Proteinaceous Pancreatic Lipase Inhibitor from the Seed of Litchi chinensis

Sveeta V Mhatre,Raman P Yadav,Amita A Bhagit

doi:10.17113/ftb.57.01.19.5909

Abstract

SUMMARYA study of the pancreatic lipase inhibitory activity of a protein from the seed of Litchi chinensis was carried out. Protein was isolated by 70% ammonium sulphate precipitation followed by dialysis. Lipase inhibitory activity of the protein was evaluated using both synthetic (p-nitrophenyl palmitate) and natural (olive oil) substrates. Protein at the final concentration of 100 µg/mL was able to inhibit 68.2% pancreatic lipase on synthetic substrate and 60.0% on natural substrate. Proteinaceous nature of the inhibitor was determined using trypsinization assay. Pancreatic lipase inhibitory protein was sensitive to 0.05% trypsin treatment with the loss of 61.9% activity. IC50 of this proteinaceous pancreatic lipase inhibitor was 73.1 µg/mL using synthetic substrate. This inhibitory protein was sensitive to pH, with the highest inhibitory activity at pH=8.0 and the lowest at pH=3.0. Protein was further analyzed using 10% non-reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and, interestingly, it showed the presence of a single band of (61±2) kDa when stained with Coomassie brilliant blue. The isolated protein was finally crystallized to see its homogeneity by batch crystallization method. Crystals were well formed with distinct edges. The isolated protein showed good pancreatic lipase inhibitory activity.

Highlights

Obesity is a global health concern, widely recognised as the largest and fastest growing public health problem in the developed and developing world associated with high morbidity and mortality [1]
The present study focuses on the new proteinaceous pancreatic lipase inhibitor isolated from the seeds of Litchi chinensis fruit and its potential in the development of anti-obesity agents
Litchi chinensis seed protein at 100 μg/mL exhibited 68.2 % of pancreatic lipase inhibition in synthetic substrate. This indicates that Litchi chinensis is a potential source of pancreatic lipase inhibitor

Summary

Introduction

Obesity is a global health concern, widely recognised as the largest and fastest growing public health problem in the developed and developing world associated with high morbidity and mortality [1]. Pancreatic lipase is a prime lipid-digesting enzyme that removes fatty acids from the α and α, positions of dietary triacylglycerols, yielding lipolytic product β-monoglyceride and saturated and polyunsaturated long-chain fatty acids. Inhibition of pancreatic lipase is an interesting advancement towards the discovery of potent anti-obesity agents for the management of obesity [4,5]. Orlistat is well known to inhibit pancreatic and gastrointestinal lipases and is capable of reducing dietary fat absorption up to 30 % [6]. Natural products provide an ample scope for the discovery of pancreatic lipase inhibitors that can perhaps be developed into anti-obesity drugs [9,10,11]. The existence of plant protein that inhibits the activity of mammalian enzymes has long been known.

Methods

Results

Conclusion