Cocoa bean (Theobroma cacao L.) phenolic extracts as PTP1B inhibitors, hepatic HepG2 and pancreatic β-TC3 cell cytoprotective agents and their influence on oxidative stress in rats

Abstract

Recently attention has been focused on cocoa beans that are the primary raw material used for the preparation of cocoa powder or chocolate as valuable source of bioactive substances with high antioxidant potential and well documented beneficial health properties, including prevention and treatment of type 2 diabetes. The ability of phenolic compounds to inhibit the activity of enzyme hydrolyzing carbohydrates is already quite well studied, however the anti-obesity and antidiabetic activity of cocoa extracts obtained from roasted beans as cytoprotective agents or insulin signaling regulators is not known. In the present study for the first time compounds of raw and roasted cocoa bean of Forastero variety phenolic extracts were separated and purificated via centrifugal partition chromatography (CPC) technique. Obtained preparations were in vitro investigated in terms of the PTP1B inhibition and cytoprotective activity against oxidative stress using human hepatoma HepG2 and mouse pancreatic β-TC3 cell lines. Additionally the influence of preparations on fat tissue and antioxidant properties in vivo on rat animal model was studied. Taking into account obtained results it can be concluded that cocoa phytochemicals, including pigment's fraction of roasted beans with melanoidins, are potential modulators of insulin signaling, protect beta and hepatic cells against cellular damage induced by excessive oxidative stress. This study for the first time reports potential anti-obesity properties of roasted cocoa bean extract rich in MRP, which makes this extract as promising candidate for diabetes prevention and associated metabolic disorder.