An Overview of Cancer Chemopreventive Potential and Safety of Proanthocyanidins

Mineral composition, the profile of phenolic compounds, organic acids, sugar and in vitro antioxidant capacity, and antimicrobial activity of organic extracts of Juniperus drupacea fruits

Juniperus drupacea fruit is widely used in traditional and complementary medicine in Turkey for the treatment of different diseases in various forms such as molasses and tar. This study was carried out to evaluate the phenolic compounds, organic acid, sugar, and macro- and micromineral distributions of methanol and water extracts of J. drupace fruit, as well as their antioxidant and antimicrobial potential. For this purpose, total phenolic content by spectrophotometer, phenolics, organic acids, and sugars distributions by HPLC in extracts of J. drupacea fruits, and macro- and micromineral element content by ICP-AES in fruit were determined. 2,2-diphenyl-l-picrylhydrazyl assay (DPPH assay) was used to evaluate in vitro antioxidant activity in extracts. The antimicrobial potential of J. drupacea fruit methanol extract against some gram-positive and gram-negative pathogenic bacteria was evaluated using disk diffusion and minimum inhibitory concentration (MIC) methods. The potassium macroelement and the iron microelement were found at high content in J. drupacea fruit. The total phenolic content in the methanol extracts was higher than the water extracts. Among the individual phenolic compounds, catechin, a flavonoid that was the highest in both extractions, was determined as 300.49 μg/g in methanol extract and 314.88 μg/g in water extract. DPPH scavenging activity was higher in methanol extracts. While the methanol extract of J. drupacea had no-inhibitory effect on the gram-negative bacteria tested, it exhibited a strong inhibition on the gram-positive bacteria Listeria innocua, Listeria monocytogenes, Staphylococcus carnosus, and Enterococcus faecalis.

Nutritional Supplement and Dietary Interventions as a Prophylaxis or Treatment of Sub-Concussive Repetitive Head Impact and Mild Traumatic Brain Injury: A Systematic Review

Mild traumatic brain injury (mTBI) affects 42 to 56 million individuals worldwide annually. Even more individuals are affected by sub-concussive repetitive head impacts (SRHIs). Such injuries may result in significant acute and chronic symptoms. A study of how individuals may adjust or augment their nutritional and dietary habits to prevent cumulative neurotrauma and promote post-injury recovery is necessary. The objective of the current study is to systematically review nutritional and dietary interventions for neurotrauma prevention and mTBI recovery to direct clinical decision-making and identify future areas of research. This systematic review, without a specified time-period, was performed in PubMed, Scopus, Cochrane, CINAHL, and Web of Science followed by a manual search of references. Search strings were generated by a research librarian. Studies were included if they: 1) investigate human subjects with mTBI or SRHI; 2) investigate a supplement/ingredient of dietary supplement sold in the U.S. or dietary intervention without classification as a drug or prohibitive statement against use by the U.S. Food and Drug Administration (FDA); 3) assess a quantifiable outcome; and 4) are published in English in a peer-reviewed journal with an accessible full-length article. Studies were excluded if: 1) the study included non-mTBI or SRHI subjects (e.g., moderate/severe TBI, stroke); 2) mTBI is not assessed separately from moderate/severe mTBI; or 3) the studies that required intracranial hemorrhage. Fifteen studies from 12 unique subject populations met inclusion and exclusion criteria. A total of 1139 mTBI or SRHI subjects were enrolled across intervention arms in the study populations. A total of eight intervention were studied. Omega-3 fatty acid (n-3FA), melatonin, and Pinus radiata were the only interventions examined in multiple studies. Studies included 10 randomized-control trials, three prospective observational studies, and two retrospective observational studies. Seven of the 15 studies had a low risk of bias. Eleven studies reported benefit of the intervention. Strongest evidence supports n-3FA utility for neurotrauma prevention in athletes exposed to SRHI. Both Pinus radiata and melatonin may have benefit for persistent post-concussion symptoms; however, additional multi-center studies are necessary prior to making a definitive conclusion on these supplements' efficacy. Future studies should continue to assess both novel interventions and additional interventions examined in this review to bring additional evidence to the burgeoning field of nutritional and dietary interventions for SRHI and mTBI.

Dietary effect of grape seed proanthocyanidin extract on growth performance, serum biochemical parameters, skin mucosal immune response, and antioxidant capacity in goldfish (Carassius auratus)

A trial was conducted to evaluate the effect of dietary grape seed proanthocyanidin extract (GSPE) on gold fish, Carassius auratus. In this regard, GSPE was added to a basal diet at four levels including 0, 200, 400, and 600 mg/kg to produce four experimental diets including control, GSPE200, GSPE400, and GSPE600. Three hundred and sixty goldfish (3.75 ± 0.1 g) were stocked in twelve 100 L rectangular tanks (30 fish per tank) and fed with the experimental diets three times a day for nine weeks. During the experimental trial, water temperature was 26.7–28.5ºC. The weight gain and specific growth rate in the fish fed with GSPE supplemented diets were higher than the control, meanwhile feed conversion ratio value in these groups decreased compared to the control. Fish fed GSPE-supplemented diets had lower fillet lipid (10-19%), but higher protein levels (7–15%) compared to the control. The levels of serum triglyceride, alanine aminotransferase and aspartate aminotransferase in the fish fed GSPE-supplemented diets were decreased compared to the control group. The highest and lowest levels of serum glucose, and ALP were in the fish fed with control and GSPE600 diets, respectively. The skin mucusal lysozyme activity (24–38%) and protein level (70–96%) were higher in fish fed GSPE-supplemented diets than the control. The highest, and lowest liver antioxidant enzymes including superoxide dismutase, catalase, and gluthatione peroxidase were observed in in GSPE 600, and control groups, respectively. The findings of the present study indicated that supplementing 400 mg/kg GSPE in diet can improve growth and health condition in goldfish.

