Raspberry Polyphenols Research Articles

The preventive and inhibitory effects of red raspberries on cancer

Red raspberries are gaining attention more and more for their nutritional and bioactive components, with potential health effects such as antitumor properties. This review aims to describe the antioxidant activities of red raspberries, emphasizing the role of anthocyanins and ellagitannins as primary contributors among red raspberry polyphenols; it also outlined the connection between red raspberries and their role in inhibiting cancer cell growth by regulating oxidative stress. Numerous studies suggest that red raspberries are able to block cancer cell progression by inhibiting proliferation, migration, and autophagy, as well as regulating the cell cycle, angiogenesis, and DNA damage repair. This review sheds light to the growing evidence supporting antioxidants as a crucial link between fruit consumption and cancer prevention.

Raspberry polyphenols target molecular pathways of heart failure

Approximately 650,000 new cases of heart failure (HF) are diagnosed annually with a 50% five-year mortality rate. HF is characterized by reduced left ventricular (LV) ejection fraction and hypertrophy of the LV wall. The pathophysiological remodeling of the heart is mediated by increased oxidative stress and inflammation. Raspberries are rich in polyphenols which may favorably impact enzymes involved in redox homeostasis while also targeting inflammatory signaling. Thus, the objective of this study was to investigate whether raspberry polyphenols could attenuate HF. Sprague Dawley rats consumed a 10% (w/w) raspberry diet for 7 weeks. At week 3, HF was surgically induced via coronary artery ligation. Hemodynamics and morphology of the heart were assessed. Expression of cardiac proteins involved in oxidative stress, inflammation, apoptosis, and remodeling were examined, and histological analysis was conducted. Additionally, human cardiomyocytes were treated with raspberry polyphenol extract (RBPE) followed by CoCl2 to chemically induce hypoxia. Redox status, apoptosis, and mitochondrial dysfunction were measured. Raspberries attenuated reductions in cardiac function and reduced morphological changes which coincided with reduced toll-like receptor (TLR)4 signaling. Reductions in oxidative stress, apoptosis, and remodeling occurred in vivo. Incubation of cardiomyocytes with RBPE attenuated CoCl2-induced oxidative stress and apoptosis despite pronounced hypoxia-inducible factor (HIF)-1α expression. These data indicate that consumption of raspberries can reduce the underlying molecular drivers of HF; thus, leading to the observed improvements in cardiac functional capacity and morphology. This dietary strategy may be an effective alternative strategy for treating HF. However, further investigation into alternative models of HF is warranted.

Prebiotics Together with Raspberry Polyphenolic Extract Mitigate the Development of Nonalcoholic Fatty Liver Diseases in Zucker Rats.

Previous studies suggested that dietary supplementation with prebiotic fructooligosaccharides (FOSs) and polyphenols could mitigate disorders related to the first stage of nonalcoholic fatty liver disease (NAFLD) induced by an obesogenic diet. Therefore, this experiment aimed to address whether the health-promoting potential of raspberry polyphenols together with FOSs can regulate advanced-stage NAFLD in Zucker rats genetically predisposed to develop obesity. The addition of FOSs and raspberry polyphenolic extract to the diet reduced liver fat accumulation and triglyceride, free fatty acid, and total cholesterol levels in the liver. The elevated GSH/GSSG ratio and reduced malondialdehyde content indicated that the liver antioxidant potential was considerably increased. The treatment also lowered the plasma aminotransferase and alkaline phosphatase activities and collagen type IV levels. Insulin levels were decreased, but glucose levels remained constant, indicating greater insulin sensitivity. These changes may result from the upregulation of FXR and AHR receptors in the liver, which are responsible for regulating lipid metabolism and glucose and bile acid synthesis. The reduced bile acid levels in the cecal contents confirmed the activation of liver mechanisms. In conclusion, dietary enrichment with FOSs and raspberry polyphenolic extract has sufficient health-promoting potential to regulate liver metabolism, oxidative stress, and inflammation related to NAFLD development in obese Zucker rats.

