Cecal succinate elevated by some dietary polyphenols may inhibit colon cancer cell proliferation and angiogenesis

Exploring the therapeutic efficacy of crocetin in oncology: an evidence-based review

With cancer being a leading cause of death globally, there is an urgent need to improve therapeutic strategies and identify effective chemotherapeutics. This study aims to highlight the potential of crocetin, a natural product derived from certain plants, as an anticancer agent. It was  conducted an extensive review of the existing literature to gather and analyze the most recent data on the chemical properties of crocetin and its observed effects in various in vitro and in vivo studies. The study  particularly focused on studies that examined crocetin's impact on cell cycle dynamics, apoptosis, caspases and antioxidant enzyme levels, tumor angiogenesis, inflammation, and overall tumor growth. Crocetin exhibited diverse anti-tumorigenic activities including inhibition of tumor cell proliferation, apoptosis induction, angiogenesis suppression, and potentiation of chemotherapy. Multiple cellular and molecular pathways such as the PI3K/Akt, MAPK and NF-κB were modulated by it. Crocetin demonstrates promising anti-cancer properties and offers potential as an adjunctive or alternative therapy in oncology. More large-scale, rigorously designed clinical trials are needed to establish therapeutic protocols and ascertain the comprehensive benefits and safety profile of crocetin in diverse cancer types.

Unravelling Effects of Rosemary (Rosmarinus officinalis L.) Extract on Hepatic Fat Accumulation and Plasma Lipid Profile in Rats Fed a High-Fat Western-Style Diet

The objective of the study was to investigate the preventive effect on obesity-related conditions of rosemary (Rosmarinus officinalis L.) extract (RE) in young, healthy rats fed a high-fat Western-style diet to complement the existing knowledge gap concerning the anti-obesity effects of RE in vivo. Sprague Dawley rats (71.3 ± 0.46 g) were fed a high-fat Western-style diet (WD) or WD containing either 1 g/kg feed or 4 g/kg feed RE for six weeks. A group fed standard chow served as a negative control. The treatments did not affect body weight; however, the liver fat percentage was reduced in rats fed RE, and NMR analyses of liver tissue indicated that total cholesterol and triglycerides in the liver were reduced. In plasma, HDL cholesterol was increased while triglycerides were decreased. Rats fed high RE had significantly increased fasting plasma concentrations of Glucagon-like peptide-1 (GLP-1). Proteomics analyses of liver tissue showed that RE increased enzymes involved in fatty acid oxidation, possibly associated with the higher fasting GLP-1 levels, which may explain the improvement of the overall lipid profile and hepatic fat accumulation. Furthermore, high levels of succinic acid in the cecal content of RE-treated animals suggested a modulation of the microbiota composition. In conclusion, our results suggest that RE may alleviate the effects of consuming a high-fat diet through increased GLP-1 secretion and changes in microbiota composition.

In vitro simulated fecal fermentation of mixed grains on short-chain fatty acid generation and its metabolized mechanism

In vitro simulated digestion and fecal fermentation were performed to investigate the influence of mixed grains on gut microbes. In addition, the key metabolic pathways and enzymes associated with short-chain fatty acids (SCFAs) were explored. The mixed grains exhibited an observable regulatory effect on the composition and metabolism of intestinal microorganisms, especially in probiotics, such as Bifidobacterium spp., Lactobacillus spp., and Faecalibacterium spp. WR (wheat + rye), WB (wheat + highland barley) and WO (wheat + oats) tended to generate lactate and acetate, which are related to Sutterella, Staphylococcus, etc. WQ (wheat + quinoa) induced high propionate and butyrate accumulation by consuming lactate and acetate, mainly through Roseburia inulinivorans, Coprococcus catus and Anaerostipes sp., etc. Moreover, bacteria enriched in different mixed grain groups regulated the expression of pivotal enzymes in metabolic pathways and then affected the generation of SCFAs. These results provide new knowledge on the characteristics of intestinal microbial metabolism in different mixed grain substrates.

