The composition of potentially bioactive triterpenoid glycosides in red raspberry is influenced by tissue, extraction procedure and genotype

Raspberry polyphenols alleviate neurodegenerative diseases: through gut microbiota and ROS signals

Neurodegenerative diseases are neurological disorders that become more prevalent with age, usually caused by damage or loss of neurons or their myelin sheaths, such as Alzheimer's disease and epilepsy. Reactive oxygen species (ROS) are important triggers for neurodegenerative disease development, and mitigation of oxidative stress caused by ROS imbalance in the human body is important for the treatment of these diseases. As a widespread delicious fruit, the raspberry is widely used in the field of food and medicine because of its abundant polyphenols and other bioactive substances. Polyphenols from a wide variety of raspberry sources could alleviate neurodegenerative diseases. This review aims to summarize the current roles of these polyphenols in maintaining neurological stability by regulating the composition and metabolism of the intestinal flora and the gut-brain axis signal transmission. Especially, we discuss the therapeutic effects on neurodegenerative diseases of raspberry polyphenols through intestinal microorganisms and ROS signals, by means of summary and analysis. Finally, methods of improving the digestibility and utilization of raspberry polyphenols are proposed, which will provide a potential way for raspberry polyphenols to guarantee the health of the human nervous system.

Alchemilla viridiflora Rothm.: the potent natural inhibitor of angiotensin I-converting enzyme

Alchemilla viridiflora Rothm., Rosaceae is a herbaceous plant widespread in central Greece, Bulgaria, North Macedonia and Serbia with Kosovo. Liquid chromatography-mass spectrometry analysis leads to the identification of 20 compounds in methanol extract, mainly ellagitannins and flavonoid glycosides. Given that various plant extracts have traditionally been used to treat hypertension and that some of the analyzed methanol extract constituents have beneficial cardiovascular effects, we hypothesized that some of these effects are achieved by inhibiting angiotensin I-converting enzyme (ACE). The dose-dependent ACE inhibitory activities of A. viridiflora and miquelianin were observed with an IC₅₀ of 2.51 ± 0.00 µg/mL of A. viridiflora extract compared to the IC₅₀ of 5.4139 ± 0.00 µM for miquelianin. The contribution of the single compounds to the tested activity was further analyzed through the in silico experimental approach. Computational docking results showed that tiliroside, ellagic acid pentose and galloyl-hexahydroxydiphenoyl-glucose exhibited even better binding affinity for the ACE active site than miquelianin, for which ACE activity was confirmed by an in vitro assay.

Bioaccessible Raspberry Extracts Enriched in Ellagitannins and Ellagic Acid Derivatives Have Anti-Neuroinflammatory Properties

Chronic neuroinflammation associated with neurodegenerative disorders has been reported to be prevented by dietary components. Particularly, dietary (poly)phenols have been identified as having anti-inflammatory and neuroprotective actions, and their ingestion is considered a major preventive factor for such disorders. To assess the relation between (poly)phenol classes and their bioactivity, we used five different raspberry genotypes, which were markedly different in their (poly)phenol profiles within a similar matrix. In addition, gastro-intestinal bio-accessible fractions were produced, which simulate the (poly)phenol metabolites that may be absorbed after digestion, and evaluated for anti-inflammatory potential using LPS-stimulated microglia. Interestingly, the fraction from genotype 2J19 enriched in ellagitannins, their degradation products and ellagic acid, attenuated pro-inflammatory markers and mediators CD40, NO, TNF-α, and intracellular superoxide via NF-κB, MAPK and NFAT pathways. Importantly, it also increased the release of the anti-inflammatory cytokine IL-10. These effects contrasted with fractions richer in anthocyanins, suggesting that ellagitannins and its derivatives are major anti-inflammatory (poly)phenols and promising compounds to alleviate neuroinflammation.

A systematic review of in vitro studies evaluating the inhibitory effects of polyphenol-rich fruit extracts on carbohydrate digestive enzymes activity: a focus on culinary fruits consumed in Europe

Evidence shows that polyphenols can attenuate postprandial blood glucose responses to meals containing digestible carbohydrate. Polyphenol-rich plant extracts are emerging as potential ingredients in functional foods and/or beverages despite limited understanding of their physiological effects. Many studies have investigated the mechanisms of polyphenol-rich fruit extracts on inhibition of digestive enzymes. However, the evidence available has yet to be critically evaluated systematically. This report reviews the in vitro literature to quantify the effect of fruit polyphenol extracts on the activities of digestive carbohydrases. A systematic literature search was conducted using six science databases. Included studies, totaling 34 in number, were in vitro digestion models which quantified gut digestive enzyme(s) activity on starch digestion in the presence of fruit polyphenol extracts. Most studies assessed the effects of fruit extracts on either α-amylase (n = 30) or α-glucosidase (n = 30) activity. Studies were consistent overall in showing stronger inhibition of α-amylase compared to α-glucosidase by proanthocyanidin- and/or ellagitannin-rich fruit extracts. Recommendations are proposed for future reporting of this type of research to enable meaningful synthesis of the literature as a whole. Such knowledge could allow effective choices to be made for development of novel functional foods and beverages.