Raspberry polyphenols attenuate heart failure by modulating underlying molecular drivers of disease

Introduction: Individuals with heart failure (HF) have a 50% five-year mortality even with modern pharmacological approaches. Thus, alternative therapeutic options are urgently needed. Raspberries are a rich source of polyphenols which have a wide range of bioactive properties and can target cellular pathways involved in HF at the molecular level. Thus, the objective of this study was to investigate the therapeutic potential of raspberry consumption in a model of HF. Hypothesis: We hypothesized that the consumption of raspberries could attenuate the development of HF in rats. Methods: Six-week-old male Sprague Dawley rats consumed either a control diet or a 10% raspberry supplemented diet for three weeks. Rats then underwent a sham operation (control diet only) or permanent ligation of the left anterior descending coronary artery to induce HF (control diet and 10% raspberry diet). Rats continued their diets following surgery for four additional weeks. Echocardiograms were then conducted followed by sacrifice. Hearts were excised for left ventricle protein analysis via Western Blot. Data were analyzed by one-way ANOVA followed by Tukey-Kramer post-hoc analysis. Significance refers to a P-value <0.05. Results: Ejection fraction significantly declined in control diet animals with HF compared to sham (39 ± 6% vs 70 ± 5%); however, the 10% raspberry diet significantly attenuated this reduction (51 ± 3%). There was also a significant increase in left ventricle (LV) mass in control diet animals with HF compared to sham (1,066 ± 140 mg vs 1,670 ± 683 mg), while there were no significant differences in LV mass in the 10% raspberry diet (1,405 ± 285 mg). The nuclear localization of nuclear factor kappa B (NF-κB) was significantly increased in left ventricles of HF animals compared to both sham and the 10% raspberry diet group. The expression of the pro-remodeling cytokine, transforming growth factor (TGF)-β, as well as matrix metalloproteinases (MMP)2 and 9 were significantly increased in HF animals consuming a control diet compared to both sham animals and the 10% raspberry diet group. Phosphorylated ERK1/2, a regulator of cardiac hypertrophic signaling, was expressed in a similar manner. Summary: These data indicate that the consumption of raspberries can reduce the underlying molecular drivers of HF, thus leading to the observed improvements in cardiac functional capacity and morphology. In conclusion, raspberry polyphenols attenuate HF by reducing inflammatory signaling, thus, mitigating proteins involved in cardiac remodeling and hypertrophy. Further investigation in humans is needed to confirm these findings. Agriculture and Food Research Initiative (Grant No. 2019-67017-29257) from USDA-NIFA and a USDA-NIFA predoctoral fellowship (Grant No. 2021-67034-35131). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Dose-Related Regulatory Effect of Raspberry Polyphenolic Extract on Cecal Microbiota Activity, Lipid Metabolism and Inflammation in Rats Fed a Diet Rich in Saturated Fats.

The amount of berry polyphenols required to exert health-promoting effects seems to be difficult to achieve by fresh fruit ingestion, so polyphenol-rich extracts could be considered a dietary alternative. In the present study, laboratory rats were fed high-fat diets supplemented with 0.1 or 0.3% raspberry polyphenols from pomace, with the former dose reflecting the amount of polyphenols consumed with a glass of fresh raspberries. It was hypothesized that beneficial changes in blood and hepatic tissue related to lipid metabolism would accompany both treatments, but the health-promoting effect would be more noticeable with the higher dose of extract. This hypothesis was confirmed, and the high dose of raspberry polyphenols was better than the low dose extract in terms of decreased epididymal white adipose tissue weight, hepatic triglyceride content, PPARγ and SREBP-1c expression in the liver, and plasma IL-6 concentration, as well as increased acetic acid concentration in the cecal digesta. These effects might be partially associated with the enhanced content of ellagitannin and anthocyanin metabolites found in the blood plasma of rats administered the high dose of the extract. The results showed that this extract could be considered a dietary vehicle to provide an amount of raspberry polyphenols that could promote health.

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.