Insights on the Role of Polyphenols in Combating Cancer Drug Resistance

Chemotherapy resistance is still a serious problem in the treatment of most cancers. Many cellular and molecular mechanisms contribute to both inherent and acquired drug resistance. They include the use of unaffected growth-signaling pathways, changes in the tumor microenvironment, and the active transport of medicines out of the cell. The antioxidant capacity of polyphenols and their potential to inhibit the activation of procarcinogens, cancer cell proliferation, metastasis, and angiogenesis, as well as to promote the inhibition or downregulation of active drug efflux transporters, have been linked to a reduced risk of cancer in epidemiological studies. Polyphenols also have the ability to alter immunological responses and inflammatory cascades, as well as trigger apoptosis in cancer cells. The discovery of the relationship between abnormal growth signaling and metabolic dysfunction in cancer cells highlights the importance of further investigating the effects of dietary polyphenols, including their ability to boost the efficacy of chemotherapy and avoid multidrug resistance (MDR). Here, it is summarized what is known regarding the effectiveness of natural polyphenolic compounds in counteracting the resistance that might develop to cancer drugs as a result of a variety of different mechanisms.

Dietary Factors Modulating Colorectal Carcinogenesis

The development of colorectal cancer, responsible for 9% of cancer-related deaths, is favored by a combination of genetic and environmental factors. The modification of diet and lifestyle may modify the risk of colorectal cancer (CRC) and prevent neoplasia in up to 50% of cases. The Western diet, characterized by a high intake of fat, red meat and processed meat has emerged as an important contributor. Conversely, a high intake of dietary fiber partially counteracts the unfavorable effects of meat through multiple mechanisms, including reduced intestinal transit time and dilution of carcinogenic compounds. Providing antioxidants (e.g., vitamins C and E) and leading to increased intraluminal production of protective fermentation products, like butyrate, represent other beneficial and useful effects of a fiber-rich diet. Protective effects on the risk of developing colorectal cancer have been also advocated for some specific micronutrients like vitamin D, selenium, and calcium. Diet-induced modifications of the gut microbiota modulate colonic epithelial cell homeostasis and carcinogenesis. This can have, under different conditions, opposite effects on the risk of CRC, through the production of mutagenic and carcinogenic agents or, conversely, of protective compounds. The aim of this review is to summarize the most recent evidence on the role of diet as a potential risk factor for the development of colorectal malignancies, as well as providing possible prevention dietary strategies.

Blueberry Consumption Challenges Hepatic Mitochondrial Bioenergetics and Elicits Transcriptomics Reprogramming in Healthy Wistar Rats

An emergent trend of blueberries’ (BB) “prophylactic” consumption, due to their phytochemicals’ richness and well-known health-promoting claims, is widely scaled-up. However, the benefits arising from BB indiscriminate intake remains puzzling based on incongruent preclinical and human data. To provide a more in-depth elucidation and support towards a healthier and safer consumption, we conducted a translation-minded experimental study in healthy Wistar rats that consumed BB in a juice form (25 g/kg body weight (BW)/day; 14 weeks’ protocol). Particular attention was paid to the physiological adaptations succeeding in the gut and liver tissues regarding the acknowledged BB-induced metabolic benefits. Systemically, BB boosted serum antioxidant activity and repressed the circulating levels of 3-hydroxybutyrate (3-HB) ketone bodies and 3-HB/acetoacetate ratio. Moreover, BB elicited increased fecal succinic acid levels without major changes on gut microbiota (GM) composition and gut ultra-structural organization. Remarkably, an accentuated hepatic mitochondrial bioenergetic challenge, ensuing metabolic transcriptomic reprogramming along with a concerted anti-inflammatory pre-conditioning, was clearly detected upon long-term consumption of BB phytochemicals. Altogether, the results disclosed herein portray a quiescent mitochondrial-related metabolomics and hint for a unified adaptive response to this nutritional challenge. The beneficial or noxious consequences arising from this dietary trend should be carefully interpreted and necessarily claims future research.