Sulforaphane-enriched extracts from glucoraphanin-rich broccoli exert antimicrobial activity against gut pathogens in vitro and innovative cooking methods increase in vivo intestinal delivery of sulforaphane

Purpose

Studies on broccoli (Brassica oleracea var. italica) indicate beneficial effects against a range of chronic diseases, commonly attributed to their bioactive phytochemicals. Sulforaphane, the bioactive form of glucoraphanin, is formed by the action of the indigenous enzyme myrosinase. This study explored the role that digestion and cooking practices play in bioactivity and bioavailability, especially the rarely considered dose delivered to the colon.

Methods

The antimicrobial activity of sulforaphane extracts from raw, cooked broccoli and cooked broccoli plus mustard seeds (as a source myrosinase) was assessed. The persistence of broccoli phytochemicals in the upper gastrointestinal tract was analysed in the ileal fluid of 11 ileostomates fed, in a cross-over design, broccoli soup prepared with and without mustard seeds.

Results

The raw broccoli had no antimicrobial activity, except against Bacillus cereus, but cooked broccoli (with and without mustard seeds) showed considerable antimicrobial activity against various tested pathogens. The recovery of sulforaphane in ileal fluids post soup consumption was < 1% but the addition of mustard seeds increased colon-available sulforaphane sixfold. However, when sulforaphane was extracted from the ileal fluid with the highest sulforaphane content and tested against Escherichia coli K12, no inhibitory effects were observed. Analysis of glucosinolates composition in ileal fluids revealed noticeable inter-individual differences, with six “responding” participants showing increases in glucosinolates after broccoli soup consumption.

Conclusions

Sulforaphane-rich broccoli extracts caused potent antimicrobial effects in vitro, and the consumption of sulforaphane-enriched broccoli soup may inhibit bacterial growth in the stomach and upper small intestine, but not in the terminal ileum or the colon.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02322-0) contains supplementary material, which is available to authorized users.

Isolation of enantiomeric furolactones and furofurans from Rubus idaeus L. with neuroprotective activities

A phytochemical study on the fruits of Rubus idaeus L. (Rosaceae) yielded eight pairs of enantiomeric lignans, including one undescribed furolactone named (-)-idaeusinol A and six undescribed furofuran derivatives named (+/-)-idaeusinol B-D. The structures of these isolated compounds were elucidated by spectroscopic analyses and a combination of computational techniques including gauge-independent atomic orbital (GIAO) calculation of 1D NMR data and TD-DFT calculation of electronic circular dichroism (ECD) spectra. Bioactivity screenings suggested that (+)-idaeusinol D exhibited the most significant protective effect against H₂O₂-induced neurotoxicity at the concentration of 25 μM. In contrast, (-)-idaeusinol D, as the enantiomer of (+)-idaeusinol D, showed no effect against H₂O₂-induced neurotoxicity at both 25 and 50 μM concentration.

Genoprotective Effects of Essential Oil Compounds Against Oxidative and Methylated DNA Damage in Human Colon Cancer Cells

Essential oils (EO) are widely used in foods as flavoring and preservative agents. Many of the biological activities of EO have been attributed to major essential oil compounds (EOC) but their direct interaction with colonic epithelial cells and their genotoxic and genoprotective effects are not well established. In this study, the cytotoxicity and genotoxicity of EOC including nerolidol, thymol, geraniol, methylisoeugenol, eugenol, linalool, and a commercial blend (Agolin) were determined. Furthermore, the genoprotective effects of EOC against oxidative and methylating damage were assessed using the comet assay in HT-29 colorectal adenocarcinoma cells. The majority of EOC were cytotoxic to HT-29 cells at or above 250 ppm after 24 hr exposure. At noncytotoxic doses, none of the EOC was genotoxic in the comet assay. Genoprotection against oxidative DNA damage was observed for nerolidol (at 62.5 ppm), thymol (at 12.5 ppm), geraniol, and methylisoeugenol (both at 125 ppm), as well as linalool and Agolin (both at 250 ppm). Thymol was the most protective compound against oxidative DNA damage and geraniol (at 125 ppm) also protected cells against methylating DNA damage. This study highlights the potential of EOC such as thymol to protect the colonic epithelium against oxidative DNA damage and geraniol against methylating DNA damage. Further in vivo studies are needed to confirm these findings for safety and efficacy to exploit their potential pharmaceutical or nutraceutical uses for colonic health.