A ratiometric fluorescent sensing of proanthocyanidins by MnO2 nanosheets simultaneously tuning the photoluminescence of Au/AgNCs and thiamine

By simultaneously regulating the photoluminescence of alloy Au/Ag nanoclusters (NCs) and thiamine (VB1) through MnO₂ nanosheets (MnO₂ NS), a novel ratiometric fluorescent probe (RF-probe) was established for sensitively and selectively monitoring proanthocyanidins (PAs). The introduction of Ag (I) ions could enhance significantly the quantum yields (QYs, 11.1%) of AuNCs based on the synthetic method of UVI (UV irradiation) combined with MWH (microwave heating). MnO₂ NS could quench the fluorescence (FL) of Au/AgNCs mainly coming from Förster resonance energy transfer (FRET), while it could act as a nanozyme catalyst for directly catalyzing the oxidation of VB1 to produce highly fluorescent oxVB1. In the presence of PAs, MnO₂ was reduced to Mn²⁺, which caused that its quenching capacity and oxidase-like activity were vanished, thus the FL of oxVB1 and Au/AgNCs was reduced and recovered. The concentration of PAs could be monitored by the RF-probe with a linear range of 0.27-22.4 μmol L^-1 and corresponding limit of detection (LOD) and limit of quantification (LOQ) were calculated to be 75.9 and 250.5 nmol L^-1. Furthermore, the RF-probe was successfully used for the determination of PAs in mineral water, PAs additive and PAs capsule with satisfactory results compared to the standard HPLC method.

Comparative metabolites profiling of Caryota mitis & Caryota urens via UPLC/MS and isolation of two novel in silico chemopreventive flavonoids

Caryota mitis and Caryota urens (F. Arecaceae) are well reported in Ayurvedic medicine and involved in several edible food products. Herein, the first comparative profiling of their leaf and fruit metabolites of both species via HR-UPLC/PDA/ESI-MS and multivariate data analyses is presented. A total of 142 metabolites were detected with seven reported for the first time in F. Arecaceae and a novel O-caffeoylshikimic acid conjugate. Screening of plants' leaf crude extracts via in vitro DCPIP kinetic assay revealed the induction of phase II cytoprotective enzyme NQO1 by 4.5- to 5-fold versus control, suggestive of potential chemopreventive activity. Two novel sulfated flavonols that is quercetin-3-O-sulfate-4'-O-rhamnosyl (1→6)-β-d-glucoside (F1) and kaempferol-3-O-sulfate-4'-O-rhamnosyl(1→6)-β-d-glucoside (F3) in addition to another five known flavonoids were isolated from C. mitis ethanol extract and identified via MS and NMR spectroscopic techniques. Among isolated compounds, F1 and F3 exhibited the highest docking score as KEAP-1 inhibitors and Nrf2 activators posing them as potential chemopreventive drug leads. PRACTICAL APPLICATIONS: The study extends the usages of this edible less explored Caryota species to a potential cancer chemopreventive action. Guided by the extensive chemical information presented herein, additional uses could be suggested for these plants with 142 identified metabolites including androst-en-diol that has aphrodisiac and muscle building effects. The presented multivariate data analyses could aid phytochemists in plants classification and mapping (chemotaxonomy) since several metabolites are reported herein for the first time either in family or genus.

Change of Serum Metabolome and Cecal Microflora in Broiler Chickens Supplemented With Grape Seed Extracts

Grape seed is rich in vitamin E, flavonoids, and proanthocyanidins and has the potential to be used as an antibiotic substitute in broilers. We investigated the effects of grape seed proanthocyanidin extract (GSPE) on growth performance, immune responses, cecal microflora, and serum metabolism in early stage broilers. Data indicated that GSPE improved broiler growth performance by strengthening antioxidant capacity, enhancing immune responses, and increasing cecal short chain fatty acids. 16S rRNA sequencing indicated that GSPE changed the predominant cecal microflora and induced the metabolism of amino acids, lipids, and carbohydrates. An UPLC-Q-TOF/MS-based metabolomics analysis identified 23 serum metabolites (mainly related to lipid, amino acid, and alkaloid) were extremely changed by GSPE treatment. The correlations between the changes of cecal microflora and serum metabolites in birds fed with GSPE were analyzed. Hence, GSPE potentially provides active ingredients that may be used as antibiotic substitute and reduces environmental pollution by grape by-products.

Natural Tannin Wood Extracts as a Potential Food Ingredient in the Food Industry

Wood extracts are one of the most important natural sources of industrially obtained tannins. Their use in the food industry could be one of the biggest (most important) recent innovations in food science as a result of their multiple (many) possible applications. The use of tannin wood extracts (TWEs) as additives directly added in foods or in their packaging meets an ever-increasing consumer demand for innovative approaches to sustainability. The latest research is focusing on new ways to include them directly in food, to take advantage of their specific actions to prevent individual pathological conditions. The present review begins with the biology of TWEs and then explores their chemistry, specific sensorial properties, and current application in food production. Moreover, this review is intended to cover recent studies dealing with the potential use of TWEs as a starting point for novel food ingredients.