Metabolic fate of black raspberry polyphenols in association with gut microbiota of different origins in vitro

Polyphenols, ubiquitous in plant-originated foods, exhibit multifarious health benefits but are notorious for their low bioavailability. As the majority of polyphenols enter the colon where they are metabolized into the more bioavailable metabolites with multifarious bioactivities, gut microbiota composition is critical for realizing the health benefits of polyphenols. Black raspberries (BRB) are highly abundant in health-promoting but poorly absorbable polyphenols, primarily ellagitannins and anthocyanins. This study aimed to dissect the bilateral interactions between polyphenols and gut microbiotas of diverse origins. Using an optimized extraction procedure, BRB polyphenols were first comprehensively characterized by UHPLC-QTOF-MS/MS. Next, in vitro anaerobic fermentations with microbiota from human adults, infants, rats, and mice were conducted for comparison of phenolic profile (by metabolomics) and microbiota composition (by 16S rDNA sequencing) before and after fermentation. Bioinformatics analysis further revealed unique polyphenol-microbiota interactions and identified several bacterial species that could potentially produce bioactive and bioavailable phenolic metabolites following BRB consumption.

Effects of red raspberry polyphenols and metabolites on the biomarkers of inflammation and insulin resistance in type 2 diabetes: a pilot study.

Berry fruits are rich in polyphenolic compounds (PCs) and may promote health benefits. Anthocyanin (ACN) concentrations of red raspberry (RR) (Rubus idaeus) extracts were 887.6 ± 262.8 μg g-1, consisting mainly of cyanidin-3-sophoroside (C3S) equivalents. To test the efficacy of RR in diabetes treatment, seven patients with type 2 diabetes mellitus (T2DM) were given one oral RR serving (123 g per day) for two weeks. Blood samples were drawn at the baseline (BSL) and post-feeding (PF) periods for phenolic metabolite, inflammation and insulin resistance (IR) biomarker analysis. Two urolithin conjugates, urolithin A glucuronide (Uro-A glur) and urolithin A sulphate (Uro-A sulf) were identified in the PF period in 5 of the 7 patients in nanomolar concentrations (1.6 ± 0.7-63.2 ± 31.2 nM). ACN-derived metabolites such as protocatechuic acid (PCA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were at micromolar levels and were higher during the PF period for diabetics and the levels were as follows: BSL: PCA = 0.6 ± 0.4, DOPAC = 1.2 ± 0.5; PF: PCA = 0.6 ± 0.4, DOPAC = 1.1 ± 0.6. The results revealed significant reductions in high sensitivity C-reactive protein, hsCRP (p = 0.01) and there was a downward trend in IR measured by the homeostatic model assessment of insulin resistance (HOMA-IR, p = 0.0584) in T2DM patients. DOPAC (1-100 μM) failed to stimulate insulin secretion in pancreatic β-cells. The multiplex assay showed variations in the cytokine levels between patients, but differences were not significant. This study demonstrates a potential use of RR in the treatment of inflammation and possibly IR as well in patients with type 2 diabetes.

The Gut Microbiota Regulates the Metabolic Benefits Mediated by Red Raspberry Polyphenols

ObjectivesRed raspberry (RR) polyphenols, including ellagic acid and their gut-derived metabolites, the urolithins, reduce inflammation and improve insulin sensitivity. However, it is unknown whether the gut microbiota is responsible for these health benefits and why certain individuals do not transform ellagic acid into urolithins. Here, we determined the causative role for the microbiome in mediating the health benefits from RR polyphenols using germ-free and conventionalized mouse models of diet-induced obesity. We also tested whether Gordonibacter urolithinfaciens (G. uro), a gut microbe previously shown to metabolize ellagic acid into urolithins, could enhance metabolic benefits when administered as a synbiotic with RR polyphenols. MethodsRR polyphenols were extracted using a macroporous ion-exchange resin column to remove sugars and fibers. C3H/HeN mice with (CVZ) or without a microbiota (GF) were fed either a low fat (LF), high fat (HF), or HF diet with RR polyphenols (HF + RR) for 12 weeks. For synbiotic studies, GF C57BL/6 mice were given a G. uro deficient-microbiome and then fed either a HF or HF + RR diet plus 20% fructose water with or without G. uro for 7 weeks. ResultsFeeding a HF diet increased body weight and fat mass for both GF and CVZ mice compared to feeding a LF diet (P < 0.05). Feeding a HF diet with RR polyphenols significantly decreased visceral adipose tissue and liver triglycerides (P < 0.05) compared to a HF control diet in CVZ but not GF mice. G. uro administration to mice receiving a HF diet and fructose water significantly reduced body weight, body fat percentage, fasting blood glucose, and subcutaneous adipose tissue mass as well as increased ileal tight junction protein gene expression (P < 0.05) compared to controls. Notably, mice supplemented with both G. uro and RR polyphenols experienced no metabolic improvements compared to controls (P < 0.05). ConclusionsOur results demonstrate that the microbiome is required for mediating RR polyphenol metabolic benefits. Supplementation of G. uro improved metabolic health; however, those beneficial effects were abrogated in the presence of RR polyphenols. Together, these results highlight the importance of considering specific diet-microbiota interactions when developing foods for preventing and treating obesity-related diseases. Funding SourcesUSDA NIFA.

