Bioavailability and Bioactivities of Polyphenols Eco Extracts from Coffee Grounds after In Vitro Digestion

Organic and Conventional Coffee Beans, Infusions, and Grounds as a Rich Sources of Phenolic Compounds in Coffees from Different Origins

Coffee is a beverage that contains a high concentration of bioactive compounds, particularly polyphenols. These compounds significantly contribute to the polyphenol intake in the diet and have been shown to have beneficial effects on consumer health. The objective of this research was to conduct a comparative analysis of the polyphenolic composition of coffee beans and infusions obtained from coffee beans sourced from both organic and conventional farming practices while taking into consideration variations in roast intensity and geographical origin. The lyophilized coffee grounds and infusions derived from these grounds were also subjected to analysis. The antioxidant activity was measured by using the radical ABTS, and the quantitative and qualitative analysis of polyphenolic compounds was conducted by HPLC. The conventional coffee samples were richer in chlorogenic acid, catechin, and caffeic acid. However, the coffee beans from organic farming contained more gallic acid, epigallocatechin gallate, and quercetin than those grown conventionally. We did not observe significant differences among the coffee plant production sites in Ethiopia, Sumatra, and Peru, but Peru had the poorest amount of polyphenols when compared to Ethiopia and Sumatra. Coffee infusions prepared from organic coffee beans were characterized by a significantly high sum of identified polyphenols. A higher content of caffeine was observed in the organic coffee bean samples than in the conventional coffee bean samples. Conventional coffee beans were characterized by stronger antioxidant activity than organic beans. Coffees from different parts of the world were characterized by different profiles of polyphenol compounds. Moreover, the coffee beans from Ethiopia were characterized by the highest caffeine content. However, among the different geographical areas of coffee beans, the highest antioxidant activity was detected in the coffee beans from Sumatra. Coffee grounds also have the potential to be used as compounds for the cultivation of horticultural plants, and they can be used as a source of numerous health-promoting compounds in the food and cosmetics industries.

Polyphenols: From Classification to Therapeutic Potential and Bioavailability

Though ubiquitous in nature, polyphenols gained scientific prominence only after the pioneering work of researchers like E. Fischer and K. Freudenberg, who demonstrated their potential beyond traditional applications, such as in the leather industry. Today, these bioactive compounds are recognized for their diverse therapeutic roles, including their use as adjuvants in cancer treatment, cancer prevention, and their anti-inflammatory and antioxidant properties. Additionally, polyphenols have demonstrated benefits in managing obesity, cardiovascular diseases, and neuromodulation. Their synthesis is influenced by environmental and genetic factors, with their concentrations varying based on the intensity of these variables, as well as the stage of ripening. This review provides a comprehensive overview of polyphenols, covering their classification, chemical structures, and bioavailability. The mechanisms influencing bioavailability, bioaccessibility, and bioactivity are explored in detail, alongside an introduction to their bioactive effects and associated metabolic pathways. Specific examples, such as the bioavailability of polyphenols in coffee and various types of onions, are analyzed. Despite their promising biological activities, a significant limitation of polyphenols lies in their inherently low oral bioavailability. However, their systemic circulation and the bioactive by-products formed during digestion present exciting opportunities for further research and application.

Metabolomic monitoring of chicory during in vitro gastrointestinal digestion and correlation with bioactive properties

Chicory, recognized as a functional food, is increasingly becoming the focus of research. This study aimed to investigate the in vitro impact of gastrointestinal digestion on the composition and bioactive properties of chicory decoction. Chicory flour, derived from the roots, was transformed into an aqueous decoction and was subjected to simulated in vitro human gastrointestinal digestion (SGID). For the first time, the influence of the digestive process on specific classes of bioactive molecules was tracked across different digestive compartments (oral, gastric, and intestinal) using a metabolomic approach. Concurrently, the antioxidant, anti-inflammatory, and intestinal hormone regulation effects were assessed before and after SGID. The findings revealed that specific transformations of chlorogenic acid (CGA) and sesquiterpene lactones (STL) during SGID enhanced antioxidant and anti-inflammatory properties post-digestion. Quantitative results demonstrated a significant increase in ROS scavenging capacity and metabolite activity.