Roles of the Polyphenol-Gut Microbiota Interaction in Alleviating Colitis and Preventing Colitis-Associated Colorectal Cancer

Accumulating evidence indicates that the gut microbiota can promote or inhibit colonic inflammation and carcinogenesis. Promotion of beneficial gut bacteria is considered a promising strategy to alleviate colonic diseases including colitis and colorectal cancer. Interestingly, dietary polyphenols, which have been shown to attenuate colitis and inhibit colorectal cancer in animal models and some human studies, appear to reach relatively high concentrations in the large intestine and to interact with the gut microbial community. This review summarizes the modulatory effects of polyphenols on the gut microbiota in humans and animals under healthy and diseased conditions including colitis and colitis-associated colorectal cancer (CAC). Existing human and animal studies indicate that polyphenols and polyphenol-rich whole foods are capable of elevating butyrate producers and probiotics that alleviate colitis and inhibit CAC, such as Lactobacillus and Bifidobacterium. Studies in colitis and CAC models indicate that polyphenols decrease opportunistic pathogenic or proinflammatory microbes and counteract disease-induced dysbiosis. Consistently, polyphenols also change microbial functions, including increasing butyrate formation. Moreover, polyphenol metabolites produced by the gut microbiota appear to have anticancer and anti-inflammatory activities, protect gut barrier integrity, and mitigate inflammatory conditions in cells and animal models. Based on these results, we conclude that polyphenol-mediated alteration of microbial composition and functions, together with polyphenol metabolites produced by the gut microbiota, likely contribute to the protective effects of polyphenols on colitis and CAC. Future research is needed to validate the causal role of the polyphenol-gut microbiota interaction in polyphenols' anti-colitis and anti-CAC effects, and to further elucidate mechanisms underlying such interaction.

RNA-seq revealed the signatures of immunity and metabolism in the Litopenaeus vannamei intestine in response to dietary succinate

The intestine is important for nutrition, metabolism and immunity. Succinate (SA) plays a vital role in the physiological homeostasis of animal intestines. However, the effects of dietary SA on the intestinal immunity and metabolism in shrimp are not clear. In this study, we investigated the immune and metabolic responses in the intestine of Litopenaeus vannamei that were fed diets consisting of different levels of SA: 0 g/kg (Con) and 10 g/kg (SA) for 56 days. The results from a RNA-seq analysis identified 6005 differentially expressed genes (DEGs), including 2728 upregulated genes and 3277 downregulated genes, which were grouped into 312 pathways. The DEGs were most enriched in pathways related to protein synthesis and amino acid metabolism, including "ribosome", "aminoacyl-tRNA biosynthesis", "pyrimidine metabolism", and "arginine and proline metabolism"; additionally, carbohydrate and lipid metabolism pathways were also activated. A large number of immune-related genes were associated with mucus barrier modification, antimicrobial activity, pathogen attachment and recognition, antioxidant activity, and apoptosis. The expression patterns of several candidate genes involved in the immune response and nutrition metabolism were detected by qPCR. This study provides insight into the transcriptomic modulating mechanisms associated with intestinal immunity and the metabolism of L. vannamei in response to the intake of dietary SA.

Demystifying the manipulation of host immunity, metabolism, and extraintestinal tumors by the gut microbiome

The trillions of microorganisms in the gut microbiome have attracted much attention recently owing to their sophisticated and widespread impacts on numerous aspects of host pathophysiology. Remarkable progress in large-scale sequencing and mass spectrometry has increased our understanding of the influence of the microbiome and/or its metabolites on the onset and progression of extraintestinal cancers and the efficacy of cancer immunotherapy. Given the plasticity in microbial composition and function, microbial-based therapeutic interventions, including dietary modulation, prebiotics, and probiotics, as well as fecal microbial transplantation, potentially permit the development of novel strategies for cancer therapy to improve clinical outcomes. Herein, we summarize the latest evidence on the involvement of the gut microbiome in host immunity and metabolism, the effects of the microbiome on extraintestinal cancers and the immune response, and strategies to modulate the gut microbiome, and we discuss ongoing studies and future areas of research that deserve focused research efforts.