Oligomeric proanthocyanidins (OPCs) from grape seed extract suppress the activity of ABC transporters in overcoming chemoresistance in colorectal cancer cells

Multidrug resistance is a major hindrance in managing cancer. By performing a series of experiments in chemoresistant colorectal cancer cell lines, we demonstrate that oligomeric proanthocyanidins (OPCs) from grape seed extracts can sensitize both acquired (HCT116-FOr cells) and innately chemoresistant (H716 cells) cancer cells to chemotherapeutic drugs, 5-fluorouracil (5FU) and oxaliplatin, by inhibiting adenosine triphosphate-binding cassette (ABC) transporter proteins. When combined with chemotherapeutic drugs, OPCs significantly inhibited growth of the chemoresistant cells (P < 0.05 to < 0.001) and decreased the expression of several key ABC transporters. Moreover, the activity of the ABC transporters was also significantly decreased by OPCs in the cell lines (P < 0.05). We further confirmed that co-treatment with OPCs sensitized the chemoresistant cells to 5FU and oxaliplatin, as observed by improvement in cell cycle arrest, double-strand breaks and p53 accumulation in these cells. In addition, we confirmed that co-administration of OPCs with chemotherapeutic drugs significantly decreased chemoresistant xenograft tumor growth in mice (P < 0.05). Together, our study illuminates the downregulation of multiple ABC transporters as a mechanism by which OPCs overcome chemoresistance in cancer cells and may serve as adjunctive treatments in patients with refractory colorectal cancer.

Effect of grapeseed procyanidins on small intestinal mucosa morphology and small intestinal development in weaned piglets

Context Grapeseed procyanidins (GSP) are widely recognised to have potential biological properties, and dietary supplementation with GSP could reduce diarrhoea incidence in weaned piglets. Aims This trial was conducted to investigate the effect of GSP on small intestinal mucosa morphology and small intestinal development in weaned piglets. Methods Seventy-two weaned piglets were randomly allocated into four dietary groups with three replicate pens per group and six piglets per pen. Each group received one of the following diets: a basal maize–soybean meal diet; or basal diet supplemented with 50, 100 or 150 mg GSP/kg. Small intestinal mucosa morphology and the expression of genes involved in improving small intestinal development were determined. Key results Morphological observations obtained by optical microscopy showed that the villus height of the duodenum and ileum increased in all groups receiving GSP, significantly (P &lt; 0.05) so in the group receiving 100 mg GSP/kg compared with the control group. Crypt depth of the duodenum and ileum in the groups receiving 100 and 150 mg GSP/kg decreased compared with the control group. Similarly, the crypt depth of the jejunum in the group receiving 100 mg GSP/kg was significantly (P &lt; 0.05) lowered. Moreover, the villus height/crypt depth ratio of each small intestinal segment in the group receiving 100 mg GSP/kg increased significantly (P &lt; 0.01). Morphological observations obtained by scanning electron microscopy indicated that dietary supplementation with GSP was favourable for growth of small intestinal villi. Specifically, the villi of the small intestine in the group receiving 100 mg GSP/kg were most closely aligned, most uniform in size and clearest in structure. Furthermore, dietary supplementation with GSP increased the expression of genes encoding epidermal growth factor receptor, insulin-like growth factor 1 (IGF-1) and IGF-1 receptor in the duodenum, the group receiving 100 mg GSP/kg showing a significant (P &lt; 0.05) increase. Conclusions Dietary supplementation with GSP could improve small intestinal mucosa morphology and promote small intestinal development. Dietary supplementation of 100 mg GSP/kg could be recommended for weaned piglets. Implications Dietary supplementation with GSP generated a beneficial role in small intestinal health in weaned piglets.

Nuts

Nuts are fruits composed of two parts: an inedible hard shell and an edible seed. Nuts are known as an energy-dense and nutrient-rich food source. In general, nuts are recognized as a good source of fat, fiber, and protein. Nuts are extremely beneficial parts of any diet since their consumption may lower risk for some diseases, such as cardiovascular diseases and cancer. They are acknowledged for their low glycemic index owning to high unsaturated fat and protein content and relatively low carbohydrate content. They have been shown to increase cognitive function as well.

Natural combination of phenolic glycosides from fruits resists pro-oxidant insults to colon cells and enhances intrinsic antioxidant status in mice

A combination of fresh fruits adequately supplying required nutrients is likely to have better health benefits by virtue of the synergistic/additive effect of its natural constituents. With this view and aiming to obtain phenolic glycosides in combination, fresh apple, grape, orange, pomegranate, and sapota fruit juices were combined and lyophilized. An aqueous extract of this fruit combination (AEFC) had polyphenols as a major constituent (47.36 μg GAE/mL) and LC–MS analysis documented the presence of cyanidin and pallidol 3-O-glucosides, phloridzin, delphinidin-3-O-rutinoside, kaempferol-3-O-pentoside, quercetin-3-O-rutinoside, trans-caffeic acid. Corroborating this, AEFC exhibited significant DPPH and superoxide radical scavenging activities (IC₅₀values 43.63 and 49.01 μg/mL) and protected colon epithelial cells (HCT-15) against H₂O₂ and AAPH induced cell death by 40 and 72.62% and buthionine sulfoximine (BSO) induced GSH depletion by 52.43%. In normal Swiss albino mice, administration of AEFC for over 30 days improved hepatic and renal GPx, SOD, and catalase activities and GSH levels. The study thus suggests the combinatorial effects of natural phenolic glycosides from fruits in resisting oxidative insults and associated disease pathology.

