Radical Scavenging and Cellular Antioxidant Activity of the Cocoa Shell Phenolic Compounds after Simulated Digestion

Limitations and Challenges of Antioxidant Therapy

Our bodies are constantly exposed to or producing free radicals nearly on a daily basis. These highly reactive molecules are generated through a variety of internal and external processes and pathways within the body. If these free radicals are not neutralized by antioxidants, they can lead to a state of oxidative stress, which has been linked to a wide range of severe and debilitating disorders affecting various systems in the human body. This involves neurodegenerative diseases, diabetes, atherosclerosis, fatty liver, inflammation, and aging. Thankfully, the human body is armed with a repertoire of powerful antioxidants with different natures and modes of action. The recent decades witnessed the publication of enormous papers proving antioxidant activity of a novel synthesized compound, plant extract, or a purified drug in vitro, in vivo, and even on human beings. However, the efficacy of antioxidant therapies in clinical trials, including selenium, vitamin C, vitamin E, and vitamin A, has been notably inconsistent. This inconsistency can be primarily ascribed to different factors related to the nature of free radical generation, purpose and the specific type of therapy employed, and the intricate oxidative stress connected network, among others. Collectively, these factors will be explored in this review article to decipher the observed shortcomings in the application of antioxidant therapies within clinical settings.

Investigating the Optimal Membrane-Based Separation of Cynaroside From Peony Seed Meals and Assessing Its Biomedical Implications

This comprehensive study focused on evaluating and selecting seven distinct commercial membranes to develop BTESE/PA membranes. This method effectively facilitated the extraction of cynaroside from the complex composition of peony seed meal. We subsequently conducted a thorough investigation into its biological properties. These findings establish a robust foundation for future research and the development of related products. The peak concentration achieved by peony seed meal filtration (PSMF) was 234.84 ± 1.17 μg/mL. Among the commercial membranes evaluated, the PA membrane exhibited superior separation capabilities, leading to its selection for BTESE loading. Compared with BTESE treated with HCl and NH3, the HCl variant, once incorporated into the BTESE/PA membrane, enhanced cynaroside separation, achieving an impressive 90.23% recovery rate. A comprehensive investigation of the biological effects of cynaroside revealed its crucial antioxidant role, especially in SOD binding. Additionally, cynaroside has the potential to induce apoptosis in K562 cells through interactions with BCL-2 and CDK-2 enzymes. Pharmacophore screening revealed the affinity of cynaroside for the PDE5A, TNKS2, and DAPK1 proteins, suggesting that it has diverse potential applications.

Transformations of phenolic compounds in cocoa shell during in vitro colonic fermentation

Cocoa shell is a by-product generated by the cocoa processing industry, notable for its high content of phenolic compounds and methylxanthines, and recognized for their biological properties. The majority of cocoa phenolic compounds are not absorbed in the small intestine and reach the colon, where they can be catabolized by the gut microbiota, influencing their bioavailability and bioactivity. This research aimed to study the changes that phenolic compounds from cocoa shell flour (CSF) and extract (CSE) undergo during colonic fermentation after gastrointestinal digestion, using an in vitro model and a targeted metabolomics approach. A decrease in the concentration of most parental phenolic compounds was observed, with a simultaneous increase in phenyl-γ-valerolactones, phenylvaleric acids, and phenylpropanoic acids. Benzoic acids, phenylpropanoic acids, phenylacetic acids, and benzaldehydes were the compounds found in the highest concentrations. Additionally, phenolic compounds in CSF were metabolized more slowly than those in CSE. This may be due to the matrix effect that protects the compounds from degradation during colonic fermentation. These findings further support the potential of cocoa shells as a food ingredient rich in phenolic compounds and bioavailable metabolites, which may exert beneficial effects in the colon and at the systemic level.

Cocoa shell ingredients improve their lipid-lowering properties under simulated digestion: In vitro and HepG2 cells study

