Efficient in vitro digestion of lipids and proteins in bovine milk fat globule membrane ingredient (MFGMi) and whey-casein infant formula with added MFGMi.

The relative immaturity of the infant digestive system has the potential to affect the bioavailability of dietary lipids, proteins, and their digested products. We performed a lipidomic analysis of a commercial bovine milk fat globule membrane ingredient (MFGMi) and determined the profile of lipids and proteins in the bioaccessible fraction after in vitro digestion of both the ingredient and whey-casein-based infant formula without and with MFGMi. Test materials were digested using a static 2-phase in vitro model, with conditions simulating those in the infant gut. The extent of digestion and the bioaccessibility of various classes of neutral and polar lipids were monitored by measuring a wide targeted lipid profile using direct infusion-mass spectrometry. Digestion of abundant proteins in the ingredient and whey-casein infant formula containing the ingredient was determined by denaturing PAGE with imaging of Coomassie Brilliant Blue stained bands. Cholesterol esters, diacylglycerides, triacylglycerides, phosphatidylcholines, and phosphatidylethanolamines in MFGMi were hydrolyzed readily during in vitro digestion, which resulted in marked increases in the amounts of free fatty acids and lyso-phospholipids in the bioaccessible fraction. In contrast, sphingomyelins, ceramides, and gangliosides were largely resistant to simulated digestion. Proteins in MFGMi and the infant formulas also were hydrolyzed efficiently. The results suggest that neutral lipids, cholesterol esters, phospholipids, and proteins in MFGMi are digested efficiently during conditions that simulate the prandial lumen of the stomach and small intestine of infants. Also, supplementation of whey-casein-based infant formula with MFGMi did not appear to alter the profiles of lipids and proteins in the bioaccessible fraction after digestion.

Gastrointestinal metabolism and bioaccessibility of selected anthocyanins isolated from commonly consumed fruits.

There is uncertainty about the identity of digestive metabolites of anthocyanins because many are naturally present in foods and/or are formed from other phenolic compounds during the digestive process. Studies using pure anthocyanins are needed to clarify this uncertainty. In this study, selected anthocyanins were purified from common fruits and individually subjected to gastric and small intestinal digestion in vitro to determine their stability, metabolites generated and bioaccessibility. Anthocyanins were highly stable during the gastric phase of simulated digestion (p > 0.05). The recovery of anthocyanins decreased during the small intestinal phase of digestion (p < 0.05). Stability was dependent on anthocyanidin structure and type of glycation (p < 0.05). Gastric and gastrointestinal phases mainly contained anthocyanins as bioaccessible flavylium cations and chalcones. Expected anthocyanin metabolites (i.e., phenolic acids and phoroglucinaldehyde) were not detected in chyme. Deglycation of anthocyanins during simulated digestion was quite limited and the bioaccessibility of intact anthocyanins was very low (0.07-2.21%).

The NCI-N87 Cell Line as a Gastric Epithelial Model to Study Cellular Uptake, Trans-Epithelial Transport, and Gastric Anti-Inflammatory Properties of Anthocyanins.

Anthocyanins are ubiquitous plant pigments with reported antioxidant, anti-inflammatory, and anti-cancer activities. To better understand these benefits, metabolism of anthocyanins requires further evaluation, especially in the stomach. Mammalian cell cultures provide useful models for investigating compound metabolism and absorption, but they are generally maintained at physiological pH. The NCI-N87 cell line is an acid-stable model of the gastric epithelium used to study gastric drug metabolism. The objective of this work was to investigate the uptake, trans-epithelial transport, and anti-inflammatory activity of anthocyanins by the NCI-N87 cell line. The cells formed a coherent monolayer, stable ≤32 days post confluency. Minimal effects on monolayer integrity were observed when the pH of the apical chamber was adjusted to pH 3.0, 5.0, or 7.4. Anthocyanins were transported across the NCI-N87 cell monolayer at 37 °C, but not at 0 °C, suggesting a facilitated process. Chokeberry anthocyanins (0-1500 µM) were not cytotoxic. At apical pH 3.0, they had anti-inflammatory properties by significantly attenuating IL-8 secretion when added to medium before, during, and after incubation with IL-1ß. These results suggest that the NCI-N87 cell line is a physiologically relevant model for in vitro studies of the transport, anti-inflammatory and potential anti-carcinogenic activities of anthocyanins in gastric tissue.

