Edible red seaweed Campylaephora hypnaeoides J. Agardh alleviates obesity and related metabolic disorders in mice by suppressing oxidative stress and inflammatory response

Background The obesity epidemic has become a serious public health problem in many countries worldwide. Seaweed has few calories and is rich in active nutritional components necessary for health promotion and disease prevention. The aim of this study was to investigate the effects of the Campylaephora hypnaeoides J. Agardh (C. hypnaeoides), an edible seaweed traditionally eaten in Japan, on high-fat (HF) diet-induced obesity and related metabolic diseases in mice. Methods Male C57BL/6J mice were randomly divided into the following groups: normal diet group, HF diet group, HF diet supplemented with 2% C. hypnaeoides, and HF diet supplemented with 6% C. hypnaeoides. After 13 weeks of treatment, the weight of the white adipose tissue and liver, and the serum levels of glucose, insulin, adipokines, and lipids were measured. Hepatic levels of adipokines, oxidant markers, and antioxidant markers were also determined. Insulin resistance was assessed by a glucose tolerance test. Polysaccharides of C. hypnaeoides were purified and their molecular weight was determined by high-performance seize exclusion chromatography. The anti-inflammatory effects of purified polysaccharides were evaluated in RAW264.7 cells. Results Treatment of HF diet-induced obese mice with C. hypnaeoides for 13 weeks suppressed the increase in body weight and white adipose tissue weight. It also ameliorated insulin resistance, hyperglycemia, hepatic steatosis, and hypercholesterolemia. The ingestion of an HF diet increased serum levels of malondialdehyde (MDA), tumor necrosis factor α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1), while it decreased serum adiponectin levels. In the liver, an HF diet markedly increased the MDA, TNF-α, and interleukin-6 (IL-6) levels, while it decreased glutathione and superoxide dismutase. These metabolic changes induced by HF diet feeding were ameliorated by dietary C. hypnaeoides. Purified polysaccharides and ethanol extract from C. hypnaeoides inhibited the lipopolysaccharide-induced overproduction of nitric oxide and TNF-α in macrophage RAW264.7 cells. Conclusions The present results indicated that C. hypnaeoides was able to alleviate HF diet-induced metabolic disorders, including obesity, hyperglycemia, hepatic steatosis, and hypercholesterolemia by attenuating inflammation and improving the antioxidant capacity in mice. Polysaccharides and polyphenols may be involved in these beneficial effects of C. hypnaeoides.

3-Hydroxy-5,6-epoxy-β-ionone Isolated from Invasive Harmful Brown Seaweed Sargassum Horneri Protects MH-S Mouse Lung Cells from Urban Particulate Matter-Induced Inflammation

Air pollution is a process that mixes pollutants into the atmosphere, which is potentially harmful to humans and causes negative impacts on the surrounding environment (biotic and abiotic). The negative health effects associated with air pollution have been reported from both indoor and outdoor environments. Specifically, dust storms originating in Chinese and Mongolian desert areas introduce significant amounts of particulate matter (PM) to the Korean atmosphere. Previously, several studies reported that urban PM (UPM) is a potential agent that causes inflammation in the lungs by altering multiple signal transduction pathways; therefore, screening and identification of anti-inflammatory compounds against UPM-induced inflammation is an urgent requirement. In the present study, we attempted to study the anti-inflammatory properties of 3-Hydroxy-5,6-epoxy-β-ionone (HEBI), a pure compound isolated from invasive brown seaweed, Sargassum horneri (brown edible seaweed), against UPM-stimulated lung macrophages (MH-S). Anti-inflammatory parameters of HEBI were evaluated using Western blots, ELISA, RT-qPCR, and MTT assays. According to the results, HEBI at concentrations between 31.3 and 125 µg/mL reduced UPM-induced NO, PGE2, and pro-inflammatory cytokine production via blocking the downstream signal transduction of NF-κB and MAPKs. Specifically, HEBI down-regulated the mRNA expression levels of Toll-like receptors 2 and 4, which are well-known NF-κB and MAPKs stimulators. Taken together, HEBI is a potential candidate to develop functional foods and active ingredients in cosmeceuticals because of its profound effects against UPM-induced inflammation in MH-S macrophages.