Fructo-Oligosaccharides and Pectins Enhance Beneficial Effects of Raspberry Polyphenols in Rats with Nonalcoholic Fatty Liver.

In recent years, nonalcoholic fatty liver disorders have become one of the most common liver pathologies; therefore, it is necessary to investigate the dietary compounds that may support the regulation of liver metabolism and related inflammatory processes. The present study examines the effect of raspberry polyphenolic extract (RE) combined with fructo-oligosaccharides (FOSs) or pectins (PECs) on caecal microbial fermentation, liver lipid metabolism and inflammation in rats with fatty liver induced by an obesogenic diet. The combination of RE with FOSs or PECs reduced the production of short-chain fatty acids in the caecum. RE combined with FOSs exerted the most favourable effects on liver lipid metabolism by decreasing liver fat, cholesterol, triglyceride content and hepatic steatosis. RE and FOSs reduced lobular and portal inflammatory cell infiltration and IL-6 plasma levels. These effects might be related to a decrease in the hepatic expressions of PPARγ and ANGPTL4. In conclusion, PECs and FOSs enhanced the effects of RE against disorders related to nonalcoholic fatty liver; however, the most effective dietary treatment in the regulation of liver lipid metabolism and inflammation caused by an obesogenic diet was the combination of RE with FOSs.

Differential Effects of Whole Red Raspberry Polyphenols and Their Gut Metabolite Urolithin A on Neuroinflammation in BV-2 Microglia.

Whole red raspberry polyphenols (RRW), including ellagic acid, and their gut-derived metabolite, urolithin A (UroA), attenuate inflammation and confer health benefits. Although results from recent studies indicate that polyphenols and UroA also provide neuroprotective effects, these compounds differ in their bioavailability and may, therefore, have unique effects on limiting neuroinflammation. Accordingly, we aimed to compare the neuroprotective effects of RRW and UroA on BV-2 microglia under both 3 h and 12 and 24 h inflammatory conditions. In inflammation induced by lipopolysaccharide (LPS) and ATP stimulation after 3 h, RRW and UroA suppressed pro-inflammatory cytokine gene expression and regulated the JNK/c-Jun signaling pathway. UroA also reduced inducible nitric oxide synthase gene expression and promoted M2 microglial polarization. During inflammatory conditions induced by either 12 or 24 h stimulation with LPS, UroA—but not RRW—dampened pro-inflammatory cytokine gene expression and suppressed JNK/c-Jun signaling. Taken together, these results demonstrate that RRW and its gut-derived metabolite UroA differentially regulate neuroprotective responses in microglia during 3 h versus 12 and 24 h inflammatory conditions.

Raspberry Polyphenol Extract Decreases NF-kB and IL-6 Expression in Lipopolysaccharide (LPS)-Induced RAW 264.7 Macrophages