Comparison of Two Static in Vitro Digestion Methods for Screening the Bioaccessibility of Carotenoids in Fruits, Vegetables, and Animal Products.

In vitro digestion methods are routinely used to assess the bioaccessibility of carotenoids and other dietary lipophilic compounds. Here, we compared the recovery of carotenoids and their efficiency of micellarization in digested fruits, vegetables, egg yolk, and salmon and also in mixed-vegetable salads with and without either egg yolk or salmon using the static INFOGEST method22 and the procedure of Failla et al.16 Carotenoid stability during the simulated digestion was ≥70%. The efficiencies of the partitioning of carotenoids into mixed micelles were similar when individual plant foods and salad meals were digested using the two static methods. Furthermore, the addition of cooked egg or salmon to vegetable salads increased the bioaccessibility of some carotenoids. Our findings showed that the two methods of in vitro digestion generated similar estimates of carotenoid retention and bioaccessibility for diverse foods.

Potential of golden potatoes to improve vitamin A and vitamin E status in developing countries.

Potato (Solanum tuberosum L.) is the third most widely consumed plant food by humans. Its tubers are rich in starch and vitamin C, but have low or null levels of essential nutrients such as provitamin A and vitamin E. Transformation of potato with a bacterial mini-pathway for ß-carotene in a tuber-specific manner results in a "golden" potato (GP) tuber phenotype resulting from accumulation of provitamin A carotenoids (α- and ß-carotene) and xanthophylls. Here, we investigated the bioaccessibility of carotenoids and vitamin E as α-tocopherol (αTC) in boiled wild type and golden tubers using in vitro digestion. Golden tubers contained up to 91 µg provitamin A carotenes (PAC)/g D, increased levels of xanthophylls, phytoene and phytofluene, as well as up to 78 µg vitamin E/g DW. Cubes from wild type and GP tubers were boiled and subjected to simulated digestion to estimate bioaccessibility of carotenoids and αTC. Retention in boiled GPs exceeded 80% for ß-carotene (ßC), α-carotene (αC), lutein, phytoene ± and αTC, but less than 50% for phytofluene. The efficiency of partitioning of total ßC, αC, E-lutein, phytoene, phytofluene and αTC in the mixed micelle fraction during small intestinal digestion was influenced by genotype, tuber content and hydrophobicity. Apical uptake of the compounds that partitioned in mixed micelles by monolayers of human intestinal Caco-2 cells during incubation for 4h was 14-20% for provitamin A and xanthophylls, 43-45% for phytoene, 23-27% for phytofluene, and 53% for αTC. These results suggest that a 150 g serving of boiled golden potatoes has the potential to contribute 42% and 23% of the daily requirement of retinol activity equivalents (RAE), as well as 34 and 17% of the daily vitamin E requirement for children and women of reproductive age, respectively.

Bioaccessibility and intestinal cell uptake of astaxanthin from salmon and commercial supplements.

Although the keto-carotenoid astaxanthin (Ast) is not typically present in human plasma due to its relative scarcity in the typical diet, global consumption of salmon, the primary source of Ast in food, and Ast supplements continues to increase. The first objective of the present study was to investigate the bioaccessibility of Ast from uncooked and cooked fillets of wild and aquacultured salmon, Ast-supplements and krill oil, during simulated gastric and small intestinal digestion. Uptake of E-Ast from micelles generated during digestion of wild salmon by monolayers of Caco-2 was also monitored. Both wild and aquacultured salmon flesh contained E-Ast and Z-isomers of unesterified Ast, whereas Ast esters were the predominant form of the carotenoid in commercial supplements and krill oil. Flesh from wild salmon contained approximately 10 times more Ast than aquacultured salmon. Common styles of cooking flesh from wild and aquacultured salmon decreased Ast content by 48-57% and 35-47%, respectively. Ast in salmon flesh, supplements and krill oil was relatively stable (>80% recovery) during in vitro digestion. The efficiency of transfer of Ast into mixed micelles during digestion of uncooked wild salmon was 43%, but only 12% for uncooked acquacultured salmon. Cooking wild salmon significantly decreased Ast bioaccessibility. The relative bioaccessibility of Ast (41-67%) after digestion of oil vehicle in commercial supplements was inversely proportional to carotenoid content (3-10mg/capsule), whereas bioaccessibility of endogenous Ast in phospholipid-rich krill oil supplement was 68%. >95% of Ast in mixed micelles generated during digestion of supplements and krill oil was unesterified. Caco-2 intestinal cells accumulated 11-14% of E-Ast delivered in mixed micelles generated from digested wild salmon. Apical uptake and basolateral secretion of E-Ast by Caco-2 cells grown on inserts were greater after digestion of Ast-enriched krill oil compared to uncooked wild salmon. These data suggest that the bioacessibility of Ast in wild salmon and soft-gel capsules is greater than that in aquacultured salmon, and that uptake and basolateral secretion of the carotenoid by enterocyte-like cells is enhanced by the digestion products of phospholipid-rich krill oil.

