Polyphenolic profile and antioxidant activities of Madeiran elderberry (Sambucus lanceolata) as affected by simulated in vitro digestion

The fermentation of whey protein and mulberry polyphenols by forming protein-phenolic adducts: Improved digestions

The impacts of forming adduct between whey protein (WP) and mulberry polyphenol (MP) on the digestion and fermentation of WP and MP were investigated using an in vitro model. The results showed that MP increased the in vitro antioxidant capacity of WP digestive products. After forming adduct the total extractable phenolic content of MP dropped from 440.20 mg GAE/g to 21.53 mg GAE/g. The total extractable phenolic content of WP-MP group decreased from 21.53 mg GAE/g to 11.77 mg GAE/g after the oral digestion, then slightly increased to 12.43 after the gastric digestion and continuously increased to 20.43 mg GAE/g after the intestinal digestion. Extractable individual phenolic compounts exhibited the similar tendency, in which cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, p-coumaric acid, quercetin and kaempferol were still detectable while protocatechuic and neochlorogenic acid increased after intestinal digestion of WP-MP adduct. Incorporation of MP inhibited the oral and gastric digestion but enhanced the intestinal digestion of WP, and the degree of hydrolysis of WP increased 9.70% after intestinal digestion compared to the control. The fermentation of non-dialyzable residue of WP-MP by gut flora decreased the pH value from 7.18 to 4.82 and increased the proliferation of beneficial bacteria and the production of short-chain fatty acids. These findings indicated that WP-MP adduct increased the digestion of WP and the bioaccessibility of MP, could improve the intestinal health and could be used as a new healthy food ingredient.

In vitro digestion and fermentation of the whole goji berry: Bioactive ingredients change and impacts on human gut microbiota

Goji berry (Lycium barbarum L.) is a nutrient-rich fruit and has received enormous interest for its health benefits. The beneficial effects of goji berry are linked to the absorption of bioactive compounds within the gastrointestinal digestion process and colon fermentation. Nonetheless, how certain bioactive compounds were released, and metabolism changed of the consumption of whole goji berries were still unclear. Therefore, the present study aimed to evaluate the digestion characteristics of key bioactive compounds in whole goji berries with an in vitro digestion model, and the effects of whole goji berries on the structure of gut microbiota were also investigated. Results showed that a significant release of carbohydrates during the digestion process, peaking within the first 15 min of the intestinal phase (421.4 ± 5.82 mg GE/g, dry weight, respectively), was observed, and the phenolic release reached the highest in the first 15 min of the gastric phase. Meanwhile, the bioaccessibilities of phenolic compounds and carbohydrates were determined to be 63.87% and 80.40%, respectively, after intestinal digestion. In addition, the undigested fractions of goji berries could be further fermented to produce short-chain fatty acids, which decreased the colon pH value (from 7.38 to 6.71) as well as the Firmicutes/Bacteroidetes ratio. Moreover, the goji berries regulated the composition of gut microbiota by promoting beneficial bacteria such as Bacteroides, Parabacteroides, and Paraclostridium, whereas inhibiting the proliferation of harmful bacteria (e.g., Fusobacterium). Our results indicated that the goji berry exhibited significant bioactivity during the digestion and fermentation stage and might provide some new insights into the utilization of goji berries in healthy food processing.

Comparisons in phytochemical components and in vitro digestion properties of corresponding peels, flesh and seeds separated from two blueberry cultivars

Highbush blueberries (HB) and rabbiteye blueberries (RB) were separated into peels, flesh, and seeds to assess the compositions of nutriment, anthocyanins, soluble sugars and fatty acids, and the in vitro digesting abilities. Total phenolics contents (TPC) of 51-56 mg GAE/g DW were found in blueberry peels. Compared with HB peels, RB peels showed much higher TPC, but only contained 35 phenolics and lacked peonidin-3-O-rutinoside. Glucose, fructose, and sucrose were all present in HB and RB, but RB flesh had a higher acid-sugar ratio. Unsaturated fatty acid concentrations in HB and RB seeds were comparable (26.65 and 26.43 mg/g, respectively). However, HB seeds have 35 fatty acids, but RB seeds lacked cis-4,7,10,13,16,19-docosahexaenoic acid and cis-10-pentadecenoic acid. The in vitro digestion test showed that the whole fruit/peels/flesh of RB had a higher recovery and bioavailability index of phenolics and anthocyanins. Therefore, the reuse of blueberry pomace needs to be emphasized.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01326-w.

Effect of In Vitro Gastrointestinal Digestion on Phytochemicals and Antioxidant Activities in Cherry Tomatoes (Solanum lycopersicum var. cerasiforme)

We investigated the impact of simulated in vitro gastrointestinal digestion on the levels of total polyphenols, total flavonoids, carotenoids, and antioxidant capacity in cherry tomatoes. The initial total polyphenol content of fresh tomatoes was 220.51 μg GAE/g, which decreased to 203.24 μg GAE/g after 120 min of stomach treatment and further decreased to 138.23 μg GAE/g after 120 min of small intestine treatment. Similarly, the initial total flavonoid content in fresh tomatoes was 43.28 μg QE/g, but after 120 min of small intestine digestion, it decreased by approximately 50.72% to 21.33 μg QE/g. Lycopene, lutein, and β-carotene also experienced a decrease of 69.71∼78.38% during the digestion process compared to fresh tomatoes. The antioxidant activity exhibited a reduction of 34.95∼37.67% compared to fresh tomatoes after digestion in the stomach and intestines. The bioactive compounds present in tomatoes undergo decomposition and conversion into other substances during digestion, and these degradation products are believed to inhibit the growth of SK-Hep1 human hepatoma cells while enhancing antioxidant activity within the intracellular environment.

