The enzymatic synthesis of EPA-rich medium- and long-chain triacylglycerol improves the digestion behavior of MCFA and EPA: evidence on in vitro digestion.

Medium-chain triglyceride (MCT) and eicosapentaenoic acid (EPA) have been widely applied in nutritional supplementation. However, when administered individually or mixed, they were unable to maximize their nutritional value. Hence, EPA-rich medium- and long-chain triacylglycerol (MLCT) was synthesized from MCT and EPA-rich fish oil (FO) by enzymatic transesterification. The fatty acids in triglyceride (TAG) were rearranged which resulted in significant changes in TAG profiles compared to the physical mixture of MCT and FO (PM). EPA-containing MML (MML, MLM and LMM) and LLM (LLM, LML and MLL) type TAGs account for 70.21%. The fate of different oils (MCT, FO, PM, and MLCT) across the gastrointestinal tract was subsequently simulated using an in vitro digestion model. The results showed that the physical and structural characteristics of different oils during digestion depended upon the oil type and the microenvironment they were in. After 120 min of small intestine digestion, the degree of hydrolysis for MLCT was higher than that for the other three oils. The final FFA release level was in the following order: MLCT (102.79%) > MCT (95.20%) > PM (85.81%) > FO (74.18%). This can be attributed to the composition and positional distribution of fatty acids in TAGs. What's more, LCFAs (EPA) in MLCT mainly existed in the form of sn-2 MAG, which was conducive to their subsequent absorption and transport. These results may aid in the future rational design of structural lipids, thereby regulating lipid digestion and maximizing the nutritional value of oils.

SULTR3s Function in Chloroplast Sulfate Uptake and Affect ABA Biosynthesis and the Stress Response.

Plants are major sulfur reducers in the global sulfur cycle. Sulfate, the major natural sulfur source in soil, is absorbed by plant roots and transported into plastids, where it is reduced and assimilated into Cys for further metabolic processes. Despite its importance, how sulfate is transported into plastids is poorly understood. We previously demonstrated using single Arabidopsis (Arabidopsis thaliana) genetic mutants that each member of the sulfate transporter (SULTR) subfamily 3 was able to transport sulfate across the chloroplast envelope membrane. To resolve the function of SULTR3s, we constructed a sultr3 quintuple mutant completely knocking out all five members of the subfamily. Here we report that all members of the SULTR3 subfamily show chloroplast membrane localization. Sulfate uptake by chloroplasts of the quintuple mutant is reduced by more than 50% compared with the wild type. Consequently, Cys and abscisic acid (ABA) content are reduced to ∼67 and ∼20% of the wild-type level, respectively, and strong positive correlations are found among sulfate, Cys, and ABA content. The sultr3 quintuple mutant shows obvious growth retardation with smaller rosettes and shorter roots. Seed germination of the sultr3 quintuple mutant is hypersensitive to exogenous ABA and salt stress, but is rescued by sulfide supplementation. Furthermore, sulfate-induced stomatal closure is abolished in the quintuple mutant, strongly suggesting that chloroplast sulfate is required for stomatal closure. Our genetic analyses unequivocally demonstrate that sulfate transporter subfamily 3 is responsible for more than half of the chloroplast sulfate uptake and influences downstream sulfate assimilation and ABA biosynthesis.

Attenuation of allergic responses following treatment with resveratrol in anaphylactic models and IgE-mediated mast cells.

Resveratrol exists widely in plant species and has a variety of anti-oxidant, anti-inflammatory, and immunomodulatory properties. However, there have been few reports regarding its anti-food allergic activity. In this study, we demonstrated that resveratrol (isolated from Abies georgei) could decrease the release of ß-hexosaminidase and histamine in rat basophilic leukemia-2H3 cells. Resveratrol was not only found to suppress the development of diarrhea, up-regulate the rectal temperature of ovalbumin-allergic mice, and decrease the serum level of specific immunoglobulin E, mouse mast cell protease-1 and histamine, but also found to decrease the population of dendritic cells, B cells and mast cells of ovalbumin -allergic mice in the spleen or mesenteric lymph node. Furthermore, resveratrol inhibited the release of ß-hexosaminidase and histamine in bone marrow-derived cells and alleviated mast cell-mediated passive cutaneous anaphylaxis reactions. These findings indicated that resveratrol isolated from Abies georgei might have the potential to alleviate food hypersensitivity or allergic disease.

Blueberry Polyphenols Ameliorate Visible Light and Lipid-Induced Injury of Retinal Pigment Epithelial Cells.

Although dietary polyphenols are known to be beneficial to vision, the protective distinctions among different types of polyphenols are unclear. In this work, the visual benefits of various blueberry polyphenols were evaluated using an in vitro model of visible light-lipid-induced injury of retinal pigment epithelial cells. Results showed that, at 10.0 µg/mL, the phenolic acid-rich fraction was superior in inhibiting cell death (93.6% ± 2.8% of cell viability). Anthocyanin- and flavonoid-rich fractions shared similar advantages in preventing the expression of senescence-associated ß-galactosidase (34.8% ± 11.1% and 32.2% ± 9.7% of aged cells, respectively) and overexpression of vascular endothelial growth factor (51.8 ± 3.5 and 54.1 ± 6.5 pg/mL, respectively). The flavonoid-rich fraction also showed high activity in ameliorating phagocytosis (70.3% ± 12.6%) and cellular oxidative stress. These results were further confirmed by using the corresponding polyphenol standards. Improved inhibitory effects of polyphenol mixture on cell death and senescence-associated ß-galactosidase expression were also observed. Therefore, various polyphenols play diverse roles and exert synergistic effects in nourishing the retina.

