The marine carotenoid fucoxanthin can be found in marine brown seaweeds, the macroalgae, and diatoms, the microalgae, and has remarkable biological properties. Numerous studies have shown that fucoxanthin has considerable potential and promising applications in human health. In this article, we review the current available scientific literature regarding the metabolism, safety, and bioactivities of fucoxanthin, including its antioxidant, anti-inflammatory, anticancer, anti-obese, antidiabetic, antiangiogenic and antimalarial activities, and its protective effects on the liver, blood vessels of the brain, bones, skin, and eyes. Although some studies have shown the bioavailability of fucoxanthin in brown seaweeds to be low in humans, many studies have suggested that a dietary combination of fucoxanthin and edible oil or lipid could increase the absorption rate of fucoxanthin, and thus it might be a promising marine drug.
The ketocarotenoid astaxanthin can be found in the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp., and the red yeast Phaffia rhodozyma. The microalga H. pluvialis has the highest capacity to accumulate astaxanthin up to 4-5% of cell dry weight. Astaxanthin has been attributed with extraordinary potential for protecting the organism against a wide range of diseases, and has considerable potential and promising applications in human health. Numerous studies have shown that astaxanthin has potential health-promoting effects in the prevention and treatment of various diseases, such as cancers, chronic inflammatory diseases, metabolic syndrome, diabetes, diabetic nephropathy, cardiovascular diseases, gastrointestinal diseases, liver diseases, neurodegenerative diseases, eye diseases, skin diseases, exercise-induced fatigue, male infertility, and HgCl₂-induced acute renal failure. In this article, the currently available scientific literature regarding the most significant activities of astaxanthin is reviewed.
SUMMARY
Toll-like receptors (TLRs) have previously been shown to play critical roles in the activation of innate immunity. Here, we describe that T cell expression of TLR2 regulates T helper 17 (Th17) cell responses. Stimulation with TLR2 agonists promoted Th17 differentiation in vitro and led to more robust proliferation and Th17 cytokine production. Using the experimental autoimmune encephalomyelitis (EAE) model, we found that TLR2 regulated Th17 cell-mediated autoimmunity in vivo and that loss of TLR2 in CD4+ T cells dramatically ameliorated EAE. This study thus reveals a critical role of a TLR in the direct regulation of adaptive immune response and pathogenesis of autoimmune diseases.
Transcription factors of the STAT (signal transducer and activator of transcription) family are critical in the cytokine-mediated functional differentiation of CD4 + helper T cells. Members of the SOCS (suppressor of cytokine signaling) family negatively regulate the activation of STAT proteins; however, their roles in the differentiation and function of helper T cells are not well understood. Here we found that the SOCS protein CIS, which was substantially induced by interleukin 4 (IL-4), negatively regulated the activation of STAT3, STAT5 and STAT6 in T cells. CIS-deficient mice spontaneously developed airway inflammation, and CIS deficiency in T cells led to greater susceptibility to experimental allergic asthma. CIS-deficient T cells showed enhanced differentiation into the T H 2 and T H 9 subsets of helper T cells. STAT5 and STAT6 regulated IL-9 expression by direct binding to its gene. Our data thus demonstrate a critical role for CIS in controlling proallergic generation of helper T cells.
How naïve CD4+ T cells commit to the T helper type 2 (TH2) lineage is poorly understood. Here we show that the basic helix-loop-helix transcription factor Dec2 is selectively expressed in TH2 cells. CD4+ T cells from Dec2-deficient mice exhibits defective TH2 differentiation in vitro and in vivo in an asthma model and in response to challenge with a parasite antigen. Dec2 promotes interleukin 4 (IL-4), IL-5 and IL-13 expression during early TH2 differentiation, and directly binds to and activates transcription of the Junb and Gata3 genes. As GATA3 induces Dec2 expression, these findings also indicate a feed-forward regulatory circuit during TH2 differentiation.