Pro-Apoptotic Effect of Grape Seed Extract on MCF-7 Involves Transient Increase of Gap Junction Intercellular Communication and Cx43 Up-Regulation: A Mechanism of Chemoprevention

Growing evidence suggests dietary antioxidants reduce the risk of several cancers. Grape seeds extracts (GSE) are a rich source of polyphenols known to have antioxidant, chemopreventive and anticancer properties. Herein, we investigated the in vitro effects and putative action mechanisms of a grape seed extract (GSE) on human breast cancer cells (MCF-7). The effects of GSE were evaluated on cell proliferation, apoptosis and gap-junction-mediated cell-cell communications (GJIC), as basal mechanism involved in the promotion stage of carcinogenesis. GSE (0.05-100 μg/mL) caused a significant dose- and time-dependent inhibition of MCF-7 viability and induced apoptotic cell death, as detected by Annexin-V/Propidium Iodide. Concurrently, GSE induced transient but significant enhancement of GJIC in non-communicating MCF-7 cells, as demonstrated by the scrape-loading/dye-transfer (SL/DT) assay and an early and dose-dependent re-localization of the connexin-43 (Cx43) proteins on plasma membranes, as assayed by immunocytochemistry. Finally, real-time-PCR has evidenced a significant increase in cx43 mRNA expression. The results support the hypothesis that the proliferation inhibition and pro-apoptotic effect of GSE against this breast cancer cell model are mediated by the GJIC improvement via re-localization of Cx43 proteins and up-regulation of cx43 gene, and provide further insight into the action mechanisms underlying the health-promoting action of dietary components.

Grape Seed Proanthocyanidin Extract Alleviates AflatoxinB₁-Induced Immunotoxicity and Oxidative Stress via Modulation of NF-κB and Nrf2 Signaling Pathways in Broilers

Aflatoxin B₁ (AFB₁) is a widely spread mycotoxin contaminates food and feed, causing severe oxidative stress damages and immunotoxicity. Grape seed proanthocyanidin (GSPE), a natural antioxidant with wide range of pharmacological and medicinal properties. The goal of the present study was to investigate the protective effects of GSPE against AFB₁-induced immunotoxicity and oxidative stress via NF-κB and Nrf2 signaling pathways in broiler chickens. For the experiment, 240 one-day old Cobb chicks were allocated into four dietary treatment groups of six replicates (10 birds per replicate): 1. Basal diet (control); 2. Basal diet + AFB₁ 1mg/kg contaminated corn (AFB₁); 3. Basal diet + GSPE 250 mg/kg (GSPE); 4. Basal diet + AFB₁ 1 mg/kg + GSPE 250 mg/kg (AFB₁ + GSPE). The results showed that GSPE significantly decreased serum inflammatory cytokines TNF-α, IFN-γ, IL-1β, IL-10, and IL-6 induced by AFB₁. Similarly, GSPE + AFB₁ treated group revealed a significant decrease in mRNA expressions of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β, and IL-6) in the splenic tissue compared to the AFB₁ treatment group. In addition, western blotting results manifested that GSPE treatment normalized the phosphorylation of nuclear factor kappa B (p65) and the degradation of IκBα protein induced by AFB₁. Furthermore, GSPE enhanced the antioxidant defense system through activating the nuclear factor-erythroid-2-related factor (Nrf2) signaling pathway. The mRNA and protein expression level of Nrf2 and its down streaming associated genes were noted up-regulated by the addition of GSPE, and down-regulated in the AFB₁ group. Taken together, GSPE alleviates AFB₁-induced immunotoxicity and oxidative damage by inhibiting the NF-κB and activating the Nrf2 signaling pathways in broiler chickens. Conclusively, our results suggest that GSPE could be considered as a potential natural agent for the prevention of AFB₁-induced immunotoxicity and oxidative damage.

A combination of curcumin and oligomeric proanthocyanidins offer superior anti-tumorigenic properties in colorectal cancer

Combining anti-cancer agents in cancer therapies is becoming increasingly popular due to improved efficacy, reduced toxicity and decreased emergence of resistance. Here, we test the hypothesis that dietary agents such as oligomeric proanthocyanidins (OPCs) and curcumin cooperatively modulate cancer-associated cellular mechanisms to inhibit carcinogenesis. By a series of in vitro assays in colorectal cancer cell lines, we showed that the anti-tumorigenic properties of the OPCs-curcumin combination were superior to the effects of individual compounds. By RNA-sequencing based gene-expression profiling in six colorectal cancer cell lines, we identified the cooperative modulation of key cancer-associated pathways such as DNA replication and cell cycle pathways. Moreover, several pathways, including protein export, glutathione metabolism and porphyrin metabolism were more effectively modulated by the combination of OPCs and curcumin. We validated genes belonging to these pathways, such as HSPA5, SEC61B, G6PD, HMOX1 and PDE3B to be cooperatively modulated by the OPCs-curcumin combination. We further confirmed that the OPCs-curcumin combination more potently suppresses colorectal carcinogenesis and modulated expression of genes identified by RNA-sequencing in mice xenografts and in colorectal cancer patient-derived organoids. Overall, by delineating the cooperative mechanisms of action of OPCs and curcumin, we make a case for the clinical co-administration of curcumin and OPCs as a treatment therapy for patients with colorectal cancer.