Abstract Objectives To investigate whether raspberry polyphenol extract attenuates the inflammatory response induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Methods Raspberry polyphenol extract was prepared using methanolic extraction, followed by solvent evaporation and freeze-drying. RAW 264.7 macrophages were treated with 0, 50, 100, 200 and 400 μg/ml of raspberry polyphenol extract in six-well plates. After 2 h, cells were then treated with 100 ng/ml of LPS for 6 h. Cells were collected for protein expression analysis of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and inflammatory cytokines, i.e., interleukin (IL)-6 and IL-1β, via western blot. Results were analyzed using ANOVA followed by Tukey-Kramer post-hoc test. Results As expected, LPS significantly increased NF-kB compared to control (P &amp;lt; 0.0001). Pre-treatment with 400 μg/ml raspberry polyphenol extract significantly decreased phosphorylation of NF-kB in LPS stimulated cells (0.71 ± 0.03 vs. 1.00 ± 0.00-fold, P = 0.005) compared to LPS alone. LPS treatment significantly increased the expression of IL-6 compared to the control group (P &amp;lt; 0.0001). IL-6 expression was significantly reduced in LPS stimulated macrophages by pre-treatment with 200 and 400 µg/ml of raspberry polyphenol extract (0.49 ± 0.03-fold, P &amp;lt; 0.0001 and 0.33 ± 0.04-fold, P &amp;lt; 0.0001 respectively) compared to LPS alone (1.00 ± 0.00-fold). The expression of the inflammatory cytokine IL-1β was significantly greater than control in LPS-only treated cells (P &amp;lt; 0.0001). However, treatment with 400 μg/ml raspberry polyphenol was able to significantly prevent this effect (0.59 ± 0.1 vs. 1.00 ± 0.00-fold, P = 0.007). Conclusions Results indicate that raspberry polyphenols possess anti-inflammatory properties suggesting a possible role as a complementary and alternative therapy to prevent inflammation. However, in vivo and human studies are needed to confirm this. Funding Sources None.

Red Raspberry Polyphenols Attenuate High-Fat Diet-Driven Activation of NLRP3 Inflammasome and its Paracrine Suppression of Adipogenesis via Histone Modifications.

The authors aim to investigate the mechanisms by which red raspberry (RR) polyphenolic fractions regulate obesity and inflammation with an emphasis on the crosstalk between adipose tissue macrophages (ATM) and adipocyte progenitors. C57BL/6 male mice are fed either a high-fat (HF) diet or an HF diet supplemented with a RR polyphenolic fraction from whole fruit, pulp, or seed. Supplementation with pulp significantly increases energy expenditure and reduces HF-diet-induced obesity and insulin resistance. The pulp, and to a lesser extent, whole polyphenols, decreases the recruitment of ATM, activation of the nod-like receptor protein 3 (NLRP3) inflammasome, and adipocyte hypertrophy, which is associated with epigenetic modulation of adipogenesis (e.g., H3K27Ac, H3K9Ac). Results from an IL-1β reporter assay in J774 macrophages recapitulate the inhibitory role of RR polyphenols on NLRP3 inflammasome activation. Using conditioned media from macrophages, it is demonstrated that RR polyphenols reverse the IL-1β-mediated epigenetic suppression of H3K27Ac in adipocyte progenitor cells. RR polyphenols from pulp and whole fruit serve as an inhibitor for NLRP3 inflammasome activation and an epigenetic modifier to regulate adipogenesis, which confers resistance against diet-induced obesity and metabolic dysfunction.

Red Raspberry Polyphenols Reduce the High Fat Diet-driven Adipocyte Hypertrophy by Suppressing NLRP3 Inflammasome Activation (P08-028-19)

