PROCYANIDIN DIMERS INTERACTION WITH PORCINE PANCREATIC LIPASE

LARRAURI, M; NAPOTE, V; MOSSE, JUANA I.; GALLEANO, M

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencia; 2017

The aim of this work was to study the effect of procyanidin dimers enriched fractions from peanuts skins on pancreatic porcine lipase (PPL) activity and characterize this interaction. Extracts were obtained from skin peanuts (type Runner from Argentina, crop 2012) subjected to blanching (90ºC, 10 min), extracted with ethanol-water (70:30 v/v) following by an ethyl acetate extraction to obtain three fractions: purple (PF), brown (BF) and yellow (YF). Interaction with PPL was studied in terms of enzymatic activity and quenching of fluorescence. Enzymatic activity was tested by monitoring the cleavage of 1,2-O-dilauryl-rac-glycerol-3-glutaric acid (6-methyresorufin) ester to produce methylresorufin previous incubation of PPL with 0?2.5 mg/ml of fractions. Orlistat and epigallocatechin gallate (EGCG) were used as positive controls. PPL inhibition order was YF ≈ BF > PF with IC50 of 1.0±0.1 mg/ml, 1.2±0.1 mg/ml and ˃2 mg/ml, respectively. Quenching of fluorescence (λexc= 295 nm) showed a decreased in Intensity without changes in the maximum peak position, suggesting that the microenvironment of the tryptophan residues is not changed. Data obtained from double logarithmic Stern-Volmer equation was applied to calculate binding constants of YF and BF at different temperatures obtaining the thermodynamic parameters. The binding process was spontaneous (ΔG at 298K = -22.0 and -20.8 kJ/mol for YF and BF, respectively), endothermic (ΔH=13.7 and 39.5 kJ/mol for YF and BF, respectively) and with an increase of entropy (ΔS=121 and 203 J/K mol for YF and BF, respectively). Based on the fractions composition, analyzed by HPLC-ESI-MS/MS, the inhibitory effect was associated to the presence of procyanidin dimers type A, and in a less extent to procyanidin dimers type B. Experiments with purified procyanidin dimers A1, B1 and B2 confirm the results.These results suggest that compounds isolated from peanut skin can be a useful food ingredient with the potentiality of decrease fat absorption in humans.