Dietary Polyphenols: Review on Chemistry/Sources, Bioavailability/Metabolism, Antioxidant Effects, and Their Role in Disease Management

Polyphenols, as secondary metabolites ubiquitous in plant sources, have emerged as pivotal bioactive compounds with far-reaching implications for human health. Plant polyphenols exhibit direct or indirect associations with biomolecules capable of modulating diverse physiological pathways. Due to their inherent abundance and structural diversity, polyphenols have garnered substantial attention from both the scientific and clinical communities. The review begins by providing an in-depth analysis of the chemical intricacies of polyphenols, shedding light on their structural diversity and the implications of such diversity on their biological activities. Subsequently, an exploration of the dietary origins of polyphenols elucidates the natural plant-based sources that contribute to their global availability. The discussion extends to the bioavailability and metabolism of polyphenols within the human body, unraveling the complex journey from ingestion to systemic effects. A central focus of the review is dedicated to unravelling the antioxidant effects of polyphenols, highlighting their role in combating oxidative stress and associated health conditions. The comprehensive analysis encompasses their impact on diverse health concerns such as hypertension, allergies, aging, and chronic diseases like heart stroke and diabetes. Insights into the global beneficial effects of polyphenols further underscore their potential as preventive and therapeutic agents. This review article critically examines the multifaceted aspects of dietary polyphenols, encompassing their chemistry, dietary origins, bioavailability/metabolism dynamics, and profound antioxidant effects. The synthesis of information presented herein aims to provide a valuable resource for researchers, clinicians, and health enthusiasts, fostering a deeper understanding of the intricate relationship between polyphenols and human health.

In vitro gastrointestinal digestion methods of carbohydrate-rich foods

The trend toward healthier food products has led to an increase in the research of in vitro gastrointestinal digestion methods. Among the most used models, static models are the simplest. Most static models have three stages: oral, gastric, and intestinal, simulating the enzymatic, electrolyte, pH, temperature, and bile salt conditions. The studies that have taken the most notice are those related to antioxidant activity, followed by those dealing with proteins and carbohydrates using most of them static in vitro digestion models. The number of these studies has increased over the years, passing from 45 to 415 in a 10-year period (2012-2023) and showing an interest in knowing the impact of food on human health. Nevertheless, published papers report different methodologies and analytical approaches. This review discusses the similarities and differences between the published static in vitro gastrointestinal digestion methods, with a focus on carbohydrates, finding that the most used protocol is Infogest, but with differences, mainly in the type of enzymes and their activity. Regarding in vitro gastrointestinal digestion of carbohydrates, many of the published studies are related to food and biomacromolecules, being the oral phase the most omitted, while the intestinal phase in the most diverse. Other methodologies to study the intestinal phase have been recommended, but the number of in vitro digestion studies using these methodologies (RSIE and BBMV) is still scarce but could represent a good alternative to analyze carbohydrates foods when combining with Infogest. More studies are required in this area.

Mineral-Enriched Postbiotics: A New Perspective for Microbial Therapy to Prevent and Treat Gut Dysbiosis

Postbiotics are non-viable probiotic preparations that confer a health benefit on the host. In the last years, scientific literature has proved that postbiotics have health-promoting features and technological advantages compared to probiotics, augmenting their full potential application in the food and pharmaceutical industries. The current work comprehensively summarizes the benefits and potential applications of postbiotics and essential mineral-enriched biomass and proposes a new strategy for microbial therapy—mineral-enriched postbiotics. We hypothesize and critically review the relationship between micronutrients (calcium, magnesium, iron, zinc, selenium) and postbiotics with gut microbiota, which has been barely explored yet, and how the new approach could be involved in the gut microbiome modulation to prevent and treat gut dysbiosis. Additionally, the bioactive molecules and minerals from postbiotics could influence the host mineral status, directly or through gut microbiota, which increases the mineral bioavailability. The review increases our understanding of the health improvements of mineral-enriched postbiotics, including antioxidant functions, highlighting their perspective on microbial therapy to prevent and threaten gut-related diseases.