Polyphenolic profiles of a variety of wild berries from the Pacific Northwest region of North America

Polyphenols have been extensively profiled and quantified in commercially grown berries, but similar information is sparsely available for wild berries. Because polyphenolic contents are inherently associated with berries health benefits, determining phenolic profiles is an important step for strategizing potential uses by the industry and for health and nutrition outcomes. Here, we profiled phenolic compounds in wild berries commonly encountered and harvested in the Pacific Northwest region of North America. Huckleberries (Vaccinium membranaceum) of varying phenotypes were found to be comparable to related blueberries in terms of general phenolic classes composition. However, all huckleberries exhibited markedly high levels of cyanidins, and delphinidins or peonidins were also higher in specific phenotypes. Wild black elderberries (Sambucus nigra spp. Canadensis) were found to have remarkably high phenolic, especially anthocyanins, in line with reports from cultivated elderberries. Saskatoon serviceberries (Amelanchier alnifolia) were found to exhibit high polyphenol content, but with a less diverse profile dominated by quercetin. The most intriguing berry may be the Oregon grape (Mahonia Aquifolium) being the only one exhibiting more than one g of polyphenols per 100 g; as well as a remarkably even distribution of the different anthocyanin classes. All colored wild berries were found to have at minimum comparable total phenolic contents when compared to cultivated and other wild berries, suggesting they should exhibit comparable human health benefits such as antioxidant and metabolic syndrome preventative potential described for these other berries. Overall, our data represents a valuable resource to explore the potential to valorize wild berry species for their specific phenolic profiles and predicted nutritional and health properties. With repeated phenolic profiling to better understand the impact of the environment, the wild berries described here hold promises both as food ingredient applications as well as valuable complement for healthy dietary patterns.

Enriched Red Wine: Phenolic Profile, Sensory Evaluation and In Vitro Bioaccessibility of Phenolic Compounds

The beneficial health effect of red wine depends on its phenolic content and the phenolic content in red wines is affected by ecological, agricultural, and enological practices. Enriched wines have been proposed as an alternative to increase the phenolic content in wines. Nevertheless, phenolic compounds are related to the sensory characteristics of red wines, so enrichment of red wines requires a balance between phenolic content and sensory characteristics. In the present study, a Merlot red wine was enriched with a phenolic extract obtained from Cabernet Sauvignon grape pomace. Two levels of enrichment were evaluated: 4 and 8 g/L of total phenolic content (gallic acid equivalents, GAE). Wines were evaluated by a trained panel to determine their sensory profile (olfactive, visual, taste, and mouthfeel phases). The bioaccessibility of phenolic compounds from enriched red wines was evaluated using an in vitro digestive model and phenolic compounds were quantified by High Performance Liquid Chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Enrichment increased mainly flavonols and procyanidins. Such an increase impacted astringency and sweetness perceived by judges. This study proposes an alternative to increase the phenolic content in wines without modifying other main sensory characteristics and offers a potential beneficial effect on the health of consumers.

Assessment of the Bioaccessibility of Elaeagnus angustifolia L. Flour and Its Use in Cracker Formulation

In this study, in vitro digestion of polyphenols of oleaster (Elaeagnus angustifolia L.) flour (OF) and the potential use of OF in cracker production were studied. The results showed that 21.90 mg gallic acid equivalent (GAE)/g dry matter (DM) of total polyphenol (TP), 28.15 mg rutin equivalent (RE)/g DM of total flavonoid (TF) and 7709.13 mmol ascorbic acid equivalent (AAE)/100 g DM of antioxidant capacity (AC) were found in OF. The bioaccessibility and content of the OF polyphenols and their AC during in vitro digestion varied depending on the digestion stage. The stability of the OF polyphenols was higher in gastric stage (41.92%) than intestinal one (34.01%). OF was used to replace flour in the cracker formulation at the levels of 5, 10 and 15% (w/w) and increased the TP contents and AC of the crackers compared to the sample without OF (control). The addition of OF to the cracker dough increased the bioaccessibility of the cracker polyphenols. After digestion, bioaccessibilities of enriched crackers (107.90-126.81%) were found higher than that of control sample (93.73%). However, as the level of OF in cracker increased, bioaccessibility of polyphenols decreased. The results generally indicated that oleaster has a good potential for the enrichment of foods.

Characterization of the flavor, sensory quality and in vitro bioaccessibility in cloudy pomegranate juice treated by high pressure and thermal processing

BACKGROUND

Recently, cloudy pomegranate juice (PJ) has become popular due to its rich phenolic and health-promoting effects. The aim of the present work was to evaluate the application of high hydrostatic pressure processing (HPP), pasteurization (PT) and high-temperature short-time sterilization (HTST) on physicochemical properties (color, flow behavior, turbidity, sugars, organic acids, aroma and sensory evaluation) and in vitro bioaccessibility of total phenolics content (TPC), total flavonoids content (TFC) and phenolics of cloudy PJ.

RESULTS

Compared to HPP, thermal sterilization significantly increased the brightness (L*), redness (a*), total color difference (ΔE) and turbidity, and decreased the TPC and TFC. HPP maintained the volatile profile of cloudy PJ better, while thermal sterilization significantly changed the profile by decreasing alcohols 23.8-32.7% and increasing acids by 33.6%-182.8%. The bioaccessibility of flavonoids, phenolic acids and tannins in the control cloudy PJ after in vitro oral-gastric-intestinal digestion were 1.5%, 4.9%, and 9.0%, respectively, which were not significantly changed by different treatments.

CONCLUSION

These results contributed to promoting the color quality and health benefits of cloudy PJ rich in phenolics by optimizing the processing conditions in the food industry. © 2022 Society of Chemical Industry.

Boosting the Bioaccessibility of Dietary Bioactives by Delivery as Protein-Polyphenol Aggregate Particles

Protein-polyphenol aggregate particles concurrently fortify a functional food product with healthy dietary proteins and concentrated polyphenols. However, what impact does ingestion of aggregate particles have on ultimate health relevance of either the polyphenolic molecules in the matrix or the protein molecules? Because human health benefits are contingent on bioavailability after ingestion, the fate of these molecules during transit in the gastrointestinal tract (GIT) will dictate their utility as functional food ingredients. This brief review explores diverse applications of protein-polyphenol particles in the food industry and the bioaccessibility of both bioactive polyphenolic compounds and edible proteins. Evidence to date suggests that complexation of phytoactive polyphenolics effectively enhances their health-relevant impacts, specifically because the phytoactives are protected in the protein matrix during transit in the GIT, allowing intact, non-degraded molecules to reach the colon for catabolism at the gut microbiome level, a prerequisite to realize the health benefits of these active compounds.

Ethnobotany, phytochemistry, pharmacology, and toxicology of the genus Sambucus L. (Viburnaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Sambucus L. (Viburnaceae) consists of about 29 recognized species distributed in all regions of the world except the extremely cold and desert areas. Some species have been used as traditional medicines to treat various disorders such as bone fractures, rheumatism, diabetes, respiratory and pulmonary disorders, skin diseases, inflammatory ailments, diarrhea, and others. However, the currently available data on traditional and pharmacological uses have not been comprehensively reviewed.

