Front cover: Cocoa Shell Aqueous Phenolic Extract Preserves Mitochondrial Function and Insulin Sensitivity by Attenuating Inflammation between Macrophages and Adipocytes In Vitro

The cocoa shell is a by-product that may be revalorized as a source of bioactive compounds to prevent chronic cardiometabolic diseases. This study aimed to investigate the phytochemicals from the cocoa shell as targeted compounds for activating fibroblast growth factor 21 (FGF21) signaling and regulating non-alcoholic fatty liver disease (NAFLD)-related biomarkers linked to oxidative stress, mitochondrial function, and metabolism in hepatocytes. HepG2 cells treated with palmitic acid (PA, 500 µmol L−1) were used in an NAFLD cell model. Phytochemicals from the cocoa shell (50 µmol L−1) and an aqueous extract (CAE, 100 µg mL−1) enhanced ERK1/2 phosphorylation (1.7- to 3.3-fold) and FGF21 release (1.4- to 3.4-fold) via PPARα activation. Oxidative stress markers were reduced though Nrf-2 regulation. Mitochondrial function (mitochondrial respiration and ATP production) was protected by the PGC-1α pathway modulation. Cocoa shell phytochemicals reduced lipid accumulation (53–115%) and fatty acid synthase activity (59–93%) and prompted CPT-1 activity. Glucose uptake and glucokinase activity were enhanced, whereas glucose production and phosphoenolpyruvate carboxykinase activity were diminished. The increase in the phosphorylation of the insulin receptor, AKT, AMPKα, mTOR, and ERK1/2 conduced to the regulation of hepatic mitochondrial function and energy metabolism. For the first time, the cocoa shell phytochemicals are proved to modulate FGF21 signaling. Results demonstrate the in vitro preventive effect of the phytochemicals from the cocoa shell on NAFLD.

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Cocoa Shell Phenolic Compounds Preserve Mitochondrial Function and Insulin Sensitivity in Adipocytes by Attenuating Their Inflammatory Interplay with Macrophages (FS15-06-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz031.fs15-06-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Miguel Rebollo-Hernanz ◽

Qiaozhi Zhang ◽

Yolanda Aguilera ◽

Maria Angeles Martin-Cabrejas ◽

Elvira Gonzalez de Mejia

Keyword(s):

Insulin Sensitivity ◽

Phenolic Compounds ◽

Insulin Receptor ◽

Mitochondrial Function ◽

Glucose Transporter ◽

Serine Phosphorylation ◽

Peroxisome Proliferator ◽

United States Department ◽

Raw264.7 Macrophages ◽

Cocoa Shell

Abstract Objectives The objective was to evaluate the effect of an aqueous phenolic extract from cocoa shell (CAE) and its main phenolic compounds to prevent the adipogenesis-induced loss of mitochondrial function and insulin sensitivity, targeting the inflammatory interplay macrophages-adipocytes in vitro. Methods CAE and its main phenolic compounds (protocatechuic acid, procyanidin B2, and epicatechin) were tested in cell culture of RAW264.7 macrophages and 3T3-L1 mature adipocytes. Macrophages were stimulated with lipopolysaccharide (LPS, 1 µg/mL). Adipocytes were treated with the conditioned media (CM) from LPS-stimulated macrophages. Biomarkers for inflammation, mitochondrial function, and insulin sensitivity were determined after 24 h co-treatment with CAE and LPS/CM using chemical and immunochemical techniques. Results LPS-stimulated macrophages showed reduced inducible nitric oxide synthase and cyclooxygenase-2 expression and lowered NO and pro-inflammatory cytokines release when treated with CAE and pure phenolics. Inflammatory crosstalk created by stimulating adipocytes with CM was arrested; CAE diminished tumor necrosis factor-α (67%, p < 0.05) and highly promoted adiponectin secretion (12.3-fold, p < 0.05). Mitochondrial function, measured by reactive oxygen species production, mitochondrial content, and activity, was preserved in CM-treated adipocytes through up-regulating peroxisome proliferator-activated receptor gamma coactivator 1-α expression (46%, p < 0.05). Significant (p < 0.05) increases in insulin receptor (9-fold, p < 0.05), phosphoinositide 3-kinase (3-fold, p < 0.05), protein kinase B (4-fold, p < 0.05) phosphorylation and a decrease in insulin receptor substrate 1 serine phosphorylation induced increased glucose uptake (34%, p < 0.05) and glucose transporter 4 translocation (14-fold, p < 0.05) in CM-induced adipocytes. Conclusions Cocoa shell extract polyphenols reduced macrophages-adipocytes inflammatory interaction preventing mitochondrial dysfunction and insulin resistance. For the first time, cocoa shell aqueous extract showed a positive effect on adipogenesis and inflammation-related disorders. Funding Sources Universidad Autónoma de Madrid-Banco Santander, United States Department of Agriculture-National Institute of Food and Agriculture-HATCH, and the Spanish Ministry of Science and Innovation.

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Phytochemicals from Cocoa Shell Protect Mitochondrial Function and Alleviate Oxidative Stress in Hepatocytes via Regulation of ERK and PI3K-AKT Pathways

Medical Sciences Forum ◽

10.3390/msf2021002025 ◽

2021 ◽

Vol 2 (1) ◽

pp. 25

Author(s):

Miguel Rebollo-Hernanz ◽

Yolanda Aguilera ◽

Maria A. Martin-Cabrejas ◽

Elvira Gonzalez de Mejia

Keyword(s):

Oxidative Stress ◽

Mitochondrial Dysfunction ◽

Aqueous Extract ◽

Mitochondrial Function ◽

Nonalcoholic Fatty Liver ◽

Atp Production ◽

Mitochondrial Superoxide ◽

Cocoa Shell ◽

The Impact

This research aimed to assess the impact of an aqueous extract from the cocoa shell and its major phytochemicals on preventing oxidative stress and mitochondrial dysfunction in hepatocytes using an in vitro model of nonalcoholic fatty liver disease (NAFLD). The phytochemicals from cocoa shell were extracted using water and characterized by UPLC-MS/MS analysis. HepG2 cells were cotreated with either the aqueous extract from cocoa shell (CAE, 20–100 µg mL−1) or 10–50 µmol L−1 of pure theobromine, protocatechuic acid, procyanidin B2, epicatechin, and catechin in the presence or absence of palmitic acid (PA, 500 µmol L−1) to mimic NAFLD conditions in vitro. Biomarkers of mitochondrial function and oxidative stress were evaluated 24 h after the cotreatment in cell supernatants and lysates using chemical, biochemical, and immunochemical techniques. CAE and the phytochemicals therein significantly (p < 0.05) protected mitochondrial content (15–100%) and preserved mitochondrial function, promoting O2 consumption (1.2- to 1.8-fold) and ATP production (1.3- to 2.1-fold). Phytochemicals from cocoa shell significantly (p < 0.05) decreased PA-triggered oxidative stress. The mitochondrial membrane potential was maintained (62–100%), and the production of mitochondrial superoxide (26–100%) and total ROS (17–100%) was abrogated. CAE significantly (p < 0.05) modulated cell signaling pathways associated with ROS production and mitochondrial dysfunction, including an increase in the phosphorylation of ERK1/2 (2.8-fold), protein kinase B (AKT) (2.8-fold), GSK3 (2.3-fold), Raf-1 (1.9-fold), and mTOR (1.7-fold). In conclusion, results suggested that the cocoa shell’s phytochemicals could protect mitochondrial liver function and alleviate oxidative stress by modulating key pathways involved in their regulation.

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