Uptake and bioavailability of anthocyanins and phenolic acids from grape/blueberry juice and smoothie in vitro and in vivo.

The goal of eating five servings of fruits and vegetables a day has not yet been achieved. The intake of polyphenols such as anthocyanins (ACN) could be improved by consuming smoothies and juices that are increasingly popular, especially in children; however, bioavailability data concerning food matrix effects are scarce. Thus, we conducted a randomised, cross-over, bioavailability study (n 10) to determine the bioavailability of ACN and their metabolites from an ACN-rich grape/blueberry juice (841 mg ACN/litre) and smoothie (983 mg ACN/litre) in vivo, and the uptake of a corresponding grape/blueberry extract in vitro. After the intake of beverage (0·33 litres), plasma and fractionated urine samples were collected and analysed by ultra-performance liquid chromatography coupled to MS. The most abundant ACN found in plasma and urine were malvidin and peonidin as native ACN and as glucuronidated metabolites as well as 3,4-dihydroxybenzoic acid (3,4-DHB); minor ACN (delphinidin, cyanidin and petunidin) were only detected as native glycosides. Plasma pharmacokinetics and recoveries of urinary metabolites of ACN were not different for juice or smoothie intake; however, the phenolic acid 3,4-DHB was significantly better bioavailable from juice in comparison to smoothie. In vitro data with absorptive intestinal cells indicated that despite their weak chemical stability, ACN and 3,4-DHB could be detected at the basal side in their native forms. Whether smoothies as well as juices should be recommended to increase the intake of potentially health-promoting ACN and other polyphenols requires the consideration of other ingredients such as their relatively high sugar content.

Inhibition of low-grade inflammation by anthocyanins from grape extract in an in vitro epithelial-endothelial co-culture model.

BACKGROUND: Anthocyanins (ACNs) are the most prevalent flavonoids in berries and their health promoting effects on vascular functions are still discussed. The aim of the present study was to identify the anti-inflammatory effect of ACNs on activated human umbilical vein endothelial cells (HUVECs) after their transport across an epithelial monolayer. STUDY DESIGN: We established a transwell epithelial-endothelial co-culture system with Caco-2/HT29-B6 cells mimicking the intestinal layer and HUVECs as endothelial cells mimicking the vascular layer. Caco-2 were seeded alone (100%) or together with HT29-B6 cells (10 and 20%) on transwell inserts in order to simulate different metabolization sides of the gut. ACNs as well as malvidin-3-glucoside (M3G) were applied to the luminal compartment of the transwell-system. Transport and degradation rates were determined by high performance liquid chromatography with ultraviolet detection (HPLC-UV) or by ultra-PLC coupled to mass spectrometry (UPLC-MS). After 4 hours incubation time, co-cultured HUVECs were used immediately (short-term incubation) or after 20 hours (long-term incubation). Thereafter, HUVECs were stimulated for 3 hours with 1 ng mL(-1) TNF-α to mimic a low-grade or 10 ng mL(-1) to mimic a high-grade inflammation. Afterwards, (1.) leukocyte adhesion, (2.) expression of cell adhesion molecules (ICAM-1, VCAM-1 and E-selectin) and (3.) cytokine expression and secretion (IL-6 and IL-8) were determined using flow cytometry and real-time PCR. RESULTS: Degradation and incubation studies revealed that ACNs were differently degraded depending on the ACN structure and the seeding densities. Incubation of ACNs and M3G to Caco-2 cells (100%) led to a fast decrease, which was not observed when HT29-B6 cells were co-cultured (10 and 20%). Concomitantly, anti-inflammatory effects were only observed using 100% Caco-2 cells, whereas mixtures of Caco-2 and HT29-B6 cells failed to induce an effect. ACN extract and M3G significantly attenuated TNF-α-stimulated low-grade leukocyte adhesion, expression of adhesion molecules E-selectin, VCAM-1 and ICAM-1 and cytokine expression and secretion (IL-8 and IL-6) as well as NF-κB mRNA expression. No effects were observed with high TNF-α (10 ng mL(-1)) or after short-term incubation (4 hours). CONCLUSIONS: ACNs in physiological concentrations reached the serosal compartment and reduced inflammation-related parameters, which were related to the initial steps during the pathogenesis of atherosclerosis.

Anthocyanins from fruit juices improve the antioxidant status of healthy young female volunteers without affecting anti-inflammatory parameters: results from the randomised, double-blind, placebo-controlled, cross-over ANTHONIA (ANTHOcyanins in Nutrition Investigation Alliance) study.