α-Tocopherol bioavailability is lower in adults with metabolic syndrome regardless of dairy fat co-ingestion: a randomized, double-blind, crossover trial.

BACKGROUND: Increasing dietary fat intake is expected to improve α-tocopherol bioavailability, which could be beneficial for improving α-tocopherol status, especially in cohorts at high cardiometabolic risk who fail to meet dietary α-tocopherol requirements. OBJECTIVE: Our objective was to assess dose-dependent effects of dairy fat and metabolic syndrome (MetS) health status on α-tocopherol pharmacokinetics in plasma and lipoproteins. DESIGN: A randomized, crossover, double-blind study was conducted in healthy and MetS adults (n = 10/group) who ingested encapsulated hexadeuterium-labeled (d6)-RRR-α-tocopherol (15 mg) with 240 mL nonfat (0.2 g fat), reduced-fat (4.8 g fat), or whole (7.9 g fat) milk before blood collection at regular intervals for 72 h. RESULTS: Compared with healthy participants, those with MetS had lower (P < 0.05) baseline plasma α-tocopherol (µmol/mmol lipid) and greater oxidized low-density lipoprotein (LDL), interleukin (IL)-6, IL-10, and C-reactive protein. Regardless of health status, d6-α-tocopherol bioavailability was unaffected by increasing amounts of dairy fat provided by milk beverages, but MetS participants had lower estimated d6-α-tocopherol absorption (±SEM) than did healthy participants (26.1% ± 1.0% compared with 29.5% ± 1.1%). They also had lower plasma d6-α-tocopherol AUC from 0 to 72 h, as well as maximal concentrations (Cmax: 2.04 ± 0.14 compared with 2.73 ± 0.18 µmol/L) and slower rates of plasma disappearance but similar times to Cmax. MetS participants had lower d6-α-tocopherol AUC from t = 0-12 h (AUC0- t final) in lipoprotein fractions [chylomicron, very-low-density lipoprotein (VLDL), LDL, high-density lipoprotein]. Percentages of d6-α-tocopherol AUC0- t final in both the chylomicron (r = -0.46 to -0.52) and VLDL (r = -0.49 to -0.68) fractions were inversely correlated with oxidized LDL, IL-10, IL-6, and C-reactive protein. CONCLUSIONS: At dietary intakes equivalent to the Recommended Dietary Allowance, α-tocopherol bioavailability is unaffected by dairy fat quantity but is lower in MetS adults, potentially because of greater inflammation and oxidative stress that limits small intestinal α-tocopherol absorption and/or impairs hepatic α-tocopherol trafficking. These findings support higher dietary α-tocopherol requirements for MetS adults. This trial was registered at www.clinicaltrials.gov as NCT01787591.

The effect of ripening, heat processing and frozen storage on the in vitro bioaccessibility of capsaicin and dihydrocapsaicin from Jalapeño peppers in absence and presence of two dietary fat types.

To date, there is no information in the literature regarding the bioaccessibility of capsaicinoids from natural sources. The effect of ripening and heat-processing on the in vitro bioaccessibility of capsaicin and dihydrocapsaicin was studied in the absence and presence of two dietary fat types. The capsaicinoid bioaccessibility was also studied during the frozen storage of peppers for 6 months. Fresh green peppers showed the highest capsaicinoid bioaccessibility, as compared with that of other experimental groups. The bioaccessibility of capsaicinoids from green peppers decreased as the intensity of heat treatment increased. The dietary fat increased the bioaccessibility of capsaicin and dihydrocapsaicin in digestions with red peppers, especially that of dihydrocapsaicin. The bioaccessibility of capsaicinoids was altered by frozen storage. The Caco-2 cells incorporated capsaicin and dihydrocapsaicin (8.4% and 10.9%, respectively) but they were probably metabolized by cells.