ObjectivesNLRP3 inflammasome is an innate immune machinery for caspase-1 cleavage and IL-1β secretion. Activation of the NLRP3 inflammasome is a metabolic culprit linking adipose inflammation to systemic metabolic dysfunction. Red raspberry (RR) is rich in polyphenols shown to exert protective role against obesity and metabolic syndrome. This study aimed to investigate the impact of RR polyphenols on activation of NLRP3 inflammasome and its metabolic benefits. MethodsThe whole, seed, and pulp RR polyphenols were fractionated and lyophilized. C57BL/6 male mice were assigned 1 of 5 diets of LF (10% total calorie from fat), HF (45% calorie from fat), or HF diet containing RR polyphenols from whole (0.4%), pulp (0.3%) and seed (0.1%) fraction for 12 weeks. Macrophage infiltration and NLRP3 inflammasome activation were determined by macrophage signature gene/protein expression and caspase-1 cleavage in the epididymal fat and stromal vascular fraction. Adipogenic potential was evaluated by epigenetic marks of H3K27Ac in the stromal vascular fraction. IL-1β reporter assay was used to validate the NLRP3 inflammasome activation in vitro. To explore the paracrine effects of IL-1β in regulating adipogenesis, we designed the conditioned medium experiments between macrophages and C3H10T1/2 murine pluripotent stem cells. ResultsThe whole and pulp, but not seed, RR polyphenols significantly reduced the HF-driven weight gain, dyslipidemia, and insulin resistance. Whole or pulp RR polyphenols decreased inflammation, macrophage recruitment, and adipocyte size in epididymal fat compared to HF alone or seed polyphenols. Reduced adipocyte size by whole and pulp polyphenols was linked with 1) reduced NLRP3 inflammasome in the stromal vascular fraction, evidenced by reduced IκBα degradation and caspase-1 cleavage, and 2) augmented new fat cell formation via epigenetic modifications for adipogenesis (i.e., H3K27Ac, H3K9Ac, and H3K4m2). Supporting these in vivo results, RR polyphenol treatment in macrophages not only attenuated IL-1β reporter assay but also reversed the paracrine action of IL-1β in blocking adipogenesis in vitro. ConclusionsBlocking NLRP3 by RR polyphenols is a promising dietary intervention strategy to promote healthy adipose remodeling, preventing adipocyte hypertrophy, fatty acid spillover, and further metabolic complications. Funding SourcesUSDA NIFA.

The Reciprocal Interactions between Red Raspberry Polyphenols and Gut Microbiome Composition: Preliminary Findings

BackgroundRed raspberries (Rubus idaeus L.) contain a variety of polyphenols, principally anthocyanins and ellagitannins. Anthocyanins, undergoing metabolism and biotransformation, are absorbed as methylated, sulphated or glucuronidated parent structures or phenolic acids by gut microbiota. Ellagitannins are hydrolyzed to ellagic acid in the stomach and/or the small intestine and further catabolized to urolithins by gut microbiota. Consistent exposure of certain polyphenols to the gut microbiota may act as prebiotic‐like substances feeding the beneficial gut bacteria and changing the gut microbiome composition and function. The dichotomy between the biotransformation of polyphenols into their metabolites by gut microbiota and the modulation of gut microbiome composition by polyphenols is hypothesized to contribute to positive health outcomes.ObjectivesThe present study examined the regular consumption of red raspberry purée or fructo‐oligosaccharide (FOS) on gut microbiome composition and subsequent bioavailability of red raspberry polyphenols in healthy volunteers.MethodsAn 8‐week pilot study, including two 4‐week chronic treatments and 3 postprandial days, served as a feasibility study and mechanism to collect multiple biological specimens for method development. An ultra high‐performance liquid chromatography (HPLC) coupled with electrospray ionization quadrupole time of flight (QTOF) and triple quadrupole (QQQ) mass spectrometer in positive and negative ion modes were used to identify and quantify the phenolic compounds in red raspberry purée, plasma and urine samples. Fecal samples were used for metagenomic study. The sequencing of the 16S ribosomal RNA gene was utilized to study the gut microbiome composition.ResultsThe red raspberry purée ingested contained 49.30 ± 1.45 mg/100 g fresh weight (FW) anthocyanins and 39.35 ± 1.61 mg/100 g FW ellagitannins. After 4‐week red raspberry purée (125g/d) treatment, the abundance of Firmicutes dropped from 83.66% to 48.98%, whereas that of Bacteroidetes increased markedly from 5.99% to 34.79%. At the genus level, the abundance of Akkermansia increased from 0.65% to 6.20%. After 4‐week FOS (positive control, 8 g/d) treatment, the abundance of Firmicutes dropped from 69.91% to 53.93%, whereas that of Bacteroidetes increased from 19.04% to 36.80%. The effects of gut microbiome composition on red raspberry polyphenols biotransformation and their metabolites will be disclosed upon the analysis of plasma and urine metabolites. The results of the pilot study indicate an expanded study is feasible and warranted with preliminary results suggesting marked changes in the gut microbiota composition we hypothesize to influence polyphenol metabolite profiles and systemic health. All the methods and preliminary results will be applied for an expanded study.Support or Funding InformationProject supported by National Processed Raspberry Council and Investigator (Burton‐Freeman/Edirisinghe) various donor funds.