Metabolite profile changes and increased antioxidative and antiinflammatory activities of mixed vegetables after fermentation by Lactobacillus plantarum

Fermented vegetables have emerged as prebiotics with various health benefits. However, the possible mechanisms behind their health benefits are unclear. To relate the metabolite profile changes in fermented mixed vegetables with associated health benefits of fermented vegetables, we analyzed the metabolite profiles of mixed vegetables, before and after fermentation by Lactobacillus plantarum, using gas chromatography/time-of-flight-mass spectrometry (GC/TOF-MS). To analyze health benefits of fermented vegetables, antioxidative and antiinflammatory activities were measured using RAW 264.7 cells. Among 78 metabolites identified by GC/TOF-MS in this study, those significantly increased after fermentation include antioxidative and/or antiinflammatory agents such as lactate, 3-phennyllactate, indole-3-lactate, β-hydroxybutyrate, γ-aminobutyrate, and glycerol. These metabolites may have been either newly synthesized or depolymerized from high molecular weight polymers from vegetables during fermentation. This is the first metabolomics study to relate metabolite profile changes with increased health benefits of fermented vegetables.

The Role of Succinate in the Regulation of Intestinal Inflammation

Succinate is a metabolic intermediate of the tricarboxylic acid (TCA) cycle within host cells. Succinate is also produced in large amounts during bacterial fermentation of dietary fiber. Elevated succinate levels within the gut lumen have been reported in association with microbiome disturbances (dysbiosis), as well as in patients with inflammatory bowel disease (IBD) and animal models of intestinal inflammation. Recent studies indicate that succinate can activate immune cells via its specific surface receptor, succinate receptor 1(SUCNR1), and enhance inflammation. However, the role of succinate in inflammatory processes within the gut mucosal immune system is unclear. This review includes current literature on the association of succinate with intestinal inflammation and the potential role of succinate–SUCNR1 signaling in gut immune functions.

Gut-brain signaling in energy homeostasis: the unexpected role of microbiota-derived succinate

In the context of the obesity epidemic, dietary fibers that are found essentially in fruit and vegetables attract more and more attention, since they exert numerous metabolic benefits resulting in the moderation of body weight. Short-chain fatty acids, such as propionate and butyrate, produced through their fermentation by the intestinal microbiota, have long been thought to be the mediators of these benefits. In fact, propionate and butyrate were recently shown to activate intestinal gluconeogenesis, a function exerting metabolic benefits via its capacity of signaling to the brain by gastrointestinal nerves. Recently, succinate, the precursor of propionate in the bacterial metabolism, has also been shown to exert signaling properties, including the activation of intestinal gluconeogenesis.

Metabolite of ellagitannins, urolithin A induces autophagy and inhibits metastasis in human sw620 colorectal cancer cells

Autophagy is an evolutionarily conserved pathway in which cytoplasmic contents are degraded and recycled. This study found that submicromolar concentrations of urolithin A, a major polyphenol metabolite, induced autophagy in SW620 colorectal cancer (CRC) cells. Exposure to urolithin A also dose‐dependently decreased cell proliferation, delayed cell migration, and decreased matrix metalloproteinas‐9 (MMP‐9) activity. In addition, inhibition of autophagy by Atg5‐siRNA, caspases by Z‐VAD‐FMK suppressed urolithin A‐stimulated cell death and anti‐metastatic effects. Micromolar urolithin A concentrations induced both autophagy and apoptosis. Urolithin A suppressed cell cycle progression and inhibited DNA synthesis. These results suggest that dietary consumption of urolithin A could induce autophagy and inhibit human CRC cell metastasis. Urolithins may thus contribute to CRC treatment and offer an alternative or adjunct chemotherapeutic agent to combat this disease.