Microbiological Food Safety of Seaweeds

The use of seaweeds in the human diet has a long history in Asia and has now been increasing also in the western world. Concurrent with this trend, there is a corresponding increase in cultivation and harvesting for commercial production. Edible seaweed is a heterogenous product category including species within the green, red, and brown macroalgae. Moreover, the species are utilized on their own or in combinatorial food products, eaten fresh or processed by a variety of technologies. The present review summarizes available literature with respect to microbiological food safety and quality of seaweed food products, including processing and other factors controlling these parameters, and emerging trends to improve on the safety, utilization, quality, and storability of seaweeds. The over- or misuse of antimicrobials and the concurrent development of antimicrobial resistance (AMR) in bacteria is a current worldwide health concern. The role of seaweeds in the development of AMR and the spread of antimicrobial resistance genes is an underexplored field of research and is discussed in that context. Legislation and guidelines relevant to edible seaweed are also discussed.

The edible seaweed Laminaria japonica contains cholesterol analogues that inhibit Lipid Peroxidation and Cyclooxygenase Enzymes

In this study, 5 sterols were isolated and purified from Laminaria japonica, commonly known as edible brown seaweed, and their structures were identified based on detailed chemical methods and spectroscopic analyses. Spectroscopic analyses characterized 5 sterols as 29-Hydroperoxy-stigmasta-5,24(28)-dien-3β-ol, saringosterol (24-vinyl-cholest-5-ene-3β,24-diol), 24-methylenecholesterol, fucosterol (stigmasta-5,24-diene-3β-ol), and 24-Hydroperoxy-24-vinyl-cholesterol. The bioactivities of these sterols were tested using lipid peroxidation (LPO) and cyclooxygenase (COX-1 and −2) enzyme inhibitory assays. Fucosterol exhibited the highest COX-1 and −2 enzyme inhibitory activities at 59 and 47%, respectively. Saringosterol, 24-methylenecholesterol and fucosterol showed higher LPO inhibitory activity at >50% than the other compounds. In addition, the results of molecular docking revealed that the 5 sterols were located in different pocket of COX-1 and −2 and fucosterol with tetracyclic skeletons and olefin methine achieved the highest binding energy (−7.85 and −9.02 kcal/mol) through hydrophobic interactions and hydrogen bond. Our results confirm the presence of 5 sterols in L. japonica and its significant anti-inflammatory and antioxidant activity.Graphical abstractHighlightsSterols 29-hydroperoxy-stigmasta-5,24(28)-dien-3β-ol and 24-hydroperoxy-24-vinyl-cholesterol are identified for the first time in L. japonica.Saringosterol, 24-methylenecholesterol and fucosterol showed strong LPO inhibitory activity.Fucosterol showed highest binding affinity for COX-1 and −2 enzymes through hydrophobic interactions.

Edible Red Seaweed Campylaephora Hypnaeoides J. Agardh Alleviates Obesity and Related Metabolic Disorders in Mice by Suppressing Oxidative Stress and Inflammatory Response

Background: The obesity epidemic has become a serious public health problem in many countries worldwide. Seaweed has few calories and is rich in active nutritional components necessary for health promotion and disease prevention. The aim of this study was to investigate the effects of the Campylaephora hypnaeoides J. Agardh (C. hypnaeoides), an edible seaweed traditionally eaten in Japan, on high-fat (HF) diet-induced obesity and related metabolic diseases in mice.Methods: Male C57BL/6J mice were randomly divided into the following groups: normal diet group, HF diet group, HF diet supplemented with 2% C. hypnaeoides, and HF diet supplemented with 6% C. hypnaeoides. After 13 weeks of treatment, the weight of the white adipose tissue and liver, and the serum levels of glucose, insulin, adipokines, and lipids were measured. Hepatic levels of adipokines, oxidant markers, and antioxidant markers were also determined. Insulin resistance was assessed by a glucose tolerance test. Polysaccharides of C. hypnaeoides were purified and their molecular weight was determined by high-performance seize exclusion chromatography. The anti-inflammatory effects of purified polysaccharides were evaluated in RAW264.7 cells. Results: Treatment of HF diet-induced obese mice with C. hypnaeoides for 13 weeks suppressed the increase in body weight and white adipose tissue weight. It also ameliorated insulin resistance, diabetes, hepatic steatosis, and hypercholesterolemia. The ingestion of an HF diet increased serum levels of malondialdehyde (MDA), tumor necrosis factor a (TNF-a), and monocyte chemoattractant protein-1 (MCP-1), while it decreased serum adiponectin levels. In the liver, an HF diet markedly increased the MDA, TNF-a, and interleukin-6 (IL-6) levels, while it decreased glutathione (GSH) and superoxide dismutase (SOD). These metabolic changes induced by HF diet feeding were ameliorated by dietary C. hypnaeoides. Purified polysaccharides and ethanol extract from C. hypnaeoides inhibited the lipopolysaccharide-induced overproduction of nitric oxide and TNF-a in macrophage RAW264.7 cells. Conclusions: The present results indicated that C. hypnaeoides was able to alleviate HF diet-induced metabolic disorders, including obesity, diabetes, hepatic steatosis, and hypercholesterolemia by attenuating inflammation and improving the antioxidant capacity in mice. Polysaccharides and polyphenols may be involved in these beneficial effects of C. hypnaeoides.