STUDY AIM

The present review is designed to provide information on the ethnobotanical uses, phytochemistry, toxicity, and the known biological properties of Sambucus, to understand their connotations and provide a scientific basis and gaps for further research.

MATERIALS AND METHODS

The information was obtained from different bibliographic databases, Google Scholar, Springer Link, Web of Science, PubMed, and Science Direct along with other literature sources such as dissertation before August 2021. The scientific names were validated using The Plant List and World Flora Online websites.

RESULTS

Twelve Sambucus species were found to be frequently mentioned in ethnomedical uses recorded in China, Korea, Turkey, Iran, and other countries. Traditionally, they have been used as remedies to numerous health complications among others, bone fractures and rheumatism, diabetes, wounds, inflammatory diseases, diarrhea, menstrual pains, respiratory and pulmonary complaints, skin disorders, headaches, snakebites, and urinary tract infections. To date, only eleven species have been studied for their chemical compounds and a total of 425 bioactive constituents, including phenolic compounds, terpenoids, fatty acids, cyanogenic glycosides, phytosterols, lectins, organic acids, alkaloid, coumarin, anthraquinone, and others have been reported. The crude extracts and the isolated chemical constituents exhibited diverse outstanding pharmacological activities including antioxidant, antimicrobial, antidiabetic, anti-inflammatory, antidepressant, analgesic, anti-giardial, immunomodulatory, scolicidal, anti-ulcerogenic, antiradical, bone-protective, anti-glycemic, antiosteoporotic, hypolipidemic, anti-glycation, and wound-healing properties.

CONCLUSION

This study summarized and scrutinized the data on traditional uses, pharmacological activities, phytochemicals, and toxicity of Sambucus species, which indicate they have interesting chemical compounds with diverse biological activities. Many traditional uses of some species from this genus have now been confirmed by pharmacological activities, such as antioxidant, antimicrobial, bone-protective, wound healing, anti-inflammatory, and analgesic properties. However, the currently available data has several gaps in understanding the traditional uses of all Sambucus species. Thus, we strongly recommend further investigations into the scientific connotations between traditional medicinal uses and pharmacological activities, mode of action of the isolated bioactive constituents, and toxicity of other Sambucus species to unravel their efficacy and therapeutic potential for safe clinical application. The current extensive study avails valuable information on therapeutic use of Sambucus species and paves way for further investigations of other useful species, as well as drug discovery.

The Effect of In Vitro Gastrointestinal Digestion on the Antioxidants, Antioxidant Activity, and Hypolipidemic Activity of Green Jujube Vinegar

Healthy fruit vinegar has been extensively favored in China in recent years. As a new type of fruit vinegar developed by our laboratory, green jujube vinegar has the characteristics of good taste and rich nutrition. To study the effect of in vitro gastrointestinal digestion on the antioxidant and hypolipidemic activity of green jujube vinegar, so as to provide basic data for research and the development of healthy food antioxidants, including the total phenolic content (TPC), total flavonoid content (TFC), total acid content, and volatile acid content, were measured. The antioxidant activity was measured by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radical scavenging methods and the ferric reducing antioxidant power assay (FRAP), and the hypolipidemic activity was measured by cholesterol adsorption and the sodium cholate adsorption capacities. The results show that gastric digestion significantly (p < 0.05) decreased the TPC, TFC, total acid content, and volatile acid content, for which the highest reductions were up to 54.17%, 72%, 88.83% and 82.35%, respectively. During intestinal digestion, the TFC remained at a high level and unchanged, and the TFC and volatile acid content significantly (p < 0.05) decreased by 72.66% and 89.05%, respectively. The volatile acid content did not significantly (p > 0.05) change within 2 h. The ABTS free radical scavenging ability and the reducing power free radical scavenging rate were correlated with the TPC, TFC, and total acid contents, and the DPPH free radical scavenging ability and cholesterol adsorption capacity were not. These findings suggest that green jujube vinegar can be a potential functional food for people’s use.

A dynamic view on the chemical composition and bioactive properties of mulberry fruit using an in vitro digestion and fermentation model

Mulberry is a kind of fruit rich in nutrients, however, the beneficial effects of mulberry fruits are related not only to the amount consumed, but also to the bioavailability of these nutrients in the organism. Hence, the aim of this study was to evaluate the bioaccessibility of main bioactive compounds from mulberry fruit using an in vitro digestion model, the changes in bioactivities as well as intestinal flora were also investigated. The results showed that the particle size of the mulberry fruit was gradually reduced (from 196.87 to 60.85 μm), as well as the phenolics and carbohydrates were significantly released during the digestion and maximized in the first 15 min in the intestinal phase (1752 ± 2.80 mg GAE per 100 g, DW; 277.402 ± 2.80 mg GE per 100 g, DW, respectively). Meanwhile, the bioaccessibility indices for phenolic compounds and carbohydrates were 55.49% and 84.62%. The antioxidant activity and α-glucosidase inhibitory effect of the mulberry fruit were positively correlated with their total content of released phenolic compounds. And the phenolic compounds (2,4,6-trihydroxybenzoic acid, cyanidin-3-O-glucoside, 3,4-dihydroxybenzoic acid and gallic acid) were the main compounds that inhibit the α-glucosidase activity by binding to its active cavity through hydrogen bonds. In addition, the mulberry fruit undigested fractions could be further fermented by intestinal microorganisms to produce short-chain fatty acids (SCFAs), which decreased the colon pH value (from 5.93 to 4.79) and the Firmicutes/Bacteroidetes ratio which was beneficial for obesity. Our results indicated that the mulberry fruit exhibited good bioactivity during digestion and fermentation, and could be a promising candidate as a dietary source of functional foods.

In vitro digestion of the whole blackberry fruit: bioaccessibility, bioactive variation of active ingredients and impacts on human gut microbiota

In vitro digestion and fermentation of blackberry fruit was investigated, and results showed that the phenolics were mainly released in gastric phase while carbohydrates in small intestinal phase. The bioaccessibility for phenolics and carbohydrates were 42.80% and 69.30%, indicating most of phenolics still remain in colon and available for intestinal flora. The total phenolics released during the digestion account for the improvement of antioxidant and hypoglycemic activities. Especially, cyanidin-3-O-glucoside with higher released amount and bioaccessibility index (63.21%), exhibited the strongest α-glucosidase inhibitory activity. After fermentation, the non-digestible fractions of blackberry affected the ecosystem of the intestinal tract by decreasing the colonic pH (△pH = 1.10), enhancing the production of SCFAs and modulating gut microbiota composition (the ratio of Firmicute/Bacteroidetes decreased from13.18 to 0.87). The results provided insights into the digestive properties and health benefits of blackberry fruit after consumption.

