Amandeep K. Sandhu

Antioxidant Capacity, Phenolic Content, and Profiling of Phenolic Compounds in the Seeds, Skin, and Pulp of Vitis rotundifolia (Muscadine Grapes) As Determined by HPLC-DAD-ESI-MSn

The objective of this study was to determine and compare the total phenolic content and antioxidant capacity in the seeds, skin, and pulp of eight cultivars of Florida-grown muscadine grapes and to identify the phenolic compounds in these respective portions. Total phenolic contents were determined colorimetrically using Folin-Ciocalteu reagent, and antioxidant capacity was determined by oxygen radical absorbance capacity (ORAC). High-performance liquid chromatography equipped with diode array (HPLC-DAD) and electrospray ionization mass spectrometric detection (ESI-MS(n)) was used to identify the phenolic compounds in the seeds, skin, and pulp of muscadine grapes. The total phenolic content and antioxidant capacity, based on fresh weight, were highest in seeds followed by skin and pulp. On average, 87.1, 11.3, and 1.6% of phenolic compounds were present in seeds, skin, and pulp, respectively. A total of 88 phenolic compounds of diverse structures were tentatively identified in muscadines, which included 17 in the pulp, 28 in the skin, and 43 in the seeds. Seventeen compounds were identified for the first time in muscadine grapes. The compounds identified in seeds included hydrolyzable tannins, flavan-3-ols and condensed tannins, ellagic acid derivatives, and quercetin rhamnoside. The skin contained hydrolyzable tannins, flavonoids, including anthocyanin 3,5-diglucosides, quercetin, myricetin, and kaempferol glycosides.

Adsorption/Desorption Characteristics and Separation of Anthocyanins from Muscadine (Vitis rotundifolia) Juice Pomace by Use of Macroporous Adsorbent Resins

In this study, the adsorption/desorption characteristics of anthocyanins on five Amberlite resins (FPX-66, XAD-7HP, XAD-16N, XAD-1180, and XAD-761) were evaluated. FPX-66 and XAD-16N showed the highest adsorption and desorption capacities and ratios for anthocyanins from muscadine pomace extract, while XAD-7HP had the lowest adsorption and desorption capacities and ratios. On the basis of static adsorption and desorption tests, three resins (FPX-66, XAD-16N, and XAD-1180) were selected for adsorption kinetics and isotherms. The adsorption mechanism was better explained by the pseudo-first-order kinetics for FPX-66 and XAD-16N; however, for XAD-1180, pseudo-second-order kinetics was the most suitable model. The experimental data fitted best to Langmuir isotherm model for all three resins. Dynamic testing was done on a column packed with FPX-66 resin and breakthrough volume was reached at 17 bed volumes of muscadine pomace water extract during adsorption. Three bed volumes of aqueous ethanol (70%) resulted in complete desorption. Resin adsorption resulted in a concentrated pomace extract that contained 13% (w/w) anthocyanins with no detectable sugars.

Red Raspberries and Their Bioactive Polyphenols: Cardiometabolic and Neuronal Health Links

Diet is an essential factor that affects the risk of modern-day metabolic diseases, including cardiovascular disease, diabetes mellitus, obesity, and Alzheimer disease. The potential ability of certain foods and their bioactive compounds to reverse or prevent the progression of the pathogenic processes that underlie these diseases has attracted research attention. Red raspberries (Rubus idaeus L.) are unique berries with a rich history and nutrient and bioactive composition. They possess several essential micronutrients, dietary fibers, and polyphenolic components, especially ellagitannins and anthocyanins, the latter of which give them their distinctive red coloring. In vitro and in vivo studies have revealed various mechanisms through which anthocyanins and ellagitannins (via ellagic acid or their urolithin metabolites) and red raspberry extracts (or the entire fruit) could reduce the risk of or reverse metabolically associated pathophysiologies. To our knowledge, few studies in humans are available for evaluation. We review and summarize the available literature that assesses the health-promoting potential of red raspberries and select components in modulating metabolic disease risk, especially cardiovascular disease, diabetes mellitus, obesity, and Alzheimer disease-all of which share critical metabolic, oxidative, and inflammatory links. The body of research is growing and supports a potential role for red raspberries in reducing the risk of metabolically based chronic diseases.

