Effects of brown seaweed polyphenols, a class of phlorotannins, on metabolic disorders via regulation of fat function

Beneficial effects of seaweed-derived components on metabolic syndrome via gut microbiota modulation

Metabolic syndrome comprises a group of conditions that collectively increase the risk of abdominal obesity, diabetes, atherosclerosis, cardiovascular diseases, and cancer. Gut microbiota is involved in the pathogenesis of metabolic syndrome, and microbial diversity and function are strongly affected by diet. In recent years, epidemiological evidence has shown that the dietary intake of seaweed can prevent metabolic syndrome via gut microbiota modulation. In this review, we summarize the current in vivo studies that have reported the prevention and treatment of metabolic syndrome via seaweed-derived components by regulating the gut microbiota and the production of short-chain fatty acids. Among the surveyed related articles, animal studies revealed that these bioactive components mainly modulate the gut microbiota by reversing the Firmicutes/Bacteroidetes ratio, increasing the relative abundance of beneficial bacteria, such as Bacteroides, Akkermansia, Lactobacillus, or decreasing the abundance of harmful bacteria, such as Lachnospiraceae, Desulfovibrio, Lachnoclostridium. The regulated microbiota is thought to affect host health by improving gut barrier functions, reducing LPS-induced inflammation or oxidative stress, and increasing bile acid production. Furthermore, these compounds increase the production of short-chain fatty acids and influence glucose and lipid metabolism. Thus, the interaction between the gut microbiota and seaweed-derived bioactive components plays a critical regulatory role in human health, and these compounds have the potential to be used for drug development. However, further animal studies and human clinical trials are required to confirm the functional roles and mechanisms of these components in balancing the gut microbiota and managing host health.

Thinned young apple polyphenols may prevent neuronal apoptosis by up-regulating 5-hydroxymethylcytosine in the cerebral cortex of high-fat diet-induced diabetic mice

Apple polyphenols exert neuroprotective effects by improving the mitochondrial tricarboxylic acid (TCA) cycle function, but the details of their mechanisms are still not fully understood. TCA cycle metabolites regulate the level of 5-hydroxymethylcytosine (5hmC) by affecting the ten-eleven translocation (TET) enzyme activity. Therefore, we hypothesized that thinned young apple polyphenols (TYAPs) inhibit neuronal apoptosis by up-regulating the level of 5hmC in the cerebral cortex of high-fat diet-induced diabetic mice. C57BL/6J mice were randomly divided into 5 groups (n = 10 each group): the control (CON) group, the high-fat diet (HFD, negative control) group, the lovastatin (LOV, positive drug control) group, the resveratrol (RES, positive polyphenol control) group and the TYAP group during an eight-week intervention. The presented results verified that in the HFD group, the level of 5hmC and the expression of TET2 in the cerebral cortex were significantly lower, and the ratio of (succinic acid + fumaric acid)/α-ketoglutarate and the neuronal apoptosis rate were significantly higher than those in the CON group. However, TYAP intervention effectively restored the level of 5hmC through up-regulating the expression and activity of TET2, so as to improve diabetes symptoms and prevent diabetes-induced neuronal apoptosis.

Marine natural products

Covering: January to December 2021This review covers the literature published in 2021 for marine natural products (MNPs), with 736 citations (724 for the period January to December 2021) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1425 in 416 papers for 2021), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of the number of authors, their affiliations, domestic and international collection locations, focus of MNP studies, citation metrics and journal choices is discussed.

Marine Polyphenol Phlorotannins as a Natural Sleep Aid for Treatment of Insomnia: A Review of Sedative-Hypnotic Effects and Mechanism of Action

Insomnia is a common sleep disorder. Natural sleep aids are gaining worldwide popularity as alternatives to prescription drugs for improving sleep. Recently, numerous studies have investigated the sedative-hypnotic effects of the polyphenols of terrestrial plants. The hypnotic effects of marine polyphenols have also been studied in recent years. Phlorotannins are marine polyphenols that are found only in brown algae. Phlorotannins exert sedative-hypnotic effects via the gamma-aminobutyric acid type A-benzodiazepine receptor. In addition, the brown seaweed Ecklonia cava supplement containing phlorotannins has been approved by the Ministry of Food and Drug Safety as a health-functional ingredient that helps improve sleep quality. Currently, it is meaningful to deal with the sedative-hypnotic effects of phlorotannins as natural sleep aids. The current review comprehensively presents the sedative-hypnotic effects in animal models and human clinical trials as well as their mechanism of action, extraction, purification, and safety.