Application of X-ray diffraction and energy dispersive spectroscopy in the isolation of sulfated polysaccharide from Porphyra haitanensis and its antioxidant capacity under in vitro digestion

BACKGROUND

The separation and purification of Porphyra haitanensis polysaccharide (PHP), and the determination of changes in molecular weight (Mw) and antioxidant capacity after in vitro digestion, were undertaken.

RESULTS

Analysis of two polysaccharide fractions (PHP0.5-1-UF and PHP1.0-1-UF) by various techniques showed that they were very pure sulfated polysaccharides without pigment or protein. PHP0.5-1-UF was filamentous or 'tape-like' sheets, whereas PHP1.0-1-UF had some filaments and large numbers of rounded aggregates. The Mw of PHP, PHP0.5-1-UF and PHP1.0-1-UF was 2.06 × 10⁶ (±2.02%), 6.68 × 10⁶ (±3.17%), and 1.14 × 10⁶ (±3.44%) (g mol^-1 ), respectively. After in vitro digestion, the Mw of PHP, PHP0.5-1-UF, and PHP1.0-1-UF decreased. Their antioxidant capacities were markedly higher than before digestion, especially PHP0.5-1-UF and its digestion products, which might be related to the reductions in Mw.

CONCLUSION

These findings provide a greater understanding of the separation and purification of sulfated polysaccharides and the influence of digestion on biological activity. They also contribute to the practical application of sulfated polysaccharides in functional foods. © 2021 Society of Chemical Industry.

Hydrothermal Processing and In Vitro Simulated Human Digestion Affects the Bioaccessibility and Bioactivity of Phenolic Compounds in African Pumpkin (Momordica balsamina) Leaves

The African pumpkin (Momordica balsamina) contains bioactive phenolic compounds that may assist in reducing oxidative stress in the human body. The leaves are mainly consumed after boiling in water for a specific time; this hydrothermal process and conditions of the gastrointestinal tract may affect the presence and bioactivity of phenolics either positively or negatively. In this study, the effects of hydrothermal processing (boiling) and in vitro simulated human digestion on the phenolic composition, bioaccessibility and bioactivity in African pumpkin were investigated in comparison with those of spinach (Spinacia oleracea). A high-resolution ultra-performance liquid chromatography, coupled with diode array detection, quadrupole time-of-flight and mass spectrometer (UPLC-DAD-QTOF-MS) was used to profile phenolic metabolites. Metabolites such as 3-caffeoylquinic acid, 5-caffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid were highly concentrated in the boiled vegetable extracts compared to the raw undigested and all digested samples. The majority of African pumpkin and spinach extracts (non-digested and digested) protected Deoxyribonucleic acid (DNA), (mouse fibroblast) L929 and human epithelial colorectal adenocarcinoma (Caco-2) cells from 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidative damage. From these results, the consumption of boiled African pumpkin leaves, as well as spinach, could be encouraged, as bioactive metabolites present may reduce oxidative stress in the body.

Using polyphenols as a relevant therapy to diabetes and its complications, a review

Diabetes is currently a worldwide health concern. Hyperglycemia, hypertension, obesity, and oxidative stress are the major risk factors that inevitably lead to all the complications from diabetes. These complications severely impact the quality of life of patients, and they can be managed, reduced, or even reverted by several polyphenols, plant extracts and foods rich in these compounds. The goal of this review is to approach diabetes not as a single condition but rather an interconnected combination of risk factors and complications. This work shows that polyphenols have multi target action and effects and they have been systematically proven to be relevant in the reduction of each risk factor and improvement of associated complication.

Assessment of Bioactive Compounds under Simulated Gastrointestinal Digestion of Bee Pollen and Bee Bread: Bioaccessibility and Antioxidant Activity

Bee pollen and bee bread have always been regarded as excellent natural resources for application in food and pharmaceutical fields due to their rich nutrient content and diversity of bioactive compounds with health-improving properties. Extensive studies on both bee products as ingredients for a healthy diet were reported, although the data concerning their metabolization on the gastrointestinal tract is quite limited. Here, we report, at each digestive stage, the bioactive profile for both bee products, their bioaccessibility levels and the antioxidant activity evaluation. The findings indicated that the average bioaccessibility level of total phenolic and total flavonoid content for bee pollen was 31% and 25%, respectively, while it was 38% and 35% for bee bread. This was reflected in a decrease of their antioxidant capacity at the end of in vitro gastrointestinal digestion, both in free radicals scavenging capacity and in reducing power. Moreover, within the 35 phytochemicals identified, the most affected by gastrointestinal digestion were phenylamides, with a complete digestibility at the end of the intestinal phase. Overall, our results highlight that bioactive compounds in both raw products do not reflect the real amount absorbed in the intestine, being bee bread more accessible in bioactive content than bee pollen.

Interactions between Blackcurrant Polyphenols and Food Macronutrients in Model Systems: In Vitro Digestion Studies

Blackcurrant pomace, rich in fiber and polyphenols, can be used as added-value ingredient for food formulation. However, the bounding of polyphenols to pomace and the interactions that take place with food nutrients modify polyphenol bioaccessibility. This work studied the interactions between polyphenols and the main macronutrients in foods, and the changes that occurred during in vitro digestion, using model systems. Model systems were formulated with (i) water, (ii) wheat starch, (iii) olive oil, (iv) whey protein, and (v) a model combining all the ingredients. Polyphenols were added from two sources: as pomace and as a polyphenolic pomace extract. Interactions between polyphenols and macronutrients were studied using light microscopy; total phenolic content (TPC) and antioxidant capacity (AC) were determined before and after the in vitro digestion process. Lastly, the bioaccessibility of the samples was calculated. Polyphenols incorporated into the model systems as pomace increased their bioaccessibility if compared to polyphenols added as extract. For single-nutrient model systems formulated with pomace, the bioaccessibility was higher than when the system contained all the nutrients. Of all the components studied, the greatest effect on bioaccessibility was observed for proteins.