Muscadine Grape (Vitis rotundifolia) and Wine Phytochemicals Prevented Obesity-Associated Metabolic Complications in C57BL/6J Mice

The objective of this study was to determine the effects of muscadine grape or wine (cv. Noble) phytochemicals on obesity and associated metabolic complications. Muscadine grape or wine phytochemicals were extracted using Amberlite FPX66 resin. Male C57BL/6J mice were given a low-fat diet (LF, 10% kcal fat), high-fat diet (HF, 60% kcal fat), HF + 0.4% muscadine grape phytochemicals (HF+MGP), or HF + 0.4% muscadine wine phytochemicals (HF+MWP) for 15 weeks. At 7 weeks, mice fed HF+MGP had significantly decreased body weights by 12% compared to HF controls. Dietary MGP or MWP supplementation reduced plasma content of free fatty acids, triglycerides, and cholesterol in obese mice. Inflammation was alleviated, and activity of glutathione peroxidase was enhanced. Consumption of MGP or MWP improved insulin sensitivity and glucose control in mice. Thus, consumption of muscadine grape and wine phytochemicals in the diet may help to prevent obesity-related metabolic complications.

Pharmacokinetic Characterization and Bioavailability of Strawberry Anthocyanins Relative to Meal Intake

Plasma strawberry anthocyanins were characterized in overweight (BMI: 26 ± 2 kg/m(2)) adults (n = 14) on the basis of meal timing. At each visit, subjects ingested three study drinks: two control and one strawberry drink. A strawberry drink was given at either 2 h before the breakfast meal (BM), with the meal (WM), or 2 h after the meal (AM), and control drinks were given at the alternative time points. Plasma anthocyanins and their metabolic conjugates were assessed hourly for 10 h using a triple-quadrupole liquid chromatography mass spectrometer. Maximum concentrations (Cmax), area under the curve (AUC), and bioavailability of pelargonidin-based anthocyanins determined from the main conjugated metabolite (pelargonidin glucuronide) were greater when a strawberry drink was consumed 2 h before the meal (BM) compared to consumption WM or AM (p < 0.05). Our results indicate that the timing of strawberry consumption relative to a meal impacts anthocyanin pharmacokinetic variables.

Effects of exogenous abscisic acid on fruit quality, antioxidant capacities, and phytochemical contents of southern high bush blueberries

Abscisic acid (ABA) is a plant growth regulator that has a potential to increase antioxidant capacity and phenolic content of fruits and vegetables. The objective of this study was to examine whether an exogenous ABA application can positively affect fruit quality, antioxidant capacity, and phytochemical content of southern high bush blueberries (Vaccinium darrowii). Two varieties, namely Star and Windsor, were tested with ABA water solutions of three concentrations (0, 200, and 400ppm) using a randomised complete block design. Results showed that ABA significantly increased the firmness of berries in both varieties, suggesting a ripening delay effect. Such effect was more pronounced in Windsor variety as reflected by a lower percentage of ripe berries and smaller sized berries on ABA treated bushes. In conclusion, ABA delayed the ripening of blueberries, but did not affect total phenolic content, antioxidant capacity, or the content of individual phytochemicals in ripe blueberries.

Muscadine Grape (Vitis rotundifolia) or Wine Phytochemicals Reduce Intestinal Inflammation in Mice with Dextran Sulfate Sodium-Induced Colitis.

The objective of this study was to determine the anti-inflammatory effects of phytochemical extracts from muscadine grapes or wine on dextran sulfate sodium (DSS)-induced colitis in mice and to investigate cellular mechanisms. Two groups of C57BL/6J mice were gavaged with muscadine grape phytochemicals (MGP) or muscadine wine phytochemicals (MWP), respectively, for 14 days. Acute colitis was induced by 3% DSS in drinking water for 7 days. An additional two groups of mice served as healthy and disease controls. Results indicated that MGP or MWP significantly prevented weight loss, reduced disease activity index, and preserved colonic length compared to the colitis group (p ≤ 0.05). MGP or MWP significantly decreased myeloperoxidase activity as well as the levels of IL-1β, IL-6, and TNF-α in colon (p ≤ 0.05). MGP or MWP caused down-regulation of the NF-κB pathway by inhibiting the phosphorylation and degradation of IκB in a dose-dependent manner. These findings suggest that phytochemicals from muscadine grape or wine mitigate ulcerative colitis via attenuation of pro-inflammatory cytokine production and modulation of the NF-κB pathway.