Comparison of content and in vitro bioaccessibility of provitamin A carotenoids in home cooked and commercially processed orange fleshed sweet potato (Ipomea batatas Lam).

Vitamin A deficiency (VAD) remains a public health problem in some regions of Brazil. Increased use of orange-fleshed sweet potato (OFSP) as a source of pro-vitamin A represents a potential strategy for prevention of VAD. We compared the pro-vitamin A content, vitamin A equivalency and bioaccessibility of ß-carotene (ßC) of two varieties of home cooked OFSP and two commercial sources of processed OFSP. Pro-vitamin A carotenoid content in home cooked, Beauregard variety of OFSP exceeded that in Amelia variety and commercial products for babies. All-trans-ßC was the most abundant carotenoid in raw, cooked and commercial OFSP. Boiling and frying OFSP generally decreased total ßC. A serving of 100 g FW Beauregard variety of cooked OFSP contained greater than 100% of the estimated average requirement (EAR) for children and women, and up to 92% EAR for lactating women. Although the efficiency of micellarization of all-trans-ßC during simulated digestion of OFSP was relatively low (4-8%) and significantly less than for cis-isomers, the quantities of trans-ßC incorporated into micelles from boiled Beauregard and fried Amelia varieties exceeded that in micelles generated by digesting commercial OFSP. The bioaccessibility of pro-vitamin A carotenoids in the micelle fraction of digested OFSP was confirmed with differentiated cultures of Caco-2 human intestinal cells. Continued development of OFSP such as the Amelia and Beauregard varieties that are rich in trans-ßC and dissemination of best practices for home cooking are encouraged to increase consumption of this food to decrease the risk of vitamin A deficiency in Brazil.

Intestinal microbial dysbiosis and colonic epithelial cell hyperproliferation by dietary α-mangostin is independent of mouse strain.

Beverages and supplements prepared from mangosteen fruit are claimed to support gut health and immunity, despite the absence of supporting evidence from clinical trials. We recently reported that α-mangostin (α-MG), the most abundant xanthone in mangosteen fruit, altered the intestinal microbiome, promoted dysbiosis, and exacerbated colitis in C57BL/6J mice. The objective of this study was to determine whether induction of dysbiosis by dietary α-MG is limited to the C57BL/6J strain or represents a more generic response to chronic intake of the xanthone on the gut microbiota of mice. C3H, Balb/c, Nude FoxN1nu, and C57BL/6J mice, each demonstrating unique microbiomes, were fed standard diet or diet containing 0.1% α-MG for four weeks. Dietary α-MG significantly altered the cecal and colonic microbiota in all four strains of mice, promoting a reduction in generally assumed beneficial bacterial groups while increasing the abundance of pathogenic bacteria. Consumption of α-MG was associated with reduced abundance of Firmicutes and increased abundance of Proteobacteria. The abundance of Lachnospiraceae, Ruminococcaceae, and Lactobacillaceae was reduced in α-MG-fed mice, while that of Enterobacteriaceae and Enterococcaceae was increased. Dietary α-MG also was associated with increased proliferation of colonic epithelial cells, infiltration of immune cells, infiltration of immune cells and increased fluid content in stool. These results suggest that ingestion of pharmacologic doses of xanthones in mangosteen-containing supplements may adversely alter the gut microbiota and should be used with caution.

Increased bioavailability of ubiquinol compared to that of ubiquinone is due to more efficient micellarization during digestion and greater GSH-dependent uptake and basolateral secretion by Caco-2 cells.

The oral bioavailability of ubiquinol recently has been reported to be greater than that of ubiquinone in healthy adults. The basis for this influence of redox state of coenzyme Q (CoQ) on bioavailability has been investigated using the coupled in vitro digestion/Caco-2 cell model. Solubilized ubiquinol and ubiquinone were added to yogurt and subjected to simulated gastric and small intestinal digestion. Partitioning of CoQ in mixed micelles during small intestinal digestion was significantly greater during digestion of yogurt enriched with ubiquinol. Similarly, apical uptake from mixed micelles and transepithelial transport of CoQ by Caco-2 cells were significantly greater after digestion of the ubiquinol-rich yogurt compared to digested ubiquinone-rich yogurt. Reduction of cellular GSH significantly decreased cell uptake and basolateral secretion of both ubiquinol and ubiquinone, although the adverse impact was much greater for ubiquinol. These data suggest that the enhanced bioaccessibility and bioavailability of ubiquinol compared to ubiquinone results from reduced coenzyme being more efficiently incorporated into mixed micelles during digestion and its greater uptake and basolateral secretion in a glutathione-dependent mechanism.