Changes in bioactive compounds and antioxidant activity of plant-based foods by gastrointestinal digestion: a review

Phenolic compounds, omnipresent in plants, are a crucial part of the human diet and are of considerable interest due to their antioxidant properties and other potential beneficial health effects, for instance, antidiabetic, antihypertensive, anti-inflammatory, and anticancer properties. The consumption of a variety of plant-based foods containing various phenolic compounds has increased due to published scientific verification of several health benefits. The release of phenolic compounds and change in their bioactivities examined through in vitro simulated gastrointestinal digestion could provide information on the biological potency of bioactive components, which will allow us to elucidate their metabolic pathways and bioactivities at target sites. This review reports on the recent research results focused on changes during the gastro and/or intestinal phase. The effect of digestive enzymes and digestive pH conditions during simulated digestion accounted for the variations in bioaccessibility and bioavailability of phenolic antioxidants as well as the corresponding antioxidant activities were also summarized and presented in the review.

In vitro simulated digestion and colonic fermentation of lychee pulp phenolics and their impact on metabolic pathways based on fecal metabolomics of mice

Biochemical change and bioactivities of lychee pulp phenolics following simulated human digestion and in vivo metabolism in mice.

Integral use of Isabel grapes to elaborate new products with nutritional value and functional potential

Abstract The benefits of grape consumption are widely recognized and mostly due to phenolic compounds. These beneficial effects will depend on the bioaccessibility of these compounds on grape and its derivatives. This study elaborated two formulations of Isabel grape preparation: PAX (with agave and xylitol) and PS (with sucrose); and two formulations of Isabel grape flour: FAX (from the PAX process residues) and the FS (from the PS process residues). The products were analyzed regarding their nutritional and antioxidant properties; their phenolic compounds’ bioaccessibility was also verified through a simulated digestion model. The preparation and flour exhibited relevant sugars levels (10.83-49.71 g 100 g-1). Those produced with natural sweeteners had a reduction in sugar concentration of 51% and 29% for preparation and flour, respectively, compared to formulations with sucrose, with the high fiber content in the flour is being further highlighted (20.14-21.95 g 100 g-1). The catechin (2.37-28.11 mg 100 g-1) was the most bioaccessible compound (22% to 168%), which together with the caftaric acid (2.31-69.43 mg 100 g-1) and malvidin 3-glucoside (8.65-16.47 mg 100 g-1) represent the compounds observed in greater quantity. The preparations showed higher bioaccessibility regarding grapes and flours for most of the phenolic compounds. Furthermore, the products elaborated presented higher values of anthocyanins and antioxidant activity than the in natura grape, highlighting the beneficial effect of grape processing.

Capsular Polysaccharide From Bacteroides fragilis Protects Against Ulcerative Colitis in an Undegraded Form

The prominent human symbiont Bacteroides fragilis protects animals from intestinal diseases, such as ulcerative colitis, and its capsular polysaccharide plays a key role in reducing inflammation. B. fragilis strain ZY-312 was isolated from the feces of a healthy breast-fed infant, and the zwitterionic capsular polysaccharide zwitterionic polysaccharide, TP2, was extracted. In rats with 2,4-dinitrobenzenesulfonic acid (DNBS)-induced enteritis, TP2 at an optimal dose of 2.5 mg/kg could significantly alleviate enteritis and reduced the degree of intestinal adhesions, the intestinal ulcer area, and the incidence of ulcers in rats. To understand the underlying mechanism, TP2 was labeled with Fluorescein isothiocyanate and orally administered at a dose of 2.5 mg/kg in rats. TP2 was mainly distributed in the cecum and colorectum, but it was not detected in the blood and other organs except that a compound with a molecular weight greater than that of TP2-FITC was found in liver tissue. During the absorption, distribution, metabolism, and excretion, TP2 was indigestible. These results were further confirmed by investigation in the simulated gastric, intestinal fluid, and colonic fluid with fecal microbiota in vitro, where TP2 remained unaltered at different time points. Furthermore, flora composition was analyzed in simulated colonic fluid with TP2 added and it was found that TP2 increased the abundance of Faecalibacterium, Enterococcus romboutsia, and Ruminococcaceae, whereas the abundance of the phylum Proteobacteria represented by Sutterella, Desulfovibrio, and Enterobacteriaceae was decreased. However, the amount of short-chain fatty acids in the simulated colonic fluid was not changed by intestinal flora post-TP2 addition. In conclusion, these findings confirmed that TP2, a capsular polysaccharide of B. fragilis, protects against ulcerative colitis in an undegraded form.

Effect of Ultrasound on In Vitro Bioaccessibility of Phenolic Compounds and Antioxidant Capacity of Blackberry (Rubus fruticosus) Residues cv. Tupy

Agro-industries residues of fruit are a source of antioxidant compounds with a possible health impact. The aim of this study was to evaluate the total phenolic content (TPC), total monomeric anthocyanins (TMA), individual phenolic compounds (IPC), antioxidant capacity and in vitro intestinal bioaccessibility from blackberry residues (BR), and ultrasonicated blackberry residues (US-BR). The results showed that BR had higher TPC (4,016.43 mg GAE/100 g DM), TMA (364.53 mg Cy-3-Gl/100 g) antioxidant capacity by ABTS (5,422.38 mg AAE/100 g DM) and FRAP (12511.44 μmol Fe(II)/100 g DM) than US-BR. TPC and TMA obtained by US-BR were more bioaccessible (70 and 51%, respectively) compared to BR (37 and 34%, respectively). The use of ultrasound can aid the extraction of total phenolic compounds and improve their bioaccessibility. After acid hydrolysis, a high amount of individual phenolic compounds (IPC) in US-BR (chlorogenic acid, caffeic acid, apigenin, luteolin and kaempferol) was obtained compared with BR. Before in vitro digestion, total individual compounds (TIC) content was lower in the BR (29.49 mg/100 g DM) than US-BR (92.36 mg/100 g DM) and there was 5 and < 1%, respectively. Therefore, the food industry would use residues of blackberry fruits as a source of antioxidant compounds with possible health benefits.

Oxidative Stress, Antioxidant Capabilities, and Bioavailability: Ellagic Acid or Urolithins?