Mechanistic insights into anticancer properties of oligomeric proanthocyanidins from grape seeds in colorectal cancer

Although the anticancer properties of oligomeric proanthocyanidins (OPCs) from grape seeds have been well recognized, the molecular mechanisms by which they exert anticancer effects are poorly understood. In this study, through comprehensive RNA-sequencing-based gene expression profiling in multiple colorectal cancer cell lines, we for the first time illuminate the genome-wide effects of OPCs from grape seeds in colorectal cancer. Our data revealed that OPCs affect several key cancer-associated genes. In particular, genes involved in cell cycle and DNA replication were most significantly and consistently altered by OPCs across multiple cell lines. Intriguingly, our in vivo experiments showed that OPCs were significantly more potent at decreasing xenograft tumor growth compared with the unfractionated grape seed extract (GSE) that includes the larger polymers of proanthocyanidins. These findings were further confirmed in colorectal cancer patient-derived organoids, wherein OPCs more potently inhibited the formation of organoids compared with GSE. Furthermore, we validated alteration of cell cycle and DNA replication-associated genes in cancer cell lines, mice xenografts as well as patient-derived organoids. Overall, this study provides an unbiased and comprehensive look at the mechanisms by which OPCs exert anticancer properties in colorectal cancer.

Epigenetics, Nutrition, Disease and Drug Development

Epigenetic mechanisms comprising of DNA methylation, histone modifications and gene silencing by RNA interference have been strongly linked to the development and progression of various diseases. These findings have triggered research on epigenetic functions and signal pathways as targets for novel drug discovery. Dietary intake has also presented significant influence on human health and disease development and nutritional modifications have proven important in prevention, but also the treatment of disease. Moreover, a strong link between nutrition and epigenetic changes has been established. Therefore, in attempts to develop novel safer and more efficacious drugs, both nutritional requirements and epigenetic mechanisms need to be addressed.

Ameliorative Effects of Grape Seed Proanthocyanidin Extract on Growth Performance, Immune Function, Antioxidant Capacity, Biochemical Constituents, Liver Histopathology and Aflatoxin Residues in Broilers Exposed to Aflatoxin B₁

Aflatoxicosis is a grave threat to the poultry industry. Dietary supplementation with antioxidants showed a great potential in enhancing the immune system; hence, protecting animals against aflatoxin B₁-induced toxicity. Grape seed proanthocyanidin extract (GSPE) one of the most well-known and powerful antioxidants. Therefore, the purpose of this research was to investigate the effectiveness of GSPE in the detoxification of AFB₁ in broilers. A total of 300 one-day-old Cobb chicks were randomly allocated into five treatments of six replicates (10 birds per replicate), fed ad libitum for four weeks with the following dietary treatments: 1. Basal diet (control); 2. Basal diet + 1 mg/kg AFB₁ contaminated corn (AFB₁); 3. Basal diet + GSPE 250 mg/kg; (GSPE 250 mg/kg) 4. Basal diet + AFB₁ (1 mg/kg) + GSPE 250 mg/kg; (AFB₁ + GSPE 250 mg/kg) 5. Basal diet + AFB₁ (1mg/kg) + GSPE 500 mg/kg, (AFB₁ + GSPE 500 mg/kg). When compared with the control group, feeding broilers with AFB₁ alone significantly reduced growth performance, serum immunoglobulin contents, negatively altered serum biochemical contents, and enzyme activities, and induced histopathological lesion in the liver. In addition, AFB₁ significantly increased malondialdehyde content and decreased total superoxide dismutase, catalase, glutathione peroxide, glutathione-S transferase, glutathione reductase activities, and glutathione concentration within the liver and serum. The supplementation of GSPE (250 and 500 mg/kg) to AFB₁ contaminated diet reduced AFB₁ residue in the liver and significantly mitigated AFB₁ negative effects. From these results, it can be concluded that dietary supplementation of GSPE has protective effects against aflatoxicosis caused by AFB₁ in broiler chickens.

Proanthocyanidin protects against cisplatin-induced oxidative liver damage through inhibition of inflammation and NF-κβ/TLR-4 pathway

Although cisplatin (CIS) is a highly effective anticancer drug, hepatotoxicity is one of the most common adverse effects associated with its use. Recently, reactive oxygen species (ROS) and inflammation are suggested to be key factors in the pathophysiology of CIS-induced acute liver damage. The aim of this study is to investigate the possible protective effect of proanthocyanidin (PRO) against CIS-induced acute hepatotoxicity. Rats were divided into four groups: 1, Control; 2, PRO; 3, CIS; and 4, PRO + CIS. Biochemical studies and histopathology were used to assess liver damage. ROS, inflammatory cytokines, nuclear factor kappa beta (NF-κβ), inducible cyclooxygenase enzyme (COX-2), inducible nitric oxide synthase (iNOS), toll-like receptor-4 (TLR-4) gene expression, and apoptotic markers were also assessed. PRO pretreatment protected the liver against CIS-induced toxicity as indicated by decreased plasma levels of liver function enzymes and the normal liver histopathology observed in the PRO + CIS group. PRO pretreatment also diminished indicators of oxidative stress in the liver, including nitric oxide (NO) and malondialdehyde (MDA). It also increased the antioxidants, reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) in the liver. Plasma interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) were all reduced. Liver gene expression of NF-κβ, COX-2, iNOS, and TLR-4 were all downregulated. Furthermore, PRO administration downregulated the liver expression of the apoptotic marker, Bax, while upregulated the antiapoptotic marker, Bcl2. In conclusion, our results revealed that PRO may protect against CIS-induced acute liver damage mainly through inhibition of ROS, inflammation, and apoptosis.