Brown algae and barley-based anti-obesity food and its safety in C57BL6 mice

Brown algae have been considered a potential source of bioactives and used as a dietary supplement to manage obesity and its associated health complications. However, its effective use is limited due to heavy metals and microbial contamination, unawareness of health benefits and limited dietary exploitation. We developed, the Indian brown algae Padina tetrastromatica and barley-based anti-obesity food (AOF) and examined for microbial and heavy metal safety. Additionally, acute [0 (control), 50, 100, 200, 500 g AOF/kg diet] and sub-acute [0, 5, 50 g AOF/kg diet] doses of AOF were fed to C57BL6 mice and toxicity was examined. The physical, locomotory, hematological, biochemical parameters and histopathology were examined. Postprandial plasma and tissue levels of fucoxanthin and its metabolites were analyzed. Feeding AOF did not affect the general behavior, food and water intake, growth or survival of animals. Biochemical indices did not show any differences between AOF-fed and control groups. However, significantly lower levels of plasma cholesterol and triglycerides in groups fed 5 and 50 g of AOF/kg diet were observed. The post-mortem examination revealed no macroscopic/microscopic alteration in the vital organs. Overall, results validate that AOF is a safe and effective dietary supplement (even at higher doses of 500 g AOF/kg) to mitigate obesity.

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Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05483-4.

Polyphenols in Metabolic Diseases

Polyphenols (PPs) are a large group of phytochemicals containing phenolic rings with two or more hydroxyl groups. They possess powerful antioxidant properties, multiple therapeutic effects, and possible health benefits in vivo and in vitro, as well as reported clinical studies. Considering their free-radical scavenging and anti-inflammatory properties, these substances can be used to treat different kinds of conditions associated with metabolic disorders. Many symptoms of metabolic syndrome (MtS), including obesity, dyslipidemia, atherosclerosis, elevated blood sugar, accelerating aging, liver intoxication, hypertension, as well as cancer and neurodegenerative disorders, are substantially relieved by dietary PPs. The present study explores the bioprotective properties and associated underlying mechanisms of PPs. A detailed understanding of these natural compounds will open up new opportunities for producing unique natural PP-rich dietary and medicinal plans, ultimately affirming their health benefits.

Inhibitory Effects of Polyphenols-Rich Components From Three Edible Seaweeds on Inflammation and Colon Cancer in vitro

Polyphenols from edible seaweeds display various health benefits which have not been adequately studied. This study aimed to characterize the composition of extractable polyphenol-rich components (EPCs) and non-extractable polyphenol-rich components (NEPCs) from three edible seaweeds (i.e., Laminaria japonica, Ulva lactuca, and Porphyra tenera) and evaluate their anti-inflammatory capacities in activated macrophages and anticancer properties in colon cancer cells. Both EPCs and NEPCs from three edible seaweeds against lipopolysaccharides (LPS) stimulated nitric oxide in activated macrophages. Immunoblotting and qRT-PCR indicated that EPCs and NEPCs regulated the expression levels of proinflammatory enzymes, proinflammatory cytokines, and antioxidant enzymes in macrophages. Furthermore, EPCs and NEPCs lowered the viability of colon cancer cells, while normal colon cells were not affected. Additionally, EPCs and NEPCs induced cellular apoptosis and led to G0/G1 cell cycle arrest in HCT116 cells. Overall, these results provide a rationale for future animal and human studies designed to examine the anti-inflammatory and chemopreventive capacities of polyphenols-rich components from L. japonica, U. lactuca, and P. tenera.

Protective effects of apple polyphenols on bone loss in mice with high fat diet-induced obesity

Obesity-induced inflammation can lead to an imbalance in bone formation and resorption. Our previous studies have demonstrated that apple polyphenols (AP) can reduce body weight and inflammation. But its effect...

Seaweed consumption in France: Key data for exposure and risk assessment

Seaweeds accumulate toxic contaminants present in the surrounding waters such as trace elements, ammonium, dioxins and pesticides. Seaweed consumption data are scarce in France as in Europe. Given that seaweed consumption data are essential to assess exposure and the risks for human health linked to toxic substances, it would appear essential to generate these data. The aim of the study was to assess the current consumption of seaweed foodstuffs by the French population via an online survey conducted on 780 adults (seaweed foodstuffs consumed, percentage of consumers and frequency of consumption). The daily consumption of seaweeds was assessed. Enquiries at points of purchase were also performed to reference the type of foodstuffs found on the French market, the seaweed species present, and the percentage of seaweed in the product. These new data generated in this work will be useful for safety assessors and for safety agencies.