The Evolving Role of Succinate in Tumor Metabolism: An 18F-FDG-Based Study

In recent years, inherited and acquired mutations in the tricarboxylic acid (TCA) cycle enzymes have been reported in diverse cancers. Pheochromocytomas and paragangliomas often exhibit dysregulation of glucose metabolism, which is also driven by mutations in genes encoding the TCA cycle enzymes or by activation of hypoxia signaling. Pheochromocytomas and paragangliomas associated with succinate dehydrogenase (SDH) deficiency are characterized by high ¹⁸F-FDG avidity. This association is currently only partially explained. Therefore, we hypothesized that accumulation of succinate due to the TCA cycle defect could be the major connecting hub between SDH-mutated tumors and the ¹⁸F-FDG uptake profile. Methods: To test whether succinate modifies the ¹⁸F-FDG metabolic profile of tumors, we performed in vitro and in vivo (small-animal PET/CT imaging and autoradiography) experiments in the presence of succinate, fumarate, and phosphate-buffered saline (PBS) in different cell models. As a control, we also evaluated the impact of succinate on ¹⁸F-fluorocholine uptake and retention. Glucose transporter 1 (GLUT1) immunohistochemistry was performed to assess whether ¹⁸F-FDG uptake correlates with GLUT1 staining. Results: Intratumoral injection of succinate significantly increased ¹⁸F-FDG uptake at 24 h on small-animal PET/CT imaging and autoradiography. No effect of succinate was observed on cancer cells in vitro, but interestingly, we found that succinate caused increased ¹⁸F-FDG uptake by human umbilical vein endothelial cells in a concentration-dependent manner. No significant effect was observed after intratumoral injection of fumarate or PBS. Succinate, fumarate, and PBS have no effect on cell viability, regardless of cell lineage. Intramuscular injection of succinate also significantly increases ¹⁸F-FDG uptake by muscle when compared with either PBS or fumarate, highlighting the effect of succinate on connective tissues. No difference was observed between PBS and succinate on ¹⁸F-fluorocholine uptake in the tumor and muscle and on hind limb blood flow. GLUT1 expression quantification did not significantly differ between the study groups. Conclusion: The present study shows that succinate stimulates ¹⁸F-FDG uptake by endothelial cells, a finding that partially explains the ¹⁸F-FDG metabotype observed in tumors with SDH deficiency. Although this study is an ¹⁸F-FDG-based approach, it provides an impetus to better characterize the determinants of ¹⁸F-FDG uptake in various tumors and their surrounding microenvironment, with a special emphasis on the role of tumor-specific oncometabolites.

Synthesis and Antioxidant Activity of Hydroxytyrosol Alkyl-Carbonate Derivatives

Three procedures have been investigated for the isolation of tyrosol (1) and hydroxytyrosol (2) from a phenolic extract obtained from the solid residue of olive milling. These three methods, which facilitated the recovery of these phenols, were chemical or enzymatic acetylation, benzylation, and carbomethoxylation, and subsequent carbonylation or acetonation reactions. Several new lipophilic alkyl-carbonate derivatives of hydroxytyrosol have been synthesized, coupling the primary hydroxy group of this phenol, through a carbonate linker, using alcohols with different chain lengths. The antioxidant properties of these lipophilic derivatives have been evaluated by different methods and compared with free hydroxytyrosol (2) and also with the well-known antioxidants BHT and α-tocopherol. Three methods were used for the determination of this antioxidant activity: FRAP and ABTS assays, to test the antioxidant power in hydrophilic media, and the Rancimat test, to evaluate the antioxidant capacity in a lipophilic matrix. These new alkyl-carbonate derivatives of hydroxytyrosol enhanced the antioxidant activity of this natural phenol, with their antioxidant properties also being higher than those of the commercial antioxidants BHT and α-tocopherol. There was no clear influence of the side-chain length on the antioxidant properties of the alkyl-carbonate derivatives of 2, although the best results were achieved mainly by the compounds with a longer chain on the primary hydroxy group of this natural phenolic substance.

Polyphenol-based nutraceuticals for the control of angiogenesis: Analysis of the critical issues for human use