Proanthocyanidins and hydrolysable tannins: occurrence, dietary intake and pharmacological effects

Tannins are a heterogeneous group of high MW, water-soluble, polyphenolic compounds, naturally present in cereals, leguminous seeds and, predominantly, in many fruits and vegetables, where they provide protection against a wide range of biotic and abiotic stressors. Tannins exert several pharmacological effects, including antioxidant and free radical scavenging activity as well as antimicrobial, anti-cancer, anti-nutritional and cardio-protective properties. They also seem to exert beneficial effects on metabolic disorders and prevent the onset of several oxidative stress-related diseases. Although the bioavailability and pharmacokinetic data for these phytochemicals are still sparse, gut absorption of these compounds seems to be inversely correlated with the degree of polymerization. Further studies are mandatory to better clarify how these molecules and their metabolites are able to cross the intestinal barrier in order to exert their biological properties. This review summarizes the current literature on tannins, focusing on the main, recently proposed mechanisms of action that underlie their pharmacological and disease-prevention properties, as well as their bioavailability, safety and toxicology.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Intervention of Grape Seed Proanthocyanidin Extract on the Subchronic Immune Injury in Mice Induced by Aflatoxin B1

The aim was to investigate the prevention of grape seed proanthocyanidin extract (GSPE) on the subchronic immune injury induced by aflatoxin B1 (AFB1) and the possible ameliorating effect of GSPE in mice. The subchronic AFB1-induced immune injury mice model was set up with the continuous administration of 100 μg/kg body weight (BW) AFB1 for six weeks by intragastric administration. Then, intervention with different doses (50 and 100 mg/kg BW) of GSPE was conducted on mice to analyze the changes of body weight, immune organ index, antioxidant capability of spleen, serum immunoglobulin content, and the expression levels of inflammatory cytokines. The prevention of GSPE on the immune injury induced by AFB1 was studied. The GSPE could relieve the AFB1-induced reduction of body weight gain and the atrophy of the immune organ. The malondialdehyde (MDA) level of the spleen in the AFB1 model group significantly increased, but levels of catalase (CAT), glutathione (GSH), glutathione peroxidase (GSH-P_X), and superoxide dismutase (SOD) significantly decreased. The GSPE could significantly inhibit the oxidative stress injury of the spleen induced by AFB1. AFB1 exposure could not significantly change the contents of IgA, IgG, or IgM. AFB1 significantly improved the expression of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ). Additionally, GSPE could decrease the expression of these four proinflammatory factors to different degrees and inhibit the inflammatory reaction of mice. The results suggest that GSPE alleviates AFB1-induced oxidative stress and significantly improves the immune injury of mice induced by AFB1.

Reversed-phase liquid chromatographic analysis of hydrophobic interaction between proanthocyanidins and a C8-alkyl compound in aqueous solution

Structural and physicochemical properties of oligomeric flavan-3-ols (proanthocyanidins) in aqueous solution were investigated by spectrometric and reversed-phase (RP) HPLC analyses. Circular dichroism and fluorescence spectra of (–)-epicatechin (EC) oligomers linked through C-4 to C-8 interflavan bonds showed that EC oligomers larger than dimers formed a stable secondary structure in water. These EC oligomers are water-soluble hydrophilic compounds, whereas the oligomers were strongly retained by a C8-alkyl stationary phase under conventional RP-HPLC conditions. In a further C8-HPLC study, the hydrophobic interaction between EC oligomers and 1-octanesulfonic acid sodium salt (OSA Na) added to the mobile phase was quantitatively evaluated based on the relationship between the logarithm of the retention factor of the solute and the OSA Na concentration in the mobile phase. The strength values of the hydrophobic interaction of EC oligomers larger than dimers were the highest of 22 tested polyphenolic standards.

Quantification of tannins and related polyphenols in commercial products of tormentil (Potentilla tormentilla)

INTRODUCTION

Potentilla tormentilla has many biological and pharmacological properties and can be used as an ingredient of some herbal medicines or beverages.

OBJECTIVE

The aim of this study was to evaluate the content of individual polyphenols, especially condensed and hydrolysable tannins in commercially available tormentil rhizomes and tinctures using chromatographic methods.

METHODS

A quantitative analysis (HPLC-PDA) was preceded by qualitative studies (UPLC-qTOF-MS/MS) and the isolation (CC) of the major tannin compounds.

RESULTS

The tested plant material is characterised by a high content of tannins and related polyphenols, i.e. in rhizomes even at the level above 20% and in tinctures above 2%. The main components of tormentil rhizomes are procyanidin B3 (mean ~ 3.6%), procyanidin C2 (mean ~ 2.8%), agrimoniin (mean ~ 2.5%), 3-O-galloylquinic acid (mean ~ 1.7%), catechin (mean ~ 1.6%), other flavan-3-ol oligomers (mean ~ 0.5-1.1) and laevigatins (mean ~ 0.2-0.6%). Free ellagic acid and glycosides of ellagic and methylellagic acids are secondary components.