Impact of genotype and cooking style on the content, retention, and bioacessibility of ß-carotene in biofortified cassava (Manihot esculenta Crantz) conventionally bred in Brazil.

Biofortification is a strategy for decreasing micronutrient deficiencies in vulnerable populations by increasing nutrient density in staple food crops. Roots from five varieties of cassava biofortified with ß-carotene (ßC), three parental accessions, and one variety of commonly consumed white cassava from Brazil were investigated. Roots from biofortified varieties contained up to 23-fold higher ßC than white cassava, and the additional complement of ßC was primarily the all-trans isomer. At least 68% of ßC per gram fresh weight was retained after boiling or boiling and briefly frying. Micellarization of ßC during simulated digestion of fried root exceeded that of boiled root. Apical uptake of all-trans-ßC from mixed micelles by Caco-2 cells was affected by an interaction between variety and cooking style. These results suggest that Brazilian cassava biofortified with ßC has the potential to reduce vitamin A deficiency without requiring major changes in local and ethnic styles of home cooking.

Unsaturated fatty acids promote bioaccessibility and basolateral secretion of carotenoids and α-tocopherol by Caco-2 cells.

Bioavailability of carotenoids and tocopherols from foods is determined by the efficiency of transfer from food/meal to mixed micelles during digestion, incorporation into chylomicrons for trans-epithelial transport to lymphatic/blood system, and distribution to target tissues. Fats and oils are important factors for facilitating the absorption of lipophilic compounds. However, dietary fats and oils are composed of various types of saturated and unsaturated fatty acids which may differentially impact the bioavailability of carotenoids and tocopherols from foods. We have investigated the effects of several common commercial lipids on bioavailability using an in vitro digestion model and Caco-2 human intestinal cells. Meals consisted of mixed salad vegetables containing a single test lipid. Micellarization and cellular uptake of ß-carotene (ßC) and lycopene (LYC) during small intestinal digestion was increased by lipids rich in unsaturated fatty acids: soybean oil > olive > canola > butter. In contrast, type of lipid minimally affected the bioaccessibility of lutein (LUT) and zeaxanthin (ZEA). To examine the influence of type of dietary triglyceride on uptake and basolateral secretion of carotenoids, Caco-2 cells grown on Transwell membranes were incubated with micellar mixtures of fatty acids (1.0 mM) mimicking the types and ratio of saturated to unsaturated (mono- + poly-unsaturated) fatty acids (FA) present in butter (70 : 30), olive oil (7 : 93) and soybean oil (11 : 89). Cells were exposed to micelles containing ßC, LUT, α-tocopherol (α-TC) and a mixture of test fatty acids. Uptake and basolateral secretion of ßC, LUT and α-TC were greater in cells pre-treated with mixtures enriched in unsaturated compared to saturated FA and these effects were mediated by increased assembly and secretion of chylomicrons. These results suggest that dietary fats/oils rich in unsaturated fatty acids promote carotenoid and α-TC bioavailability by enhancing their micellarization during digestion and intestinal transport.

Anthocyanin structure determines susceptibility to microbial degradation and bioavailability to the buccal mucosa.

Anthocyanins are flavonoids with reported chemoprotective activities in the oral cavity. However, information about their stability, metabolism, and tissue uptake in the mouth is limited. Anthocyanin chemical structure was recently shown to affect their stability ex vivo in saliva, and it was hypothesized that structure may affect their availability in oral tissues in vivo. Here, 12 healthy individuals retained red grape or chokeberry juice in the mouth for 5 min. Anthocyanin stability, mucus binding, and uptake into epithelial cells were evaluated. Loss of delphinidin-3-glucoside in red grape juice exceeded that of other anthocyanin-glucosides, and lesser amounts of delphinidin- and petunidin-glucosides were associated with buccal scraping, suggesting the loss was due to degradation. In chokeberry juice, loss of cyanidin-3-xyloside exceeded that of other anthocyanins, whereas cyanidin-3-glucoside preferentially accumulated in epithelium cells. These results suggest that anthocyanin structure affects stability and buccal cell uptake and therefore the potential efficacy of anthocyanin-rich products for the promotion of oral health.