Potential Retinal Benefits of Dietary Polyphenols Based on Their Permeability across the Blood-Retinal Barrier.

Whether all dietary polyphenols nourish the eyes via oral supplementation is controversial. Given that passage of dietary polyphenols across the blood-retina barrier (BRB) is the precondition for polyphenols to exhibit ocular benefits, the BRB permeability of polyphenols was assessed in this study. Being common dietary polyphenols in fruits and vegetables, nonanthocyanin flavonoids, anthocyanins, and phenolic acids were investigated. BRB was simulated in vitro by using a differentiated retinal pigment epithelial cell monolayer cultivated on a Transwell culture system. Penetration rate was calculated by quantitatively analyzing the polyphenols in basolateral media. The BRB permeability of different polyphenols obviously (p < 0.05) differed, as follows: phenolic acids > nonanthocyanin flavonoids > anthocyanins. Glycosylation and methylation improved the BRB permeability of nonanthocyanin flavonoids and anthocyanins. However, instability and carbonylation at the C-4 position severely suppressed the BRB permeability of anthocyanins and nonanthocyanin flavonoids. Moreover, a new metabolite was discovered during penetration of anthocyanins into the BRB. However, hydrophilic phenolic acids exhibited better BRB permeability than hydrophobic ones. Data demonstrate that BRB permeability of polyphenols was determined based on structural characteristics, hydrophilicity, stability, and metabolic changes.

Eucheuma cottonii Sulfated Oligosaccharides Decrease Food Allergic Responses in Animal Models by Up-regulating Regulatory T (Treg) Cells.

In the present study, the anti-food allergy activity of Eucheuma cottonii sulfated oligosaccharide (ESO) was investigated. ESO was obtained by enzymatic degradation and purified by column chromatography. RBL-2H3 cells and BALB/c mouse model were used to test the anti-food allergy activity of ESO. The effects of ESO on the regulatory T (Treg) cells and bone marrow-derived mast cells (BMMCs) were investigated by flow cytometry. The results of in vivo assay showed that ESO decreased the levels of mast cell protease-1 and histamine and inhibited the levels of specific IgE by 77.7%. In addition, the production of interleukin (IL)-4 and IL-13 was diminished in the ESO groups compared to the non-ESO-treated group. Furthermore, ESO could up-regulate Treg cells by 22.2-97.1%. In conclusion, ESO decreased the allergy response in mice by reducing basophil degranulation, up-regulating Treg cells via Forkhead box protein 3 (Foxp3), and releasing IL-10. ESO may have preventive and therapeutic potential in allergic disease.

Anti-Food Allergic Activity of Sulfated Polysaccharide from Gracilaria lemaneiformis is Dependent on Immunosuppression and Inhibition of p38 MAPK.

Polysaccharides from Gracilaria lemaneiformis in particular possess various bioactive functions, but their antiallergic activity remains incompletely defined. Sulfated polysaccharide from Gracilaria lemaneiformis (GLSP) was obtained by water extraction and ethanol precipitation followed by column chromatography. BALB/c mice, RBL-2H3, and KU812 cells were used for verifying the anti food allergic activity of GLSP. According to the results of mice experiment, GLSP was able to alleviate allergy symptoms, to reduce TM-specific IgE and IgG1, to suppress Th2 cell polarization, and to promote the function of regulatory T (Treg) cells. In addition, GLSP had the ability to inhibit the function of RBL-2H3 cells. Furthermore, GLSP inhibited the activation of KU812 via suppression of p38 mitogen-activated protein kinase (MAPK). In conclusion, immunosuppression as well as the reduction in the level of p38 MAPK may contribute to GLSP's putative activity against food allergy. GLSP may be used as a functional food component for allergic patients.

Mung bean trypsin inhibitor is effective in suppressing the degradation of myofibrillar proteins in the skeletal muscle of blue scad (Decapterus maruadsi).

Mung bean trypsin inhibitor (MBTI) of the Bowman-Birk family was purified to homogeneity with a molecular mass of approximately 9 kDa on tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and 8887.25 Da as determined by matrix-assisted laser desorption/ionization-quadrupole ion trap-time-of-flight mass spectrometry (MALDI-QIT-TOF MS). Using blue scad myofibrillar proteins as targets, it was found that, in the absence of MBTI, proteolysis of myofibrillar proteins, especially myosin heavy chain (MHC), could be identified after incubation at 55 °C for 2 h, while in the presence of MBTI, with a final concentration of 25 ng/mL, proteolysis of these proteins was greatly suppressed even after incubation for 3 h. Although cysteine proteinase inhibitor E-64 was also effective in preventing protein degradation, inhibitors for metallo- and asparatic proteinases did not reveal obvious inhibitory effects. Our present results strongly suggested that the naturally occurring legume bean seed protein MBTI can be used as an effective additive in preventing marine fish blue scad surimi gel softening, which is quite possibly caused by myofibril-bound serine proteinase (MBSP).