CONCLUSIONS

Underground parts of tormentil are a source of oligomeric proanthocyanidins and ellagitannins, but in smaller quantity of gallotannins. Monogalloylquinic acids are new identified compounds, which had not been described in Potentilla tormentilla before we started our research. In the analysed tormentil tinctures agrimoniin concentration is lower in relation to other tannins.

Epigenetic activities of flavonoids in the prevention and treatment of cancer

Aberrant epigenetic modifications are described in an increasing number of pathological conditions, including neurodegenerative diseases, cardiovascular diseases, diabetes mellitus type 2, obesity and cancer. The general reversibility of epigenetic changes makes them an attractive and promising target e.g. in the treatment of cancer. Thus, a growing number of epigenetically active compounds are currently tested in clinical trials for their therapeutic potential. Interestingly, many phytochemicals present in plant foods, particularly flavonoids, are suggested to be able to alter epigenetic cellular mechanisms. Flavonoids are natural phenol compounds that form a large group of secondary plant metabolites with interesting biological activities. They can be categorized into six major subclasses, which display diverse properties affecting the two best characterized epigenetic mechanisms: modulation of the DNA methylation status and histone acetylation. High dietary flavonoid intake has strongly been suggested to reduce the risk of numerous cancer entities in a large body of epidemiological studies. Established health-promoting effects of diets rich in fruit and vegetables are faced by efforts to use purified flavonoids as supplements or pharmaceuticals, whereupon data on the latter applications remain controversial. The purpose of this review is to give an overview of current research on flavonoids to further elucidate their potential in cancer prevention and therapy, thereby focusing on their distinct epigenetic activities.

Analysis of oligomer proanthocyanidins in different barley genotypes using high-performance liquid chromatography-fluorescence detection-mass spectrometry and near-infrared methodologies

Proanthocyanidins are a class of polyphenols present in many foodstuffs (i.e., tea, cocoa, berries, etc.) that may reduce the risk of several chronic diseases. Barley, with sorghum, rice, and wheat, are the only cereals that contain these compounds. Because of that, two barley genotypes, named waxy and non-waxy, were analyzed by normal-phase high-performance liquid chromatography-fluorescence detection-mass spectrometry (NP-HPLC-FLD-MS). Total proanthocyanidin content ranged between 293.2 and 652.6 μg/g of flour. Waxy samples reported the highest content (p < 0.05) of proanthocyanidins. Dimer compounds were the principal proanthocyanidin constituents of barley samples. Moreover, the possibility to use near-infrared (NIR) spectroscopy as a rapid method to discriminate between waxy and non-waxy samples and to predict quantitatively proanthocyanidins in barley samples was evaluated. Partial least squares (PLS) models were built to predict the proanthocyanidin constituent, obtaining determination coefficients (R(2)) ranging from 0.92 to 0.97, in test set validation. Because of that, this study highlights that NIR spectroscopy technology with multivariate calibration analysis could be successfully applied as a rapid method to determine proanthocyanidin content in barley.

Epigenetics and nutritional environmental signals

All terrestrial life is influenced by multi-directional flows of information about its environment, enabling malleable phenotypic change through signals, chemical processes, or various forms of energy that facilitate acclimatization. Billions of biological co-inhabitants of the earth, including all plants and animals, collectively make up a genetic/epigenetic ecosystem by which adaptation/survival (inputs and outputs) are highly interdependent on one another. As an ecosystem, the solar system, rotation of the planets, changes in sunlight, and gravitational pull influence cyclic epigenetic transitions and chromatin remodeling that constitute biological circadian rhythms controlling senescence. In humans, adverse environmental conditions such as poverty, stress, alcohol, malnutrition, exposure to pollutants generated from industrialization, man-made chemicals, and use of synthetic drugs can lead to maladaptive epigenetic-related illnesses with disease-specific genes being atypically activated or silenced. Nutrition and dietary practices are one of the largest facets in epigenetic-related metabolism, where specific "epi-nutrients" can stabilize the genome, given established roles in DNA methylation, histone modification, and chromatin remodeling. Moreover, food-based "epi-bioactive" constituents may reverse maladaptive epigenetic patterns, not only prior to conception and during fetal/early postnatal development but also through adulthood. In summary, in contrast to a static genomic DNA structure, epigenetic changes are potentially reversible, raising the hope for therapeutic and/or dietary interventions that can reverse deleterious epigenetic programing as a means to prevent or treat major illnesses.

Anti-carcinogenic effects of non-polar components containing licochalcone A in roasted licorice root

BACKGROUND/OBJECTIVE

Licorice has been shown to possess cancer chemopreventive effects. However, glycyrrhizin, a major component in licorice, was found to interfere with steroid metabolism and cause edema and hypertension. The roasting process of licorice modifies the chemical composition and converts glycyrrhizin to glycyrrhetinic acid. The purpose of this study was to examine the anti-carcinogenic effects of the ethanol extract of roasted licorice (EERL) and to identify the active compound in EERL.

MATERIALS/METHODS

Ethanol and aqueous extracts of roasted and un-roasted licorice were prepared. The active fraction was separated from the methylene chloride (MC)-soluble fraction of EERL and the structure of the purified compound was determined by nuclear magnetic resonance spectroscopy. The anti-carcinogenic effects of licorice extracts and licochalcone A was evaluated using a MTT assay, Western blot, flow cytometry, and two-stage skin carcinogenesis model.