Oxidative stress (OS), triggered by overproduction of reactive oxygen and nitrogen species, is the main mechanism responsible for several human diseases. The available one-target drugs often face such illnesses, by softening symptoms without eradicating the cause. Differently, natural polyphenols from fruits and vegetables possess multi-target abilities for counteracting OS, thus representing promising therapeutic alternatives and adjuvants. Although in several in vitro experiments, ellagitannins (ETs), ellagic acid (EA), and its metabolites urolithins (UROs) have shown similar great potential for the treatment of OS-mediated human diseases, only UROs have demonstrated in vivo the ability to reach tissues to a greater extent, thus appearing as the main molecules responsible for beneficial activities. Unfortunately, UROs production depends on individual metabotypes, and the consequent extreme variability limits their potentiality as novel therapeutics, as well as dietary assumption of EA, EA-enriched functional foods, and food supplements. This review focuses on the pathophysiology of OS; on EA and UROs chemical features and on the mechanisms of their antioxidant activity. A discussion on the clinical applicability of the debated UROs in place of EA and on the effectiveness of EA-enriched products is also included.

Enhanced stability of berry pomace polyphenols delivered in protein-polyphenol aggregate particles to an in vitro gastrointestinal digestion model

Stability of protein-polyphenol aggregate particles, created by complexing polyphenols from blueberry and muscadine grape pomaces with a rice-pea protein isolate blend, was evaluated in an in vitro gastrointestinal model. Recovery index (RI; % total phenolics present post-digestion) was 69% and 62% from blueberry and muscadine grape protein-polyphenol particles, compared to 23% and 31% for the respective pomace extracts. Anthocyanins RI was 52% and 42% from particles (6% and 13% from pomace extracts), and proanthocyanidins RI was 77% and 73% from particles (25% and 14% from pomace extracts), from blueberry and grape, respectively. Protein-polyphenol particle digests retained 1.5 to 2-fold higher antioxidant capacity and suppressed the expression of pro-inflammatory cytokines, iNOS, IL6, and IL1β, compared to unmodified extract digests, which only suppressed IL6. Protein-polyphenol particles as a delivery vehicle in foods may confer better stability during gastrointestinal transit, allow protected polyphenols to reach the gut microbiota, and preserve polyphenol bioactivity.

A New Italian Purple Corn Variety (Moradyn) Byproduct Extract: Antiglycative and Hypoglycemic In Vitro Activities and Preliminary Bioaccessibility Studies

The reuse of byproducts from agricultural and food industries represents the key factor in a circular economy, whose interest has grown in the last two decades. Thus, the extraction of bioactives from agro-industrial byproducts is a potential source of valuable molecules. The aim of this work was to investigate the in vitro capacity of byproducts from a new Italian corn variety, named Moradyn, to inhibit the accumulation of advanced glycation end products (AGEs) involved in several chronic age-related disorders. In addition, the hypoglycemic effect of Moradyn was tested by in vitro enzymatic systems. A Moradyn phytocomplex and its purified anthocyanin fraction were able to inhibit fructosamine formation and exhibited antiglycative properties when tested using BSA-sugars and BSA-methylglyoxal assays. These properties could be attributed to the polyphenols, mainly anthocyanins and flavonols, detected by RP-HPLC-DAD-ESI-MSⁿ. Finally, a Moradyn phytocomplex was submitted to a simulated in vitro digestion process to study its bioaccessibility. Moradyn could be considered as a promising food ingredient in the context of typical type 2 diabetes risk factors and the study will continue in the optimization of the ideal formulation to preserve its bioactivities from digestion.

Structural changes in mulberry (Morus Microphylla. Buckl) and chokeberry (Aronia melanocarpa) anthocyanins during simulated in vitro human digestion

Mulberry and chokeberry are rich sources of anthocyanins. In this study, the effect of the anthocyanin composition on the anthocyanin profile changes during in vitro digestion (mimicking the physiological conditions) was investigated by UHPLC-(ESI)-qTOF and UHPLC-(ESI)-QqQ. The antioxidant activity before and after in vitro digestion was elucidated. Cyanidin-3-O-glucoside and cyanidin-3-O-galactoside were dominant in mulberry and chokeberry, respectively. Moreover, the loss of cyanidin-3-O-galactoside in the chokeberry extract after digestion was greater than that of cyanidin-3-O-glucoside in the mulberry extract. After digestion, phenolic acids including protocatechuic acid and various cyanidin conjugates were newly formed because of decomposition and changes in the cyanidin-glycosides. The phenolic acid and cyanidin conjugate levels varied depending on the cyanidin glycoside sources in the colonic fraction. Finally, antioxidant activity before and after digestion was higher in the chokeberry extract than in the mulberry extract. Moreover, this activity continuously decreased until intestinal digestion but increased in the colonic fraction.

In Vitro Antidiabetic, Anti-Obesity and Antioxidant Analysis of Ocimum basilicum Aerial Biomass and in Silico Molecular Docking Simulations with Alpha-Amylase and Lipase Enzymes

The present study explored phytochemicals, porcine pancreatic α-amylase (PPA) and lipase (PPL) inhibitory activities and antioxidant potential of polar and nonpolar extracts of the leaves and flowers of Ocimum basilicum and the in-silico mode of interaction between these enzymes and the major chemical constituents of the herb. The hexane extract (HE) and hydro-ethanolic extract (EE) obtained sequentially were used to estimate PPA and PPL inhibitory and antioxidant activities, total phenolic content (TPC) and total flavonoid content (TFC). Chemical constituents of the essential oils and HE were determined by GC-MS (Gas Chromatography-Mass Spectrometry). For PPA inhibition, IC₅₀ (µg/mL) of the extracts were 0.27-0.37, which were close to 0.24 of acarbose, while for PPL inhibition, IC₅₀ (µg/mL) of the extracts were 278.40-399.65, and that of Orlistat 145.72. The flowers EE was most potent antioxidant followed by leaves EE. The leaves EE had highest TPC and TFC followed of flowers EE. The essential oil of flowers had higher estragole (55%) than linalool (37%), while the essential oil of the leaves had higher linalool (42%) than estragole (38%). The HE of the flowers contained higher estragole (42%) than linalool (23%), while of the HE of the leaves too had higher estragole (65%) than linalool (18%). The in-silico molecular docking study showed linalool and estragole to have considerable PPA and PPL binding potential, which were further investigated through molecular dynamics simulations and binding free energy calculations. The PPA and PPL inhibitory activities of O. basilicum extracts and their notable antioxidant potential propose the herb as a multi-target complimentary medicine for diabetes, obesity and oxidative stress.