Cocoa (Theobroma cacao) shell, the main by-product of cocoa industry, is associated with the regulation of several biomarkers of metabolic syndrome. However, there is little information about the digestion effect on the physiological properties of cocoa shell. The aim of this study was to assess the impact of a standardized in vitro digestion protocol on the hypolipidemic capacity of two cocoa shell ingredients, a flour (CSF) and an aqueous extract (CSE), through the evaluation of their in vitro hypolipidemic properties and lipid-lowering effects in HepG2 cells. CSF and CSE digested fractions increased their capacity to bind primary bile acids (16-88 %) and inhibit lipase activity (41-100 %), while their ability to bind secondary bile acids (33-42 %) was maintained. Likewise, the digested fractions of cocoa shell ingredients reduced the solubility of the cholesterol micelles (35-97 %) and inhibited the hydroxymethylglutaryl-Co-enzyme A reductase (HMGCR) activity (18-100 %). The hypolipidemic properties of non-digested fractions further enhanced the CSF potential to decrease lipid absorption. Cocoa shell ingredients demonstrated lipid-lowering properties after simulated digestion by effectively reducing the accumulation of intracellular lipids (78-122 %), triacylglycerides (60-90 %), and cholesterol (100 %) induced by palmitic acid in hepatic cells. These results were confirmed by their ability to stimulate lipolysis, reducing the increase in lipase activity (28-78 %) and increasing glycerol release (27-80 %) with respect to palmitic acid treated cells, and inhibiting HMGCR activity. Phenolic compounds and dietary fiber are significantly associated to the observed hypolipidemic effects of cocoa shell ingredients. These findings demonstrated the potential efficacy of CSF and CSE in reducing lipid absorption and reversing its hepatic accumulation. Hence, these cocoa shell ingredients might prevent diseases related to lipid accumulation by improving overall health status.

Exploring the Physicochemical Characteristics of Marine Protein Hydrolysates and the Impact of In Vitro Gastrointestinal Digestion on Their Bioactivity

Fish protein hydrolysates (FPHs) were obtained from different fish sources using a combination of microbial enzymes. The industrially produced FPHs from blue whiting (Micromesistius poutassou) and sprat (Sprattus sprattus) were compared to freeze-dried FPHs generated in-house from hake (Merluccius merluccius) and mackerel (Scomber scombrus) in terms of their physicochemical composition and functionality. Significant differences (p < 0.05) were observed in the protein, moisture, and ash contents of the FPHs, with the majority having high levels of protein (73.24-89.31%). Fractions that were more extensively hydrolysed exhibited a high solubility index (74.05-98.99%) at different pHs. Blue whiting protein hydrolysate-B (BWPH-B) had the highest foaming capacity at pH 4 (146.98 ± 4.28%) and foam stability over 5 min (90-100%) at pH 4, 6, and 8. The emulsifying capacity ranged from 61.11-108.90 m2/g, while emulsion stability was 37.82-76.99% at 0.5% (w/v) concentration. In terms of peptide bioactivity, sprat protein hydrolysate (SPH) had the strongest overall reducing power. The highest Cu2+ chelating activity was exhibited by hake protein hydrolysate (HPH) and mackerel protein hydrolysate (MPH), with IC50 values of 0.66 and 0.78 mg protein/mL, respectively, while blue whiting protein hydrolysate-A (BWPH-A) had the highest activity against Fe2+ (IC50 = 1.89 mg protein/mL). SPH scavenged DPPH and ABTS radicals best with IC50 values of 0.73 and 2.76 mg protein/mL, respectively. All FPHs displayed noteworthy scavenging activity against hydroxyl radicals, with IC50 values ranging from 0.48-3.46 mg protein/mL. SPH and MPH showed the highest scavenging potential against superoxide radicals with IC50 values of 1.75 and 2.53 mg protein/mL and against hydrogen peroxide with 2.22 and 3.66 mg protein/mL, respectively. While inhibition of α-glucosidase was not observed, the IC50 values against α-amylase ranged from 8.81-18.42 mg protein/mL, with SPH displaying the highest activity. The stability of FPHs following simulated gastrointestinal digestion (SGID) showed an irregular trend. Overall, the findings suggest that marine-derived protein hydrolysates may serve as good sources of natural nutraceuticals with antioxidant and antidiabetic properties.

Exploring the potential of phenolic compounds from the coffee pulp in preventing cellular oxidative stress after in vitro digestion

