Abstract Pancreatic lipase is a key enzyme in lipid metabolism. Flavonoids are bioactive compounds obtained from vegetables with big relevance, due to their intrinsic interaction with digestive enzymes. Pancreatic lipase activity was evaluated in the presence of flavonoids, through UV-Vis spectroscopy. All tested flavonoids showed a mixed-type inhibition, except catechin, which showed a uncompetitive inhibition. The best inhibitor was quercetin followed by rutin > luteolin > catechin > hesperetin, with IC50 values of 10.30, 13.50, 14.70, 28.50 and 30.50 µM, respectively. The flavonoids inhibitory capacity was related to structural properties shared between the different flavonoids, such as the hydroxylation at C5, C7 (ring A), C2’ and C3’ (ring B), and the double bond between C2 and C3 (ring C). The inhibition results are in agreement with the extrinsic fluorescence analysis. Molecular docking studies indicated that the interaction between pancreatic lipase and flavonoids was mainly through hydrophobic interactions (pi-stacking). The interactions of all flavonoids, except rutin, occurred at the same enzyme site (subsite 1). Instauration between C2 and C3 was decisive for the arrangement of flavonoids with the enzyme, mainly due to pi-stacking interactions.

Resumen Lipasa pancreática es una enzima clave en el metabolismo de lípidos. Los flavonoides son compuestos bioactivos de gran relevancia debido a sus interacciones con enzimas digestivas. Se evaluó la actividad de lipasa pancreática en presencia de flavonoides. Mediante espectroscopía UV Visible se determinó que el mejor inhibidor fue quercetina, seguido de rutina > luteolina > catequina > hesperetina, con valores de IC50 de 10.30, 13.50, 14.70, 28.50 y 30.50 µM, respectivamente. Todos los flavonoides mostraron una inhibición mixta, excepto catequina que mostró una inhibición acompetitiva. La capacidad inhibitoria de los flavonoides se relacionó con propiedades estructurales compartidas entre los distintos flavonoides, como la hidroxilación en las posiciones C5, C7 (anillo A), C2’ y C3’ (anillo B), y el doble enlace entre C2 y C3 (anillo C). Los resultados de inhibición coincidieron con el análisis de la fluorescencia extrínseca. Los estudios de docking molecular indicaron que la interacción entre lipasa pancreática y los flavonoides fue principalmente mediante interacciones hidrofóbicas (pi-stacking). Las interacciones de todos los flavonoides, excepto rutina, se dieron en el mismo sitio (subsitio 1) de la enzima. La insaturación entre C2 y C3 fue determinante para el acomodo de los flavonoides con la enzima, principalmente por interacciones de pi-stacking.

Abstract Harpin protein was used as an elicitor in green (butterhead) and red (oak leaf type) varieties of hydroponically grown lettuce (Lactuca sativa L.). Its impact on polyphenolic content and antioxidant capacity was evaluated. Harpin protein was sprayed three days before harvesting in concentrations of 45, 60, and 120 mg/L. Green lettuce samples showed a positive response to Harpin by significantly increasing its phenolic content from 12 (control) to 16.43 mg gallic acid equivalents (GAE)/100 g dry weight (DW) (120 mg/L Harpin treatment) which means a 36.9% increase. Chlorogenic acid was the only phenolic compound that increased its concentration after lettuce induction with Harpin treatment. Antioxidant capacity, evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH˙) and ferric reducing antioxidant power (FRAP) methods, also showed a significant increase (46.5 and 64.3%, respectively) in Harpin-treated green lettuce. The red lettuce variety showed none or a negative response to Harpin treatment for all parameters evaluated. These results show that elicitation may be an effective strategy to enhance phenolic content in lettuce varieties.

The main function of the adipocyte is lipid storage when there is a positive energy balance and lipid release when there is and energy deficiency. One characteristic of obesity is an increase in the number and size of adipocytes, which implies pre adipocyte (PAD) differentiation. The adipose tissue (AT) has its origins in the prenatal stage and may continue to expand during adulthood from precursor cells since mature adipocytes cannot multiply by cell division. This study provide updates on the events that occur during the origin and differentiation of PAD, the factors involved in the regulation of adipogenesis and mechanisms that regulate physiological functions of AT.

La principal función de los adipocitos es el almacenamiento de lípidos cuando hay exceso de energía y la movilización de la misma cuando hay deficiencia. Una de las características de la obesidad es el aumento de la cantidad y el tamaño de los adipocitos, lo que implica la diferenciación de preadipocitos (PAD). El tejido adiposo (TA) tiene su origen en la etapa prenatal y puede seguir expandiéndose durante la vida adulta a partir de células precursoras, ya que los adipocitos maduros no pueden multiplicarse por división celular. El presente estudio proveerá información reciente de los eventos que se producen durante el origen y diferenciación de los PAD, así como los factores implicados en la regulación de la adipogénesis y los mecanismos que regulan las funciones fisiológicas del TA.