Bioaccessibility and bioactivities of phenolic compounds from roasted coffee beans during in vitro digestion and colonic fermentation

Bioaccessibility and bioactivity of phenolic compounds in coffee beans relate to roasting and digestion process. This study aimed to estimate phenolic content, antioxidant potential, bioaccessibility, and changes in short chain fatty acids (SCFAs) production during in vitro digestion and colonic fermentation of commercial roasted (light, medium and dark) coffee beans. There was no significant difference found among all three different roasting levels. TPC and DPPH were enhanced 15 mg GAE/g and 60 mg TE/g during gastrointestinal digestion, respectively. For colonic fermentation, the highest TPC and FRAP of all coffee beans was found at 2 and 4 h, respectively. The gastric bioaccessibility of most of the phenolic compounds were relatively higher due to thermal phenolic degradation. Total SCFAs production was only up to 0.02 mM because of thermal polysaccharide decomposition. Light roasted beans exhibited relatively higher phenolic bioaccessibility, antioxidant activities and SCFAs production, which would be more beneficial to gut health.

Bioaccessibility and movement of phenolic compounds from tomato (Solanum lycopersicum) during in vitro gastrointestinal digestion and colonic fermentation

Tomatoes (Solanum lycopersicum) are highly involved in diets consumed worldwide, and are rich in bioactive compounds including phenolics, carotenoids and vitamins. In this study, four different varieties of fresh tomato pulp (Oxheart, Green Zebra, Kumato and Roma) were used to estimate the bioaccessibility of target phenolic compounds during in vitro gastrointestinal digestion and colonic fermentation, and to determine their antioxidant capacity. The production of short chain fatty acids (SCFAs) was also estimated during colonic fermentation. Among these, Roma displayed relatively higher total phenolic content (TPC) and free radical scavenging (2,2'-diphenyl-1-picrylhydrazyl (DPPH) assay) values after gastrointestinal digestion of 0.31 mg gallic acid equivalents (GAE) per g and 0.12 mg Trolox equivalents (TE) per g. Kumato exhibited the highest total flavonoid content (TFC) of 2.47 mg quercetin equivalents (QE) per g after 8 hours of colonic fermentation. Oxheart and Roma showed similar ferric reducing antioxidant power (FRAP) values of around 4.30 mg QE per g after 4 hours of faecal reaction. Catechin was the most bioaccessible phenolic compound in all fresh tomatoes, and could be completely decomposed after intestinal digestion, whereas the release of some bonded phenolic compounds required the action of gut microflora. Kumato and Green Zebra showed higher production of individual and total SCFAs for 16 hours of fermentation, which would provide more gut health benefits.

The Valorization of Spent Coffee Ground Extract as a Prospective Insecticidal Agent against Some Main Key Pests of Phaseolus vulgaris in the Laboratory and Field

The exploitation of massive amounts of food and agro-waste represents a severe social, economic, and environmental issue. Under the growing demand for food products that are free of toxic synthetic insecticides, a methanolic extract of spent coffee grounds (SCGs), which represent the main byproduct of coffee production, was applied in the current study as a bioinsecticide against the main pests of the green bean: Spodoptera littoralis, Agrotis ipsilon, Bemisia tabaci, Empoasca fabae, and Aphis craccivora. A deterrent assay, contact bioassay, and lethal concentration analysis were performed to reveal the repellent, antifeedant, and oviposition deterrent effects. Parallel to the above-mentioned bioassays, the phytochemical composition of the methanolic SCG extract was investigated via a high-performance liquid chromatography (HPLC) analysis. Fourteen phenolic acids and five flavonoids, in addition to caffeine (alkaloid), were identified in the extract. Cinnamic, rosmarinic, and gallic acids were the predominant phenolics, while apigenin-7-glucoside was the main flavonoid, followed by naringin, catechin, and epicatechin. The extract of SCGs showed an insecticidal effect, with a mortality between 27.5 and 76% compared to the control (7.4%) and based on the concentration of the extract used. In the same trend, the oviposition efficiency revealed different batches of laid eggs (0.67, 2.33, 7.33, and 8.67 batches/jar) for 100, 50, and 25% of the SCG extract and the control. Finally, the major components of the SCG extract were docked into the insecticide acetylcholinesterase enzyme to explore their potential for inhibition, where apigenin-7-glucoside showed a higher binding affinity, followed by catechin, compared to the control (lannate). The obtained findings could be a starting point for developing novel bioinsecticides from SCGs.