Dietary α-mangostin, a xanthone from mangosteen fruit, exacerbates experimental colitis and promotes dysbiosis in mice.

SCOPE: Ulcerative colitis (UC) is a chronic inflammatory disease of the colon. α-Mangostin (α-MG), the most abundant xanthone in mangosteen fruit, exerts anti-inflammatory and antibacterial activities in vitro. We evaluated the impact of dietary α-MG on murine experimental colitis and on the gut microbiota of healthy mice. METHODS AND RESULTS: Colitis was induced in C57BL/6J mice by administration of dextran sulfate sodium (DSS). Mice were fed control diet or diet with α-MG (0.1%). α-MG exacerbated the pathology of DSS-induced colitis. Mice fed diet with α-MG had greater colonic inflammation and injury, as well as greater infiltration of CD3(+) and F4/80(+) cells, and colonic myeloperoxidase, than controls. Serum levels of granulocyte colony-stimulating factor, IL-6, and serum amyloid A were also greater in α-MG-fed animals than in controls. The colonic and cecal microbiota of healthy mice fed α-MG but no DSS shifted to an increased abundance of Proteobacteria and decreased abundance of Firmicutes and Bacteroidetes, a profile similar to that found in human UC. CONCLUSION: α-MG exacerbated colonic pathology during DSS-induced colitis. These effects may be associated with an induction of intestinal dysbiosis by α-MG. Our results suggest that the use of α-MG-containing supplements by patients with UC may have unintentional risk.

Adipocyte reporter assays: application for identification of anti-inflammatory and antioxidant properties of mangosteen xanthones.

SCOPE: Three fluorescence biosensors were developed based on a 3T3-L1 preadipocyte line that stably expressed Nfkb-RE/GFP, Fabp4-P/CFP, and Nrf2-P/YFP fluorescent reporters. We hypothesized that nutraceuticals' inflammatory, adipogenic, and antioxidant status will be identified based on the change in fluorescence in reporter adipocytes. We validated these assays with activators of NFκB, FABP4-regulating peroxisome proliferator activated receptor gamma, NFR2 and, thereafter, tested known and unknown properties of mangostines (MGs), the xanthone metabolites in mangosteen fruit. METHODS AND RESULTS: We validated inflammatory and adipogenic properties of α-MG using an Nfkb-RE/GFP biosensor assay. Next, we identified unique properties of γ-MG, a minor MG xanthone. γ-MG suppressed adipogenesis and expression of adiponectin, but inhibited the Nfkb-RE/GFP reporter and secretion of inflammatory monocyte chemotactic protein 1 as compared to the control adipocytes. We found that the inhibition of adipogenesis and Nfkb-mediated inflammation depends on a dose-dependent reduction of Nrf2 promoter activity by α-MG. The Nrf2 inhibition resulted in the reduced Pparg expression. α-MG did not directly influence Pparg activity in Fabp4-P/CFP adipocytes. CONCLUSION: α-MG-mediated antioxidant response via Nrf2 is a mechanism preventing adipogenesis and inflammation in adipocytes. Combined application of high-throughput biosensors could provide an effective platform for the identification of nutraceuticals and the mechanism of their actions in adipocytes and, potentially, in obese patients.

Biological activities and bioavailability of mangosteen xanthones: a critical review of the current evidence.

Mangosteen (Garcinia mangostana L.) is a tropical tree native to Southeast Asia that produces a fruit whose pericarp contains a family of tricyclic isoprenylated polyphenols referred to as xanthones. Numerous in vitro studies have shown that these xanthones possess anti-oxidant, anti-proliferative, pro-apoptotic, anti-inflammatory and anti-carcinogenic activities. Aggressive marketing of such health promoting benefits has resulted in mangosteen's classification as a "superfruit". This has led to sales of mangosteen containing beverages in USA alone exceeding $200 million in 2008 despite very limited animal and human studies. This review will (a) critically address recent reports of in vivo studies on the bioavailability and metabolism of mangosteen xanthones, (b) update the in vitro and in vivo data on anti-cancer and anti-inflammatory activities of mangosteen xanthones, and (c) suggest needed areas of inquiry regarding the absorption, metabolism and efficacy of mangosteen xanthones.