Bioaccessible (poly)phenol metabolites from raspberry protect neural cells from oxidative stress and attenuate microglia activation

Neuroinflammation is an integral part of the neurodegeneration process inherent to several aging dysfunctions. Within the central nervous system, microglia are the effective immune cells, responsible for neuroinflammatory responses. In this study, raspberries were subjected to in vitro digestion simulation to obtain the components that result from the gastrointestinal (GI) conditions, which would be bioaccessible and available for blood uptake. Both the original raspberry extract and the gastrointestinal bioaccessible (GIB) fraction protected neuronal and microglia cells against H2O2-induced oxidative stress and lipopolysaccharide (LPS)-induced inflammation, at low concentrations. Furthermore, this neuroprotective capacity was independent of intracellular ROS scavenging mechanisms. We show for the first time that raspberry metabolites present in the GIB fraction significantly inhibited microglial pro-inflammatory activation by LPS, through the inhibition of Iba1 expression, TNF-α release and NO production. Altogether, this study reveals that raspberry polyphenols may present a dietary route to the retardation or amelioration of neurodegenerative-related dysfunctions.

Inhibitory Effects of Red Raspberry Polyphenols on Osteoclastogenesis in RANKL‐Stimulated RAW264.7 Murine Macrophages

Osteoclasts and osteoblasts regulate skeletal mass, structure, and strength via their respective roles in resorbing and forming bone. Osteoclasts, the cells associated with breakdown of bone, are stimulated by a cytokine known as RANKL (receptor activator of nuclear factor κB ligand), a member of the tumor necrosis factor (TNF) superfamily. Polyphenols such as flavonoids found in plant‐derived foods have demonstrated anti‐inflammatory effects in various tissues. Red raspberries are a rich source of such polyphenolic compounds. Using mouse macrophage cells (RAW 264.7), we examined whether red raspberry polyphenols (RRP) could inhibit the proliferation and activity of RANKL‐induced osteoclastic cells in a dose‐dependent manner. Tartrate resistant acid phosphatase (TRAP) activity and staining of TRAP positive multinucleated osteoclasts, used as indicators of osteoclast differentiation and activity, decreased in a dose dependent manner with RRP treatment. Although, nitrite concentrations were not influenced by RRP treatment, there was a reduction in interleukin (IL)‐1β and IL‐6 with RPP demonstrating its anti‐inflammatory role in bone cells. Western blot analyses showed a dose‐dependent reduction in expression of inducible nitric oxide synthase (iNOS) protein and bone morphogenetic protein‐2 (BMP‐2) by RRP indicating that the polyphenols act to retrain the RANKL mediated osteoclastogenesis. Overall, these findings suggest that the polyphenols associated with red raspberry would inhibit the negative effects of osteoclasts on bone health. Further investigation is warranted to elucidate the molecular mechanisms by which RRP affect osteoclastogenesis.Support or Funding InformationSupported by funds from the Undergraduate Research Microgrant Program at Texas Woman's University. Lyophilized red raspberry was generously provided by Van Drunen Farms.

Blackberry, raspberry and black raspberry polyphenol extracts attenuate angiotensin II-induced senescence in vascular smooth muscle cells.