1524 Design and Implementation Of ICE-COVID, A Double-Blind Randomised Placebo-Controlled Trial on The Efficacy of Iota-Carrageenan Nasal and Throat Spray for Covid-19 Prophylaxis

Introduction The severity of Covid-19 infection is associated with viral load. For infection to occur, viruses including SARS-CoV-2 must first penetrate the respiratory mucus to attach to the host cell surface receptors. Iota-carrageenan (I-C), a sulphated polysaccharide extracted from red edible seaweed, has shown efficacy against a range of viruses in clinical trials, through prevention of viral entry into respiratory host cells and in-vitro activity against SARS-CoV-2. Our aim, as an academic surgical department, was to design and implement a clinical trial to investigate whether I-C nasal and throat sprays are effective in reducing the rate and severity of Covid-19 infection. Method The study is a single centre, double-blinded randomised controlled trial. Recruitment of 480 participants aged ≥18 years without previous Covid-19 infection and who have not yet been vaccinated, commenced in December 2020. Participants are randomised to either the treatment (0.12% I-C in 0.5% saline spray) or placebo (0.5% saline spray) arm and will prophylactically apply the spray to their nose and throat while completing a daily symptom tracker for a total of 10 weeks. The primary outcome is the acquisition of Covid-19 infection. Secondary outcomes include symptom type, severity and duration, subsequent familial/household Covid-19 infection and infection with non-Covid-19 upper respiratory tract infections. Discussion Our hypothesis is that I-C sprays will reduce SARS-CoV-2 attachment to the naso- and oropharyngeal mucosal epithelial cells thus reducing the effective viral infective dose. If proven effective, the self-administered prophylactic spray would have wider utility for key workers and the general population. Trial registration number NCT04590365

Nutritional Profile, Antioxidative and Antihyperglycemic Properties of Padina tetrastromatica from Tioman Island, Malaysia

Seaweeds are an important ingredient of functional foods recommended for daily food, due to their unique compositions and nutritional value. Padina tetrastromatica is a brown edible seaweed that is commonly found along the coastal regions of Peninsular Malaysia and consumed as food by some coastal communities. This study investigates the nutritional and antihyperglycaemic potential of P. tetrastromatica extracts, which is generally accepted as an important functional food. In our methodology, we induced diabetes intraperitoneally in experimental animals with a dose of 65 mg kg−1 body weight of streptozotocin. Oral treatment with 200 and 400 mg kg−1 of P. tetrastromatica ethanolic and ethyl acetate extracts were initiated, respectively, to experimental rats once daily for 18 days. Metformin was used as the positive control. Biochemical estimations and histopathological analysis were included in this study. Treatment with P. tetrastromatica extracts significantly lowered the plasma glucose levels in Streptozotocin-induced diabetic rats. In addition, P. tetrastromatica extract treatment also showed a significant reduction in serum alanine transaminase levels. However, no significant changes were observed in serum aspartate transaminase levels. The ethyl acetate extract of P. tetrastromatica at 400 mg kg−1 dose shows some nephroprotective effect, which is observed from the significant increase in the plasma albumin levels. Histopathological evaluation revealed no marked morphological changes in tissues of the isolated organs of the ethyl acetate extract-treated group, revealing the safe nature of P. tetrastromatica.