Release of health-related compounds during in vitro gastro-intestinal digestion of okara and okara fermented with Lactobacillus plantarum

Okara is a highly perishable by-product remaining after filtration of the smashed soybeans seeds in the production of soymilk. Due to its nutritional value, different approaches have been developed to use it as functional ingredient. Fermentation of okara appears as an interesting strategy to preclude spoilage, providing a more stable matrix to be incorporated in the formulation of functional foods. Okara has antioxidant compounds but the effect of fermentation, and their bioaccessibility still need to be investigated. To achieve this aim, the phenolic compounds (as determined by TPC and TFC assays) and the antioxidant properties (as determined by ABTS ^·+, DPPH ^· , O₂ ^·- assays) of okara and okara fermented with Lactobacillus plantarum CIDCA 83114 were assessed both before and after exposure to simulated gastro-intestinal conditions. Before digestion, okara showed higher values of TPC and TFC than the fermented counterpart. Although a decrease of TPC and TFC was observed after exposing okara to gastric conditions, no significant differences between okara and fermented okara were detected. No further decrease of TPC were observed in intestinal conditions. Okara showed higher antioxidant activity than fermented okara. There was a considerable decrease in the antioxidant activity for both samples when exposed to gastric and intestinal conditions. A good correlation between TFC and antioxidant activities was detected, suggesting that flavonoids play an important role as antioxidants. As a whole, this work provides a solid support for the stability of phytochemicals along the digestive process of both okara and fermented okara.

Antiviral activity of Sambucus FormosanaNakai ethanol extract and related phenolic acid constituents against human coronavirus NL63

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Sambucus FormosanaNakai extract reduced cytopathicity and virus yield in HCoV-NL63-infected cells.

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Among phenolic acid constituents, caffeic acid, chlorogenic acid and gallic acid sustained the anti-HCoV-NL63 activity.

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Sambucus FormosanaNakai extract and caffeic acid concentration-dependently inhibited HCoV-NL63 attachment onto cells.

Human coronavirus NL63 (HCoV-NL63), one of the main circulating HCoVs worldwide, causes respiratory tract illnesses like runny nose, cough, bronchiolitis and pneumonia. Recently, a severe respiratory illness outbreak of HCoV-NL63 has been reported in a long-term care facility. Sambucus FormosanaNakai, a species of elderberry, is a traditional medicinal herb with anti-inflammatory and antiviral potential. The study investigated the antiviral activity of Sambucus FormosanaNakai stem ethanol extract and some phenolic acid constituents against HCoV-NL63. The extract was less cytotoxic and concentration-dependently increased anti-HCoV-NL63 activities, including cytopathicity, sub-G1 fraction, virus yield (IC50 = 1.17 μg/ml), plaque formation (IC50 = 4.67 μg/ml) and virus attachment (IC50 = 15.75 μg/ml). Among the phenolic acid constituents in Sambucus FormosanaNakai extract, caffeic acid, chlorogenic acid and gallic acid sustained the anti-HCoV-NL63 activity that was ranked in the following order of virus yield reduction: caffeic acid (IC₅₀ = 3.54 μM) > chlorogenic acid (IC₅₀ = 43.45 μM) > coumaric acid (IC₅₀ = 71.48 μM). Caffeic acid significantly inhibited the replication of HCoV-NL63 in a cell-type independent manner, and specifically blocked virus attachment (IC₅₀ = 8.1 μM). Therefore, the results revealed that Sambucus Formosana Nakai stem ethanol extract displayed the strong anti-HCoV-NL63 potential; caffeic acid could be the vital component with anti-HCoV-NL63 activity. The finding could be helpful for developing antivirals against HCoV-NL63.

Essential Oils as a Feed Additives: Pharmacokinetics and Potential Toxicity in Monogastric Animals

Essential oils (EOs) are now a hot topic in finding modern substitutes for antibiotics. Many studies have shown positive results and confirmed their high antibacterial activity both in vitro and in vivo. Deservedly, there is an attempt to use EOs as a substitute for antibiotics, which are currently limited by legislation in animal breeding. Given the potential of EOs, studies on their fate in the body need to be summarized. The content of EO's active substances varies depending on growing conditions and consequently on processing and storage. Their content also changes dynamically during the passage through the gastrointestinal tract and their effective concentration can be noticeably diluted at their place of action (small intestine and colon). Based on the solubility of the individual EO's active substances, they are eliminated from the body at different rates. Despite a strong antimicrobial effect, some oils can be toxic to the body and cause damage to the liver, kidneys, or gastrointestinal tissues. Reproductive toxicity has been reported for Origanum vulgare and Mentha arvensis. Several publications also address the effect on the genome. It has been observed that EOs can show both genoprotective effects (Syzygium aromaticum) and genotoxicity, as is the case of Cinnamomum camphor. This review shows that although oils are mainly studied as promising antimicrobials, it is also important to assess animal safety.

Changes in the phenolic compositions of Elaeagnus umbellata and Sambucus lanceolata after in vitro gastrointestinal digestion and evaluation of their potential anti-diabetic properties

In this work, the phenolic composition of E. umbellata leaves and berries is reported. Berries were rich in flavonols, whereas leaves presented abundant flavonols and ellagitannins. Then, the enzyme-inhibitory properties, anti-glycation and antioxidant activities of E. umbellata and Sambucus lanceolata (its phenolic profile has been already established in a previous work) were tested by several in vitro assays and compared. The simulated gastrointestinal digestion resulted in a decrease on their phenolic composition. Nevertheless, both species still had the ability to inhibit aldose reductase activity and protein glycation and scavenge free radicals at the end of the process. Thus, the potential beneficial effects of E. umbellata and S. lanceolata seems to be kept to some extent after passage throughout the digestive system. Altogether, this study provides further insight into investigation of these species as dietary sources of bioactive compounds to lower the risk of type-2 diabetes and obesity.

Phenolic profile and antioxidant activity of Jasonia glutinosa herbal tea. Influence of simulated gastrointestinal in vitro digestion

In order to value J. glutinosa DC (rock tea), we characterised its phenolic profile and antioxidant activity. The study was performed in aqueous extracts before and after a simulated in vitro digestion to obtain data regarding phenolics bioavailability. Methanolic extracts were also analysed for comparison purposes. Phytochemical profiles were determined by high-performance liquid chromatography with mass spectrometric detection, whereas total phenolic content (TPC) and antioxidant assays were performed by conventional spectrophotometric methods. The most abundant compounds were dicaffeoylquinic acids, representing more than 90% of phenolics in tea infusions. Statistically significant differences were observed for all parameters except for TPC in methanol and aqueous extracts. Both phenolics amount and antioxidant activities were lower after the in vitro digestion of the infusions. However, although phenolics were lost during the simulated digestion, rock tea is still a good source of bioactive compounds with potential applications in the pharmaceutical or nutraceutical industries.