GERD (gastroesophageal reflux disease) is a frequent consideration in ICU neonates. We tested the hypothesis that symptoms in GERD are dependent on the spatio-temporal and physico-chemical characteristics of reflux events by evaluating the symptom sensitivity index (SSI) and symptom index (SI) in relation to the refluxate characteristics. Thirty symptomatic neonates (30.7±0.8 wk gestation) were evaluated using manometry and pH-Impedance methods. During 704.3 hr of recordings, 2,063 GER (gastroesophageal reflux) were observed; 54% of the GER were associated with symptoms. Defined by physical characteristics, there were 51.3% liquid, 29.1% gas, and 19.6% mixed GER. Defined by chemical characteristics, there were 48.5% acid- and 51.5% non-acid GER. Defined by most proximal extent, 79.2% were supra-UES (upper esophageal sphincter), 20.8% were infra-UES. Higher SSI was noted with pH-only events (P<0.0001 vs. pH-Impedance events). Higher SI was noted with movement symptoms (vs. sensory, P=0.04). In a subset analysis, the frequencies of GER events, acid clearance time, and SSI were all greater in chronic lung disease vs. none (P<0.001). In conclusion, clinical significance of symptoms as measured by SSI and SI and characterization of spatial-temporal-physical-chemical nature of GER events as defined by pH-impedance methods clarifies the definition of GERD.
We defined the sensory-motor characteristics of the lower esophageal sphincter relaxation (LESR) (stimulus threshold volume, response onset, and relaxation period, relaxation magnitude, nadir) during maturation in human neonates. We hypothesized that LESR kinetics differs during maturation and with peristaltic reflex type. Basal and adaptive esophageal motility testing was performed (N = 20 premature neonates) at 34.7 and 39.1 wk (time 1 and time 2). Effects of midesophageal provocation with graded stimuli (N = 1,267 stimuli, air and liquids) on LESR kinetics during esophagodeglutition response (EDR) and secondary peristalsis (SP) were analyzed by mixed models. Frequency of LESR with basal primary peristalsis were different during maturation (P = 0.03). During adaptive responses with maturation, 1) the frequencies of peristaltic reflexes and LESR were similar; 2) liquid stimuli resulted in a shorter LESR response latency and LESR nadir and greater LESR magnitude (all P < 0.05); 3) media differences were noted with LESR response latency (air vs. liquids, P < 0.02); and 4) infusion flow rate-LESR were different (P < 0.01 for air and liquids). Mechanistically, 1) frequency of LESR was greater during peristaltic reflexes at both times (vs. none, P < 0.0001); 2) LESR response latency, duration, and time to complete LESR were longer with EDR (all P < 0.05, vs. SP at time 2); and 3) graded stimulus volume LESR were different for air and liquids (P < 0.01). In conclusion, sensory-motor characteristics of LESR depend on the mechanosensitive properties of the stimulus (media, volume, flow), type of peristaltic reflex, and postnatal maturation. Maturation modulates an increased recruitment of inhibitory pathways that favor LESR.
Aloperine (ALO) is a quinolizidine alkaloid extracted from the leaves of Sophora alopecuroides (S. alopecuroides) and possesses anti-inflammatory, anti-allergenic, antitumor, and antiviral effects. In this study, when compared with seven other types of alkaloids extracted from S. alopecuroides, ALO treatment produced the most potent effects against HCT116 colon cancer cell types. ALO inhibited proliferation and induced apoptosis in HCT116 cells in a dose- and time-dependent manner as detected by MTT, clonogenic survival, and flow cytometric assays. Results of the western blot analysis and qPCR revealed that ALO increased the protein and mRNA of Bax and decreased Bcl-2 via the mitochondrial death pathway. In addition, ALO induced cell cycle arrest at the G2/M phase with a concomitant increase in p21 and p53 and a decrease in cyclin D1 and B1. ALO also inhibited phosphatidylinositol 3-kinase/Akt and JAK/Stat3. Generally, ALO exerted a significant anti-proliferative effect via apoptotic and cell cycle arrest induction in HCT116 cells. These results suggested that ALO should be investigated further as an agent of chemotherapeutic activity in human colon cancer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.