Characterization of Wild Blueberry Polyphenols Bioavailability and Kinetic Profile in Plasma over 24-hour Period in Human Subjects

SCOPE Understanding the metabolic fate of polyphenols from plant foods can aid in developing dietary recommendations that maximize their health benefits. Wild blueberries (WBB) provide a distinctive composition of dietary anthocyanins and chlorogenic acid (CGA). METHODS AND RESULTS This is a single blind, randomized, two-arm crossover controlled study. Human subjects ingested a WBB beverage (25 g freeze dried WBB powder) or placebo beverage with a meal and plasma was collected over 24 h. Anthocyanins, CGA and their metabolites were characterized and quantified in beverages and in plasma using targeted and non-targeted mass analyses. Bioavailability of WBB anthocyanins and 3-CGA was 1.1 and 0.2%, respectively. Parent anthocyanins and 3-CGA peaked ≈2 h post ingestion, while phase II metabolites, including glucuronide conjugates of peonidin, delphinidin, cyanidin and petunidin peaked ≈ 2.6, 6.3, 7 and 8.8 h, respectively. Phenolic acids (metabolites) peaked between 0.5 and 24 h. Biphasic responses were evident suggesting preferential enterohepatic recycling for some compounds. CONCLUSION The data indicate bioavailability of early and late phase WBB metabolites peaking at different times during the 24 h period, which may be important for maximizing their biological activity.

Mathematical modeling of the adsorption/desorption characteristics of anthocyanins from muscadine (Vitis rotundifolia cv. Noble) juice pomace on Amberlite FPX66 resin in a fixed bed column: Adsorption/desorption characteristics of anthocyanins from muscadine juice pomace

BACKGROUND Muscadine grape pomace, a by-product of juicing and wine-making, contains significant amounts of anthocyanin 3,5-diglucosides, known to be beneficial to human health. RESULTS The objective of this research was to use mathematical modeling to investigate the adsorption/desorption characteristics of these anthocyanins from muscadine grape pomace on Amberlite FPX66 resin in a fixed bed column. Anthocyanins were extracted using hot water and ultrasound, and the extracts were loaded onto a resin column at five bed depths (5, 6, 8, 10 and 12 cm) using three flow rates (4, 6 and 8 mL min-1 ). It was found that adsorption on the column fitted the bed depth service time (BDST) model and the empty bed residence time (EBRT) model. Desorption was achieved by eluting the column using ethanol at four concentrations (25, 40, 55 and 70% v/v) and could be described with an empirical sigmoid model. The breakthrough curves of anthocyanins fitted the BDST model for all three flow rates with R2 values of 0.983, 0.992 and 0.984 respectively. The EBRT model was successfully employed to find the operating lines, which allow for column scale-up while still achieving similar results to those found in a laboratory operation. Desorption with 40% (v/v) ethanol achieved the highest recovery rate of anthocyanins at 79.6%. CONCLUSION The mathematical models established in this study can be used in designing a pilot/industrial- scale column for the separation and concentration of anthocyanins from muscadine juice pomace.

Chapter 35 – Anthocyanins

Anthocyanins are natural plant pigments imparting red, blue, and purple colors to flowers, leaves, fruits, and some vegetables. In addition to fruits and vegetables baring these colors, other sources of intake include dietary supplements and natural colorants of food and beverages. Anthocyanins have a complex metabolic fate that includes extensive presystemic metabolism giving rise to a wide range of metabolites. Anthocyanins modify the expression and activity of cellular and tissue targets influencing various systems associated with health benefits, including anticancer, vascular, metabolic, and neuronal health. Assessments of anthocyanin safety and toxicology indicate that acute toxicity is very low in animals and there are no reports indicating adverse health effects in humans with consumption of anthocyanins at usual dietary intake levels. Currently, there is no recommended intake level of anthocyanins for optimal health or to avoid adverse effects; however, future research and continued consumer interest will undoubtedly present opportunities for pursing dietary guidance recommendations.