Angiogenesis, the formation of new blood-vessel, is crucial in the pathogenesis of several diseases, and thus represents a druggable target for the prevention and treatment of different disorders. It is nowadays well kwon how diet can control cancer development and progression, and how the use of certain diet components can prevent cancer development. Several studies, also from our lab, now indicate that natural plant products including nutraceuticals modulate tumor angiogenesis. In this review, it is reported how phytochemicals, comprising hydroxytyrosol, resveratrol, genistein, curcumin, and the green tea component epigallocatechin-3-gallate among the others, negatively regulate angiogenesis. A single plant-derived compound may affect both endothelial and tumor cells, with the common denominator of anti-inflammatory and radical scavenger activities. Beside these positive features, documented in cellular and animal models, a series of critical issues should be considered from a pharmacological point of view as: what is the best source of bioactive compounds: food and beverages, extracted phytocomplexes, isolated nutraceuticals or synthetic analogues? How is the bioavailability of the compounds of interest in relation to the above source? Is there any biological activity by circulating metabolic derivatives? What is the best formulation, administration route and posology? How safe are in humans? How strong and reliable are the clinical trials designed for their use alone or in combination with conventional chemotherapy? After a dissertation of these critical points, the conclusion can be drawn that novel and effective strategies should be optimized to improve their bioavailability and efficacy, considering their exploitation as chemopreventive and/or curative approaches.

Gallic acid, a phenolic compound, exerts anti-angiogenic effects via the PTEN/AKT/HIF-1α/VEGF signaling pathway in ovarian cancer cells

Gallic acid (GA), a polyphenol, is widely found in numerous fruits and vegetables, particularly in hickory nuts. In the present study, we found that gallic acid, a natural phenolic compound isolated from fruits and vegetables, had a more potent growth inhibitory effect on two ovarian cancer cell lines, OVCAR-3 and A2780/CP70, than the effect on a normal ovarian cell line, IOSE-364. These results demonstrated that GA selectively inhibits the growth of cancer cells. Gene expression was examined by ELISA and western blot analysis, and gene pathways were examined by luciferase assay. It was found that GA inhibited VEGF secretion and suppressed in vitro angiogenesis in a concentration-dependent manner. GA downregulated AKT phosphorylation as well as HIF-1α expression but promoted PTEN expression. The luciferase assay results suggest that the PTEN/AKT/HIF-1α pathway accounts for the inhibitory effect of GA on VEGF expression and in vitro angiogenesis. These findings provide strong support for the high potential of GA in the prevention and therapy of ovarian cancer.

NMR fingerprinting as a tool to evaluate post-harvest time-related changes of peaches, tomatoes and plums

The time-related changes of three agricultural products, coming from two distribution routes, have been followed using NMR fingerprinting to monitor metabolic variations occurring during several days of cold storage. An NMR profiling approach was employed to evaluate the variations in metabolic profile and metabolite content in three different agricultural products highly consumed in Italy (peaches, tomatoes and plums) coming from Tuscanian farms and how they change with time after collection. For each product, we followed the time-related changes during cold storage along three different collection periods. We monitored the variations in metabolic fingerprint and the trend of a set of metabolites, focusing our attention on nutritive and health-promoting metabolites (mainly, essential amino acids and antioxidants) as well as metabolites that contribute to the taste. Concurrently, for comparison, the time-dependent changes of the same kind of products coming from large-scale distribution have been also analyzed under the same conditions. In this second category, only slight variations in the metabolic fingerprint and metabolite levels were seen during cold storage. Unsupervised and supervised multivariate statistics was also employed to enlighten the differences between the three collections. In particular it seems that the metabolic fingerprint of large-scale distribution products is quite similar in the early, middle and late collection, while peaches and plums locally collected are markedly different among the three periods. The metabolic profiles of the agricultural products belonging to these two different distribution routes are intrinsically different, and they show different changes during the time of cold storage.

Culinary herbs and spices: their bioactive properties, the contribution of polyphenols and the challenges in deducing their true health benefits

Herbs and spices have been used for both culinary and medicinal purposes for centuries. Over the last decade, research into their role as contributors of dietary polyphenols, known to possess a number of properties associated with reducing the risk of developing chronic non-communicable diseases, has increased. However, bearing in mind how these foods are consumed, normally in small quantities and in combination with other foods, it is unclear what their true benefit is from a health perspective. The aim of this review is to use the literature to discuss how preparative and digestive processes, bioavailability and interactions between foods may influence the bioactive properties of these foods, and whether or not polyphenols are responsible for these properties. Furthermore, this review aims to highlight the challenges that need to be addressed so as to determine the true benefits of these foods and the mechanisms of action that underpin their purported efficacy.