Anthocyanins (ACN) can exert beneficial health effects not only through their antioxidative potential but also through modulation of inflammatory parameters that play a major role in CVD. A randomised cross-over study was carried out to investigate the effects of ACN-rich beverage ingestion on oxidation- and inflammation-related parameters in thirty healthy female volunteers. The participants consumed 330 ml of beverages (placebo, juice and smoothie with 8·9 (SD 0·3), 983·7 (SD 37) and 840·9 (SD 10) mg/l ACN, respectively) over 14 d. Before and after each intervention, blood and 24 h urine samples were collected. Plasma superoxide dismutase (SOD) and catalase activities increased significantly after ACN-rich beverage ingestion (P<0·001), whereas after placebo juice ingestion no increase could be observed. Plasma glutathione peroxidase and erythrocyte SOD activities were not affected. An increase in Trolox equivalent antioxidant capacity could also be observed after juice (P<0·001) and smoothie (P<0·01) ingestion. The plasma and urinary concentrations of malondialdehyde decreased after ACN-rich beverage ingestion (P<0·001), whereas those of 8-OH-2-deoxyguanosine as well as inflammation-related parameters (IL-2, -6, -8 and -10, C-reactive peptide, soluble cluster of differentiation 40 ligand, TNF-α, monocyte chemoattractant protein-1 and soluble cell adhesion molecules) were not affected. Thus, ingestion of ACN-rich beverages improves antioxidant enzyme activities and plasma antioxidant capacity, thus protecting the body against oxidative stress, a hallmark of ongoing atherosclerosis.

Anthocyanin-rich juice does not affect gut-associated immunity in Fischer rats.

SCOPE: Most studies on immunomodulatory effects of anthocyanins are concentrated on their anti-inflammatory potential. In vitro studies suggest that anthocyanins possess anti-inflammatory potential, but results from in vivo studies are rare and inconclusive. Sparse information is available about the immune tissues that are affected by anthocyanins. As systemic bioavailability of anthocyanins is rather low, predominantly luminal anthocyanins could influence the gut-associated lymphoid tissue (GALT). Therefore, the present study investigated the immunomodulatory effects of an anthocyanin-rich grape-bilberry juice (ARJ) on the systemic immune system, GALT, and mesenteric adipose tissue (MAT). METHODS AND RESULTS: Fischer rats (n = 24/group) received ARJ or anthocyanin-depleted grape-bilberry juice (control) for 10 wk. Lymphocytes were isolated from blood, spleen, Peyer's Patches, and mesenteric lymph nodes. Anthocyanin intake was 15 mg/day and concentrations were determined in plasma and intestinal tract. Number of T and natural killer cells, natural killer cell activity, cytokine secretion from lymphocytes (IL-10, IFN-γ, and TNF-α) and MAT (IL-6, IL-10, and MCP-1), inflammation markers in serum (sICAM, IFN-γ, and MCP-1), and activation status of NF-κB were not influenced by ARJ. CONCLUSION: This in vivo study suggests that anthocyanins at physiological doses affect neither the systemic immune system, nor GALT, or MAT in healthy, unchallenged rats.

Liking of anthocyanin-rich juices by children and adolescents.

There is evidence that a diet rich in plant foods is protective against cardiovascular disease and cancer, partly attributable to secondary plant metabolites such as anthocyanins, a colourful group of flavonoids. As at present children and adolescents do not consume the recommended amounts of fruits and vegetables, one possible way of increasing intake, and particularly intake of anthocyanins, may be an anthocyanin-rich juice, since fruit juice is popular with young Germans. We produced eight different fruit products (six juices, two smoothies), and conducted hedonic tests with participants from the DONALD Study. Paired comparisons showed that most subjects preferred apple to apple-bilberry juice, but grape vs. grape-bilberry juice was liked equally frequently. Rated on a hedonic scale the grape-bilberry mixture was preferred to apple-bilberry, both as juice and as smoothie. With regard to viscosity, juices were preferred to smoothies, both as grape-bilberry and as apple-bilberry. Internal Preference Mapping revealed however consumer subgroups with different preferences, raising the question which product should be promoted in order to reach a large target group. The product richest in anthocyanins, grape-bilberry juice, was accepted very well and may therefore be suitable for promotion to children, although the high sugar content of this juice must be taken into account.

Unusual sulfur chemistry in the thermal reaction of sultene and thiophene endoperoxide sulfur donors with cyclic alkynes: reversible formation of a persistent thiirenium ion and trapping of a thiirene by [4 + 2] cycloaddition.

The highly reactive cyclooctyne 2b serves as sulfur acceptor for both sulfur donors, namely the sultene 1A and thiophene endoperoxide 1B to afford sulfur-transfer products. With the acid-activated sultene 1A, the persistent thiirenium ion 3Ab is formed, which has allowed the direct observation of the initial sulfur-transfer adduct. On treatment with base, the thiirenium ion 3Ab reverts quantitatively to the cyclooctyne and sultene, whereas in neutral media it rearranges to the diene 6Ab. The rearrangement to the diene 6Ab, as well as the formation of spirocyclic adduct 6Ac in the reaction with dithiocyclononyne 2c, is proposed to proceed through a carbene mechanism. In the reaction of the cyclooctyne 2b with thiophene endoperoxide 1B, a thiirene is formed through sulfur transfer by an intermediary oxathiirane derived from the thiophene endoperoxide; as final product, the episulfide (R*,R*,R*)-3Bb is produced diastereoselectively by immediate [4 + 2] cycloaddition of the thiirene with the heterodiene 4B.

Lewis acid catalyzed sulfur transfer from a sultene to strained cyclic alkenes.

[reaction: see text] Sultene 1 reacts with cyclic alkenes under mild Lewis acid catalysis to form thiiranes diastereoselectively. With 1-methoxycyclooctene as sulfur acceptor, an unexpected insertion product is formed, which provides valuable mechanistic insight into the sulfur-transfer process.