Activation of angiotensin II (Ang II) signaling during aging increases reactive oxygen species (ROS) leading to vascular senescence, a process linked to the onset and progression of cardiovascular diseases (CVD). Consumption of fruits and vegetables, particularly berries, is associated with decreased incidence of CVD, which has mainly been attributed to the polyphenol content of these foods. Thus, the objective of this study was to investigate the role of blackberry (BL), raspberry (RB), and black raspberry (BRB) polyphenol extracts in attenuating Ang II-induced senescence in vascular smooth muscle cells (VSMCs) and to determine the molecular mechanisms involved. BL, RB and BRB polyphenol extracts (200 μg ml-1) attenuated Ang II-induced senescence, denoted by decreased number of cells positive for senescence associated β-galactosidase (SA-β-gal) and down-regulation of p21 and p53 expression, which were associated with decreased ROS levels and Ang II signaling. BL polyphenol extract increased superoxide dismutase (SOD) 1 expression, attenuated the up-regulation of Nox1 expression and the phosphorylation of Akt, p38MAPK and ERK1/2 induced by Ang II, and reduced senescence in response to Nox1 overexpression. In contrast, RB and BRB polyphenol extracts up-regulated the expression of SOD1, SOD2, and glutathione peroxidase 1 (GPx1), but exerted no effect on Nox1 expression nor on senescence induced by Nox1 overexpression. BRB reduced signaling similar to BL, while RB was unable to reduce Akt phosphorylation. Furthermore, we demonstrated that inhibition of Akt, p38MAPK and ERK1/2 as well as down-regulation of Nox1 by siRNA prevented senescence induced by Ang II. Our findings indicate that Ang II-induced senescence is attenuated by BL polyphenols through a Nox1-dependent mechanism and by RB and BRB polyphenols in a Nox1-independent manner, likely by increasing the cellular antioxidant capacity.

Sugars and Citric Acid Differently Modulate DPPH Antioxidant Activity in Polyphenol‐rich Fruit Juices

The objective of this study was to further characterize the interactions of citric acid, sorbitol, sucrose on the DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) antioxidant activity of polyphenol‐rich juices. Polyphenols were isolated from aronia, raspberry, apple, grape, and cherry juices. Polyphenols were recombined with various levels of citric acid (0 to 1%, w/v) and sugars (0 to 30%, w/v) and DPPH scavenging was subsequently measured near the IC50 value of polyphenol fractions. Sorbitol and citric acid inhibited DPPH activity up to 15 and 10%, respectively in aronia polyphenols. Sorbitol had differential effects on DPPH activity of juice polyphenols. Sorbitol increased DPPH inhibition by 1, 4, and 5% for cherry, grape and raspberry polyphenols, while it was decreased apple juice by 58.1%. Sucrose reduced DPPH inhibition of apple and grape polyphenols 25 and 29% while it increased by 8.0 and 5.6% for raspberry and cherry polyphenols. Citric acid increased apple and raspberry juice polyphenol antioxidant activity by 7.4 and 11%, but did not affect cherry or grape juice polyphenols. Therefore, common sweeteners and citric acid differentially affect in vitro DPPH antioxidant activity of fruit juice polyphenols. This implies that non‐polyphenol components of fruit juices significantly contribute to a widely‐used in vitro measure of antioxidant capacity.This work was supported by an Undergraduate Research Award to Sarah Kranz from the University of Connecticut Office of Undergraduate Research.

Anti-inflammatory Effects of Polyphenolic-Enriched Red Raspberry Extract in an Antigen-Induced Arthritis Rat Model

The red raspberry ( Rubus idaeus ) fruit contains bioactive polyphenols including anthocyanins and ellagitannins with reported anti-inflammatory properties. This study sought to investigate the cartilage-protecting and anti-inflammatory effects of a polyphenolic-enriched red raspberry extract (RRE; standardized to total polyphenol, anthocyanin, and ellagitannin contents) using (1) an in vitro bovine nasal explant cell culture model and (2) an in vivo adjuvant-induced arthritis rat model. RRE contained 20% total polyphenols (as gallic acid equivalents), 5% anthocyanins (as cyanidin-3-glucoside equivalents), and 9.25% ellagitannins (as ellagic acid equivalents). In the in vitro studies, bovine nasal explants were stimulated with 10 ng/mL IL-1β to induce the release of proteoglycan and type II collagen. On treatment with RRE (50 μg/mL), there was a decrease in the rate of degradation of both proteoglycan and type II collagen. In the in vivo antigen-induced arthritis rat model, animals were gavaged daily with RRE (at doses of 30 and 120 mg/kg, respectively) for 30 days after adjuvant injection (750 μg of Mycobacterium tuberculosis suspension in squalene). At the higher dose, animals treated with RRE had a lower incidence and severity of arthritis compared to control animals. Also, histological analyses revealed significant inhibition of inflammation, pannus formation, cartilage damage, and bone resorption by RRE. This study suggests that red raspberry polyphenols may afford cartilage protection and/or modulate the onset and severity of arthritis.