Functional Compounds from Banana Peel Used to Decrease Oxidative Stress Effects

Banana peel, a little-used waste, contains a high amount of biologically active compounds. The aim of the study is to demonstrate in vitro, the antioxidant, cytotoxic, and antimicrobial effects of hydroalcoholic extracts from yellow (BP) and red (BPR) banana peels. The analysis of the extracts by Capillary Zone Electrophoresis (CZE) has confirmed the presence of several bioactive compounds. BPR has a higher in vitro antioxidant activity than BP, which correlates with a significant cytotoxic, antimicrobial effect, with a UVA/UVB rate of 0.9. In the case of BPR, the results confirm the presence of isoquercitrin and kaempferol in a 1:3 ratio. The bioactive compounds from the extracts have shown a different interaction with HCT-8 cell lines and with tested bacterial strains with pathogenic properties. The HCA analysis proved the biological value of BPR to reduce oxidative stress and its potential use in natural products.

Therapeutic Properties of Edible Mushrooms and Herbal Teas in Gut Microbiota Modulation

Edible mushrooms are functional foods and valuable but less exploited sources of biologically active compounds. Herbal teas are a range of products widely used due to the therapeutic properties that have been demonstrated by traditional medicine and a supplement in conventional therapies. Their interaction with the human microbiota is an aspect that must be researched, the therapeutic properties depending on the interaction with the microbiota and the consequent fermentative activity. Modulation processes result from the activity of, for example, phenolic acids, which are a major component and which have already demonstrated activity in combating oxidative stress. The aim of this mini-review is to highlight the essential aspects of modulating the microbiota using edible mushrooms and herbal teas. Although the phenolic pattern is different for edible mushrooms and herbal teas, certain non-phenolic compounds (polysaccharides and/or caffeine) are important in alleviating chronic diseases. These specific functional compounds have modulatory properties against oxidative stress, demonstrating health-beneficial effects in vitro and/or In vivo. Moreover, recent advances in improving human health via gut microbiota are presented. Plant-derived miRNAs from mushrooms and herbal teas were highlighted as a potential strategy for new therapeutic effects.

In Vitro Coliform Resistance to Bioactive Compounds in Urinary Infection, Assessed in a Lab Catheterization Model

Bioactive compounds and phenolic compounds are viable alternatives to antibiotics in recurrent urinary tract infections. This study aimed to use a natural functional product, based on the bioactive compounds’ composition, to inhibit the uropathogenic strains of Escherichia coli. E.coli ATCC 25922 was used to characterize the IVCM (new in vitro catheterization model). As support for reducing bacterial proliferation, the cytotoxicity against a strain of Candida albicans was also determined (over 75% at 1 mg/mL). The results were correlated with the analysis of the distribution of biologically active compounds (trans-ferulic acid-268.44 ± 0.001 mg/100 g extract and an equal quantity of Trans-p-coumaric acid and rosmarinic acid). A pronounced inhibitory effect against the uropathogenic strain E. coli 317 (4 log copy no./mL after 72 h) was determined. The results showed a targeted response to the product for tested bacterial strains. The importance of research resulted from the easy and fast characterization of the functional product with antimicrobial effect against uropathogenic strains of E. coli. This study demonstrated that the proposed in vitro model was a valuable tool for assessing urinary tract infections with E. coli.

Polyphenol Profiling of Chestnut Pericarp, Integument and Curing Water Extracts to Qualify These Food By-Products as a Source of Antioxidants

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6–7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut’s appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.

Characterization of phytochemical components and identification of main antioxidants in Crateva unilocalaris Buch. shoots by UHPLC-Q-Orbitrap-MS2 analysis

The chemical constituents and antioxidant activity of the three different extracts (80% methanol, 80% ethanol, and 80% acetone) of Crateva unilocalaris Buch. shoots were investigated. Six phenolic compounds and seven saponins were characterized in all extracts. Chikusetsusaponin IVa had the highest content (17.92 to 29.16 mg/g), and chlorogenic acid was the most abundant phenolic compound (10.48 to 13.99 mg/g). The acetone extract had the highest total phenolic, flavonoid, and saponin contents and the strongest antioxidant activity. Moreover, all extracts exhibited good effects on the inhibition of intracellular ROS generation in HepG2 cells. Phenolic compounds but not saponins contributed significantly to the DPPH or ABTS radical scavenging activity of C. unilocalaris shoots according to the results of DPPH•-UHPLC-HRMS and ABTS•+-UHPLC-HRMS analyses. These results may be helpful for further understandings and utilization of C. unilocalaris shoots as a potential natural source in the food or nutraceuticals industry.