Saponins from soy and chickpea: stability during beadmaking and in vitro bioaccessibility.

This study investigated the stability of saponins during the making and simulated digestion of soy and soy-chickpea breads and the bioaccessibility of saponins in digested breads. Recovery of saponins in soy bread exceeded that in soy-chickpea breads, and recovery of type A and B saponins was greater than for type E and DDMP saponins. Simulated digestion of breads resulted in greater relative losses of type A and DDMP saponins than type B and E saponins due in part to conversion of DDMP. Bioaccessibility of type B, E, and DDMP saponins in aqueous fraction of chyme exceeded 50%, but was ∼30% for type A saponins. Caco-2 cells accumulated 0.8-2.8% of saponins from apical compartment containing diluted aqueous fraction of chyme. These findings suggest that saponin structure and food matrix affect the stability of saponins during processing and digestion and that uptake of saponins by enterocyte-like cells is poor despite moderate apparent bioaccessibility.

Zinc deficiency augments leptin production and exacerbates macrophage infiltration into adipose tissue in mice fed a high-fat diet.

Zinc (Zn) deficiency and obesity are global public health problems. Zn deficiency is associated with obesity and comorbid conditions that include insulin resistance and type 2 diabetes. However, the function of Zn in obesity remains unclear. Using a mouse model of combined high-fat and low-Zn intake (0.5-1.5 mg/kg), we investigated whether Zn deficiency exacerbates the extent of adiposity as well as perturbations in metabolic and immune function. C57BL/6 mice were randomly assigned to receive either a high-fat diet (HFD) or a control (C) diet for 6 wk, followed by further subdivision into 2 additional groups fed Zn-deficient diets (C-Zn, HFD-Zn), along with a C diet and an HFD, for 3 wk (n = 8-9 mice/group). The extent of visceral fat, insulin resistance, or systemic inflammation was unaffected by Zn deficiency. Strikingly, Zn deficiency significantly augmented circulating leptin concentrations (HFD-Zn vs. HFD: 3.15 ± 0.16 vs. 2.59 ± 0.12 µg/L, respectively) and leptin signaling in the liver of obese mice. Furthermore, gene expression of macrophage-specific markers ADAM8 (A disintegrin and metalloproteinase domain-containing protein 8) and CD68 (cluster of differentiation 68) was significantly greater in adipose tissue in the HFD-Zn group than in the HFD group, as confirmed by CD68 protein analysis, indicative of increased macrophage infiltration. Inspection of Zn content and mRNA profiles of all Zn transporters in the adipose tissue revealed alterations of Zn metabolism to obesity and Zn deficiency. Our results demonstrate that Zn deficiency increases leptin production and exacerbates macrophage infiltration into adipose tissue in obese mice, indicating the importance of Zn in metabolic and immune dysregulation in obesity.

Carotenoid bioavailability from raw vegetables and a moderate amount of oil in human subjects is greatest when the majority of daily vegetables are consumed at one meal.

While the impact of food composition and processing on carotenoid bioavailability has been the subject of several investigations, the effect of meal patterning remains unknown. The aim of this pilot study was to assess the impact of select consumption patterns on the bioavailability of carotenoids from vegetables. On three randomized testing days, subjects consumed raw salad vegetables and 8 g canola oil over a two meal period in three meal patterns. Meal patterns included consumption of 100% of vegetables and oil in the first meal and 0% in the second, 75% in the first meal and 25% in the second, and 50% in the first meal and 50% in the second. Additional protein-rich "chef's salad" ingredients were distributed equally between meals. We hypothesized that carotenoid absorption would be highest when 50% of vegetables and oil were consumed at each meal and lowest when 100% were consumed at once. Blood was collected 0 to 12 hours postprandially and triacylglycerol-rich lipoprotein fractions (TRL) were isolated by ultracentrifugation. TRL carotenoid concentrations were analyzed by high performance liquid chromatography-diode array detector. Considering all carotenoids, absorption expressed as area under the curve was greatest when ≥75% of vegetables were consumed in a single meal (P < .05). Absorption of carotenes also followed this trend (P < .05 for α- and ß-carotene). For xanthophylls, consuming all vegetables in one meal increased absorption compared to intake of 50% at each meal (P < .05). These data suggest that carotenoid absorption may be the greatest when daily recommended vegetables are consumed in one meal compared to smaller doses over multiple meals.