RESULTS

EERL was determined to be more potent and efficacious than the ethanol extract of un-roasted licorice in inhibiting the growth of DU145 and MLL prostate cancer cells, as well as HT-29 colon cancer cells. The aqueous extracts of un-roasted and roasted licorice showed minimal effects on cell growth. EERL potently inhibited growth of MCF-7 and MDA-MB-231 breast, B16-F10 melanoma, and A375 and A2058 skin cancer cells, whereas EERL slightly stimulated the growth of normal IEC-6 intestinal epithelial cells and CCD118SK fibroblasts. The MC-soluble fraction was more efficacious than EERL in inhibiting DU145 cell growth. Licochalcone A was isolated from the MC fraction and identified as the active compound of EERL. Both EERL and licochalcone A induced apoptosis of DU145 cells. EERL potently inhibited chemically-induced skin papilloma formation in mice.

CONCLUSIONS

Non-polar compounds in EERL exert potent anti-carcinogenic effects, and that roasted rather than un-roasted licorice should be favored as a cancer preventive agent, whether being used as an additive to food or medicine preparations.

Antioxidant properties of proanthocyanidins attenuate carbon tetrachloride (CCl4)-induced steatosis and liver injury in rats via CYP2E1 regulation

Liver steatosis is characterized by lipid dysregulation and fat accumulation in the liver and can lead to oxidative stress in liver. Since proanthocyanidins are present in plant-based foods and have powerful antioxidant properties, we investigated whether proanthocyanidins can prevent oxidative stress and subsequent liver injury. Carbon tetrachloride (CCl4) treatment can cause steatosis in rats that models both alcoholic and non-alcoholic fatty liver disease in humans. We pre-treated rats by oral administration of proanthocyanidins extracted from grape seeds 7 days prior to intragastrically administering CCl4. Proanthocyanidin treatment continued for an additional 2 weeks, after which time liver and serum were harvested, and mediators of liver injury, oxidative stress, and histological features were evaluated. CCl4-treated rats exhibited significant increases in the following parameters as compared to non-treated rats: fat droplets in the liver, liver injury (ALT, AST), and DNA damage (8-OHdG). Additionally, CCl4 treatment decreased antioxidant enzymes SOD, GSH, GPX, and CAT in the liver due to their rapid depletion after battling against oxidative stress. Compared to CCl4-treated rats, treatment with proanthocyanidins effectively suppressed lipid accumulation, liver injury, DNA damage, as well as restored antioxidant enzyme levels. Further investigation revealed that proanthocyanidins treatment also inhibited expression of CYP2E1 in liver, which prevented the initial step of generating free radicals from CCl4. The data presented here show that treatment with orally administered proanthocyanidins prevented liver injury in the CCl4-induced steatosis model, likely through exerting antioxidant actions to suppress oxidative stress and inhibiting the free radical-generating CYP2E1 enzyme.

Usnic acid inhibits growth and induces cell cycle arrest and apoptosis in human lung carcinoma A549 cells

Usnic acid (UA) is a secondary metabolite abundantly found in lichens. Some studies have shown the anticancer potential of UA; however, its efficacy and associated mechanisms are yet to be fully explored. Herein, we assessed the anticancer potency and associated molecular alterations by UA in human lung carcinoma A549 cells. UA treatment (25-100 μM) for 24 and 48 h decreased total cell number by 39-67% (P < 0.01) and 68-89% (P < 0.001), respectively, and enhanced cell death by up to twofold and eightfold (P < 0.001), respectively. UA (1-10 μM) also significantly (P < 0.001) suppressed colony formation of A549 cells. The cell growth inhibition was associated with cell cycle arrest at G0/ G1 phase. UA decreased the expression of cyclin-dependent kinase (CDK)4, CDK6, and cyclin D1 and increased the expression of CDK inhibitor (CDKI) p21/cip1 protein. While examining the cell death associated molecular changes, we observed that UA induces mitochondrial membrane depolarization and led to more than twofold increase (P < 0.01) in apoptotic cells. The apoptotic effect of UA was accompanied by enhanced poly(ADP-ribose) polymerase cleavage. This study shows that UA inhibits cell growth involving G0/G1 phase cell cycle arrest and induces cell death via mitochondrial membrane depolarization and induction of apoptosis in human lung carcinoma cells.

Dietary agents in cancer prevention: an immunological perspective

Skin cancer is the most common form of cancer diagnosed in the United States. Exposure to solar ultraviolet (UV) radiations is believed to be the primary cause for skin cancer. Excessive UV radiation can lead to genetic mutations and damage in the skin's cellular DNA that in turn can lead to skin cancer. Lately, chemoprevention by administering naturally occurring non-toxic dietary compounds has proven to be a potential strategy to prevent the occurrence of tumors. Attention has been drawn toward several natural dietary agents such as resveratrol, one of the major components found in grapes, red wines, berries and peanuts, proanthocyanidins from grape seeds, (-)-epigallocatechin-3-gallate from green tea, etc. However, the effect these dietary agents have on the immune system and the immunological mechanisms involved therein are still being explored. In this review, we shall focus on the role of key chemopreventive agents on various immune cells and discuss their potential as antitumor agents with an immunological perspective.