glucosa durante el proceso de diferenciación; adicionando glicina a dosis de 10 mM. Al finalizar el tratamiento se cuantificaron los niveles de expresión del RNAm de las adipocinas mencionadas. Por otro lado, la glicina se administró durante 30 días (dosis de 0.1 g/Kg en el agua de beber) a un modelo de ratones con obesidad experimental inducida con la administración neonatal de glutamato monosódico (ratón Ob/GMS) a partir de las 14 semanas de edad. Al finalizar el tratamiento se cuantificaron los niveles plasmáticos de las adipocinas. Los resultados muestran que la glicina, además de aumentar significativamente los niveles de la adiponectina, reduce la IL-6 y la resistina (P<0.05), tanto en los niveles de expresión cuantificados por RT-PCR tiempo real como en los niveles plasmáticos de las proteínas. Además, en las células tratadas con glicina se logró detectar disminución significativa en los niveles de expresión de TNF-α (P<0.05). Por lo anterior se puede concluir que la glicina tiene efecto antiinflamatorio, tanto in vitro como in vivo. Con estas evidencias experimentales se pueden plantear nuevas investigaciones referentes al balance energético que se da entre moléculas encargadas de la regulación de citocinas, principalmente aquéllas implicadas en el estado inflamatorio característico de los individuos obesos y pacientes con diabetes tipo 2. Además, es importante destacar el valor terapéutico que la glicina podría tener en el tratamiento y control de los pacientes con DT2 ya que estos resultados apuntan a que se trata de una alternativa útil para controlar el proceso inflamatorio y disminuir el desarrollo de sus complicaciones vasculares