Effect of in vitro digestion on bioactive compounds, antioxidant and antimicrobial activities of coffee (Coffea arabica L.) pulp aqueous extract

Effect of in vitro digestion on bioactive compounds, biological activities of coffee pulp extract (CPE) against pathogens and a probiotic (Lactobacillus acidophilus TISTR 1338) was investigated. Total phenolic compound (TPC), chlorogenic acid (CGA), caffeine (CF), total monomeric anthocyanin (TMA), antioxidant and antimicrobial activities of the CPE were determined before and after digestion. After the digestion, the TPC, CGA and CF decreased 7.9, 31.7 and 50.0%, dry weight (dw), respectively. The antioxidant activity decreased 22.6% (DPPH) and 12.4% (FRAP). The CPE inhibited Escherichia coli TISTR 780 and Staphylococcus aureus TISTR 1466 at 150 and 200 mg/mL, respectively. Both CPE and the digested CPE had no effect on the tested probiotics. These results suggest that bioactive compounds of CPE may degrade during in vitro digestion, consequently the antioxidant and antimicrobial properties. Therefore, CPE could be a potential natural antimicrobial for food industry with no effect on the probiotics.

Quantitative Analysis of Solubility Parameters and Surface Properties of Larch Bark Proanthocyanidins

Quantitative characterization of the solubility parameters and surface properties of larch bark proanthocyanidins will lay the foundation for quantitative studies of the interfacial interactions of proanthocyanidin/polymer composites and will improve the compatibility of components, with important practical and scientific significance. Here, the solubility parameters of highly polymerized larch polymeric proanthocyanidins (LPPCs) and less highly polymerized larch oligomeric proanthocyanidins (LOPCs) were determined experimentally by inverse gas chromatography (IGC). These values were then compared with the solubility parameters obtained using molecular dynamics simulations. The experimentally measured solubility parameters of LPPCs and LOPCs (20.5 and 22.09 (J/m⁻³)^0.5, respectively) were in good agreement with the solubility parameters determined by molecular dynamics simulations (20.57 and 22.35 (J/m⁻³)^0.5, respectively. IGC was also used to experimentally determine the total surface energy, which includes the dispersive component of surface energy γsd  and the specific component of surface energy γssp, together with the surface acidity and basicity parameters of LPPCs and LOPCs at different temperatures. The surface properties of proanthocyanidins can be quickly and accurately evaluated by IGC, and both LPPCs and LOPCs were shown to be amphoteric materials. This study provides theoretical and technical support for the use of larch bark proanthocyanidins, which are non-toxic, renewable, and have good ultraviolet resistance, in the field of blending composites. The study also provides a reference for other studies on the interfacial interactions of wood fiber polymer composites.

Probiotic and Antioxidant Potential of Lactobacillus reuteriLR12 and Lactobacillus lactisLL10 Isolated from Pineapple Puree and Quality Analysis of Pineapple-Flavored Goat Milk Yoghurt during Storage

In recent years, studies have focused on the therapeutic properties of probiotics to eliminate pathogenic microorganisms associated with various diseases. Lactobacilli are important probiotics groups that have been found to possess many health-promoting activities. This study was carried out to isolate LactobacillusreuteriLR12 and L. lactisLL10 from pineapple puree. The invitro analysis to evaluate probiotic characteristics of the isolated bacteria included survival in bile and acid tolerance. The cell-free supernatant of L. reuteri LR12 was effective against various pathogenic bacteria and fungi compared with L. lactisLL10. These two bacterial strains have strong anti-biofilm activity (100%) against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus. The bacterial strains exhibited adhesion properties to HT-29 cells (human colorectal adenocarcinoma). These bacteria showed DPPH- (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical scavenging activity, scavenging of hydroxyl radical activity, superoxide radical scavenging activity, and reducing power activity in the range of 72% ± 3%to 89.3% ± 1.7%, 64% ± 2.7%to 66.8% ± 1.5%, 59.8% ± 4.1% to 63.8% ± 2.1%, and 60.4% ± 1.8%to 66.1% ± 3.3%, respectively. Pineapple puree was used as the starter culture with milk for 2 days for yogurt preparation. Pineapple puree increased flavor and showed the physicochemical properties of yogurt. The finding of the sensory evaluation revealed no significant change compared with the control, except the appearance of yogurt. These findings show that Lactobacilli and pineapple puree have potential use in various probiotic preparations for the fermentation industry.