The coffee pulp, a by-product of the coffee industry, contains a high concentration of phenolic compounds and caffeine. Simulated gastrointestinal digestion may influence these active compounds' bioaccessibility, bioavailability, and bioactivity. Understanding the impact of the digestive metabolism on the coffee pulp's phenolic composition and its effect on cellular oxidative stress biomarkers is essential. In this study, we evaluated the influence of in vitro gastrointestinal digestion of the coffee pulp flour (CPF) and extract (CPE) on their phenolic profile, radical scavenging capacity, cellular antioxidant activity, and cytoprotective properties in intestinal epithelial (IEC-6) and hepatic (HepG2) cells. The CPF and the CPE contained a high amount of caffeine and phenolic compounds, predominantly phenolic acids (3',4'-dihydroxycinnamoylquinic and 3,4-dihydroxybenzoic acids) and flavonoids (3,3',4',5,7-pentahydroxyflavone derivatives). Simulated digestion resulted in increased antioxidant capacity, and both the CPF and the CPE demonstrated free radical scavenging abilities even after in vitro digestion. The CPF and the CPE did not induce cytotoxicity in intestinal and hepatic cells, and both matrices exhibited the ability to scavenge intracellular reactive oxygen species. The coffee pulp treatments prevented the decrease of glutathione, thiol groups, and superoxide dismutase and catalase enzymatic activities evoked by tert-butyl hydroperoxide elicitation in IEC-6 and HepG2 cells. Our findings suggest that the coffee pulp could be used as a potent food ingredient for preventing cellular oxidative stress due to its high content of antioxidant compounds.

Cocoa Shell Extract Reduces Blood Pressure in Aged Hypertensive Rats via the Cardiovascular Upregulation of Endothelial Nitric Oxide Synthase and Nuclear Factor (Erythroid-Derived 2)-like 2 Protein Expression

Cocoa shell is a by-product of cocoa manufacturing. We obtained an aqueous extract (CSE) rich in polyphenols and methylxanthines with antioxidant and vasodilatory properties. We aimed to evaluate the effects of CSE supplementation in aged hypertensive rats on blood pressure and the mechanism implicated. Eighteen-month-old male and female rats exposed to undernutrition during the fetal period who developed hypertension, with a milder form in females, were used (MUN rats). Systolic blood pressure (SBP; tail-cuff plethysmography) and a blood sample were obtained before (basal) and after CSE supplementation (250 mg/kg; 2 weeks, 5 days/week). Plasma SOD, catalase activity, GSH, carbonyls, and lipid peroxidation were assessed (spectrophotometry). In hearts and aortas from supplemented and non-supplemented age-matched rats, we evaluated the protein expression of SOD-2, catalase, HO-1, UCP-2, total and phosphorylated Nrf2 and e-NOS (Western blot), and aorta media thickness (confocal microscopy). MUN males had higher SBP compared with females, which was reduced via CSE supplementation with a significant difference for group, sex, and interaction effect. After supplementation with plasma, GSH, but not catalase or SOD, was elevated in males and females. Compared with non-supplemented rats, CSE-supplemented males and females exhibited increased aorta e-NOS and Nrf2 protein expression and cardiac phosphorylated-Nrf2, without changes in SOD-2, catalase, HO-1, or UCP-2 in cardiovascular tissues or aorta remodeling. In conclusion, CSE supplementation induces antihypertensive actions related to the upregulation of e-NOS and Nrf2 expression and GSH elevation and a possible direct antioxidant effect of CSE bioactive components. Two weeks of supplementation may be insufficient to increase antioxidant enzyme expression.

Changes in the cocoa shell dietary fiber and phenolic compounds after extrusion determine its functional and physiological properties

The influence of different extrusion conditions on the cocoa shell (CS) dietary fiber, phenolic compounds, and antioxidant and functional properties was evaluated. Extrusion produced losses in the CS dietary fiber (3-26%), especially in the insoluble fraction, being more accentuated at higher temperatures (160 °C) and lower moisture feed (15-20%). The soluble fiber fraction significantly increased at 135 °C because of the solubilization of galactose- and glucose-containing insoluble polysaccharides. The extruded CS treated at 160 °C-25% of feed moisture showed the highest increase of total (27%) and free (58%) phenolic compounds, accompanied by an increase of indirect (10%) and direct (77%) antioxidant capacity. However, more promising results relative to the phenolic compounds' bioaccessibility after in vitro simulated digestion were observed for 135°C-15% of feed moisture extrusion conditions. The CS' physicochemical and techno-functional properties were affected by extrusion, producing extrudates with higher bulk density, a diminished capacity to hold oil (22-28%) and water (18-65%), and improved swelling properties (14-35%). The extruded CS exhibited increased glucose adsorption capacity (up to 2.1-fold, at 135 °C-15% of feed moisture) and α-amylase in vitro inhibitory capacity (29-54%), accompanied by an increase in their glucose diffusion delaying ability (73-91%) and their starch digestion retardation capacity (up to 2.8-fold, at 135 °C-15% of feed moisture). Moreover, the extruded CS preserved its cholesterol and bile salts binding capacity and pancreatic lipase inhibitory properties. These findings generated knowledge of the CS valorization through extrusion to produce foods rich in dietary fiber with improved health-promoting properties due to the extrusion-triggered fiber solubilization.