Inhibitory Effects of Roseoside and Icariside E4 Isolated from a Natural Product Mixture (No-ap) on the Expression of Angiotensin II Receptor 1 and Oxidative Stress in Angiotensin II-Stimulated H9C2 Cells

Hypertension is a major risk factor for the development of cardiovascular diseases. This study aimed to elucidate whether the natural product mixture No-ap (NA) containing Pine densiflora, Annona muricate, and Monordica charantia, or its single components have inhibitory effects on hypertension-related molecules in Angiotensin II (Ang II)-stimulated H9C2 cells. Individual functional components were isolated and purified from NA using various columns and solvents, and then their structures were analyzed using ESI–MS, ¹H-NMR, and ¹³H-NMR spectra. H9C2 cells were stimulated with 300 nM Ang II for 7 h. NA, telmisartan, ginsenoside, roseoside (Roseo), icariside E4 (IE4), or a combination of two components (Roseo and IE4) were administered to the cells 1 h before Ang II stimulation. The expression and activity of hypertension-related molecules or oxidative molecules were determined using RT-PCR, western blot, and ELISA. Ang II stimulation increased the expression of Ang II receptor 1 (AT1), tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), tumor growth factor-β (TGF-β) mRNA, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and the levels of hydrogen peroxide (H₂O₂) and superoxide anion (•O₂⁻) and reduced anti-oxidant enzyme activity. NA significantly improved the expression or activities of all hypertension-related molecules altered in Ang II-stimulated cells. Roseo or IE4 pretreatment either decreased or increased the expression or activities of all hypertension-related molecules similar to NA, but to a lesser extent. The pretreatment with a combination of Roseo and IE4 (1:1) either decreased or increased the expression of all hypertension-related molecules, compared to each single component, revealing a synergistic action of the two compounds. Thus, the combination of single components could exert promising anti-hypertensive effects similar to NA, which should be examined in future animal and clinical studies.

Polyphenolic Profile and Antioxidant Activity of Leaf Purified Hydroalcoholic Extracts from Seven Mexican Persea americana Cultivars

Persea americana (avocado) is a fruit consumed worldwide; however, since avocado leaves are apparently a natural ingredient that can be used as a traditional medicine, they can be a potential source of bioactive compounds. This study aimed to analyze the antioxidant activity of seven Mexican avocado leaf extracts by DPPH^•, ABTS^•+, and lipid peroxidation (LPO), and to identify the compound profile by liquid chromatography coupled to mass spectrometry/electron spray ionization. The highest free radical-scavenging activity was observed for Platano Delgado and Criollo 6 avocado cultivars havin IC₅₀ values of 271.86 ± 13.69 and 269.56 ± 6.53 for DPPH^• and ABTS^•+ radicals, respectively, while the best result for lipid oxidation inhibition was registered in Criollo 6 cultivar extract. In this study forty-one compounds were detected in avocado leaves of the the seven cultivars analyzed, and of these compounds, eighteen phenolics were identified for first time in such plant material. The present study demonstrated that Mexican cultivars of Persea americana possess diverse polyphenolic compounds with strong antioxidant activity, which might be useful in the food and pharmaceutical industries.

The Prebiotic Activity of Simulated Gastric and Intestinal Digesta of Polysaccharides from the Hericium erinaceus

Hericium erinaceus (HE) is a well-known edible and medicinal fungus widely grown in Asian countries. Polysaccharides from the Hericium erinaceus (HEP) are major biological macromolecules. It has been reported that HEP has multiple biological activities, such as antioxidant activity, immunomodulatory effects, anti-inflammatory effect, anti-chronic gastritis activity, and so on. In the current study, we investigated the biological property of HEP during gastrointestinal digestion. The results indicated that both simulated gastric and small intestinal digesta of HEP has better stimulation of probiotics growth than HEP alone, especially for Lactobacillus plantarum BG112. The prebiotic activity was the strongest when HEP was treated by simulated gastric juice for 2 h and by simulated small intestinal juice for 4 h. The molecular weight (M_w) of HEP decreased from 1.68 × 10⁶ Da and 2.32 × 10⁴ Da to 529.3 ± 7.2 Da, as digestion time increased. Meanwhile, the reducing sugar content was significantly increased from 0.610 ± 0.007 to 22.698 ± 0.752 mg/ml, suggesting that the decrease of M_w was likely due to the breakdown of glycosidic bonds. Considerable mannose and galactopyranose were released throughout the gastrointestinal digestion period, indicating that the gastrointestinal digestion resulted in production of free monosaccharides. After fermentation of L. plantarum BG112, the M_w of HEP was decreased and short chain fatty acids (SCFAs) including acetic acid, isovaleric acid, lactic acid, and butyric acid were produced. We speculated that the release of free monosaccharides during gastrointestinal digestion and utilization of HEP, by the probiotics, contributed to the prebiotic activity of HEP's gastric and intestinal digesta. These results unveiled some mechanisms on the close relationship between the structure and bioactivity of polysaccharides, during digestion.

Evaluation of Rubus grandifolius L. (wild blackberries) activities targeting management of type-2 diabetes and obesity using in vitro models

Rubus grandifolius Lowe (wild blackberries) is an endemic species from Madeira Archipelago (Portugal) used in folk medicine for alleviating diabetic complications. In this work, R. grandifolius methanolic extracts were analysed for in vitro inhibitory effect on digestive enzymes linked to type-2 diabetes, as well as aldose reductase activity and protein glycation. The phenolic composition, antioxidant and cytotoxic activities were also determined. Methanolic extracts exhibited strong inhibition of glucosidases (α- and β), but were less potent for α-amylase and pancreatic lipase when compared to current pharmaceutical drugs. The total phenolic content determined by HPLC-DAD varied between 92.96 - 97.47 and 118.01-137.41 mg g^-1 of dry extract for berries and leaves, respectively. Fifty polyphenols were quantified, anthocyanins and ellagitannins being the main compounds. Cyanidin-3-glucoside was identified as one of the main hypoglycaemic and hypolipidemic agents in all extracts. R. grandifolius also prevented glycation of bovine-serum albumin (BSA) and showed strong radical scavenging activity against tested free radicals. At low concentration, the extracts were not cytotoxic against Caco-2 cells. Based on the results of this study, wild blackberry extracts demonstrated a potential beneficial effect on the control/management of type-2 diabetes mellitus, validating their use in folk medicine.