Inhibitory activity of extracts of Hebridean brown seaweeds on lipase activity

Modulatory effects of red seaweeds (Palmaria palmata, Porphyra umbilicalis and Chondrus crispus) on the human gut microbiota via an in vitro model

This work investigated the nutritional and mineral composition of three red seaweed species, Palmaria palmata, Porphyra umbilicalis and Chondrus crispus, and an in vitro assay was performed to determinate the effects of the intake of whole red seaweed on gut microbiota, short chain fatty acids production and metabolic pathways. The results obtained showed that 100 g of seaweeds contained essential minerals such as 28-107 % daily needs of Ca, 183-600 % daily needs of Fe and 18-54 % daily needs of Zn, whereas low content were found for Cu and I. Seaweed digestion fermentation showed beneficial effects of gut microbiota, as increases in beneficial species such as Akkermansia muciniphila, and in some seaweed, Bifidobacterium adoslescentis, Bacteroides ovatus or Lactobacillus ruminis. Metabolic pathways did only found little significant differences with respect to inulin fermentation. In view of the results, red seaweed showed prebiotic effects on human gut microbiota.

Exploring the Inhibitory Potential of Sodium Alginate Against Digestive Enzymes Linked to Obesity and Type 2 Diabetes

Obesity and type 2 diabetes mellitus (T2DM) are major health concerns worldwide, often managed with treatments that have significant limitations and side effects. This study examines the potential of sodium alginates, extracted from Ecklonia radiata and Sargassum elegans, to inhibit digestive enzymes involved in managing these conditions. We chemically characterized the sodium alginates and confirmed their structural integrity using FTIR, NMR, and TGA. The focus was on evaluating their ability to inhibit key digestive enzymes relevant to T2DM (α-amylase, α-glucosidase, sucrase, maltase) and obesity (pancreatic lipase). Enzyme inhibition assays revealed that these sodium alginates moderately inhibit α-glucosidase, maltase, and lipase by up to 43%, while showing limited effects on sucrase and α-amylase. In addition, the sodium alginates did not affect glucose uptake in human colorectal cells (HCT116), indicating they do not impact cellular glucose absorption. In summary, while the observed enzyme inhibition was moderate, the targeted inhibition of α-glucosidase, maltase, and lipase suggests that sodium alginates could be beneficial for managing postprandial hyperglycemia and lipid absorption in the context of T2DM and obesity.

Alaria esculenta, Ulva lactuca, and Palmaria palmata as Potential Functional Food Ingredients for the Management of Metabolic Syndrome

Hypertension, type 2 diabetes (T2D), and obesity raise an individual's risk of suffering from diseases associated with metabolic syndrome (MS). In humans, enzymes that play a role in the prevention and development of MS include angiotensin converting enzyme (ACE-1) associated with hypertension, α-amylase associated with T2D, and lipase linked to the development of obesity. Seaweeds are a rich source of bioactives consisting of proteins/peptides, polysaccharides, and lipids. This study examined the potential of seaweed-derived bioactives from Alaria esculenta, Ulva lactuca, and Palmaria palmata as inhibitors of ACE-1, α-amylase, and lipase. In vitro enzyme inhibitory assays were used to quantify the bioactivity of the seaweed extracts and compare their half-maximal inhibitory (IC50) values to recognised positive control enzyme inhibitory drugs captopril© (an ACE-1 inhibitor), acarbose (an α-amylase inhibitor), and orlistat (a lipase inhibitor). Three seaweed extracts displayed enzyme inhibitory activities equal to, or more effective than, the reference positive control drugs. These were P. palmata peptides (ACE-1 IC50 94.29 ± 3.07 µg/mL, vs. captopril© 91.83 ± 2.68 µg/mL); A. esculenta polyphenol extract (α-amylase IC50 147.04 ± 9.72 µg/mL vs. acarbose 185.67 ± 12.48 µg/mL, and lipase IC50 106.21 ± 6.53 µg/mL vs. orlistat 139.74 ± 9.33 µg/mL); and U. lactuca polysaccharide extract (α-amylase IC50 168.06 ± 10.53 µg/mL vs. acarbose 185.67 ± 12.48 µg/mL). Proximate analysis also revealed that all three seaweeds were a good source of protein, fibre, and polyunsaturated essential fatty acids (PUFAs). These findings highlight the potential of these seaweeds in the management of diseases associated with MS and as foods.

Bioactivities of Sargassum elegans, Bryopsis myosuroides, Callophyllis variegata seaweeds on diabetes and obesity-related biochemical parameters: A comparative in vitro study

Diabesity' is the occurrence of diabetes in the presence of obesity. Numerous reports have shown that seaweeds possess beneficial biological activities. This study assessed the effects of three seaweeds Bryopsis myosuroides (green), Callophyllis variegata (red), and Sargassum elegans (brown), on diabetes and obesity-related parameters in vitro. The antioxidant potential, carbohydrate and lipid digestive enzyme inhibitory activity, and glucose uptake activities of ethanolic and sulphated polysaccharides (SPs) rich extracts were evaluated. The SP-rich or ethanolic extracts of S. elegans showed the greater inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50 46.6 ± 1.00 g/mL), hydroxyl radical (OH) (IC50 353.70 ± 2.01 μg/mL), and nitric oxide (NO) (IC50 407.5 ± 0.95 μg/mL) compared to other seaweeds. Moreover, the SP-rich extract of S. elegans exhibited higher inhibition of α- glucosidase (IC50 123.8 ± 1.69 μg/mL), whereas B. myosuroides SP-rich extract had better α-amylase (IC50 55.7 ± 0.98 μg/mL) and pancreatic lipase inhibitory activities (IC50 481.1 ± 0.9 μg/mL) compared to other seaweeds. Liquid Chromatography Mass Spectroscopy (LC-MS) was used to identify the compounds present in the seaweed extracts. These include Taxifolin, Amentoflavone-7,4',4″'-Trimethyl Ether, Chrysophenol, and Glucotropaeolin, which have been previously reported to possess biological activities beneficial to human health. Although all three seaweeds evaluated in this study demonstrated antioxidant, digesting enzyme inhibitory and glucose uptake activity to different extents, S. elegans (brown) depicted the highest activity in most assays compared to the other seaweeds. However, further research is required to assess the effects of these seaweed extracts on diabetes and obesity via ex vivo and in vivo experimental animal models.

Intra-Species Variations of Bioactive Compounds of Two Dictyota Species from the Adriatic Sea: Antioxidant, Antimicrobial, Dermatological, Dietary, and Neuroprotective Potential

The marine environment has a significant impact on life on Earth. Organisms residing in it are vital for the ecosystem but also serve as an inexhaustible source of biologically active compounds. Herein, the biodiversity of two brown seaweeds, Dictyota dichotoma and Dictyota fasciola from the Adriatic Sea, was evaluated. The aim of the study was the determination of differences in compound composition while comparing their activities, including antioxidant, antimicrobial, and enzyme inhibition, in connection to human digestion, dermatology, and neurological disorders. Chemical analysis revealed several terpenoids and steroids as dominant molecules, while fucoxanthin was the main identified pigment in both algae. D. dichotoma had higher protein, carbohydrate, and pigment content. Omega-6 and omega-3 fatty acids were identified, with the highest amount of dihomo-γ-linolenic acid and α-linolenic acid in D. dichotoma. Antimicrobial testing revealed a dose-dependent inhibitory activity of methanolic fraction against Escherichia coli and Staphylococcus aureus. Moderate antioxidant activity was observed for both algae fractions, while the dietary potential was high, especially for the D. fasciola dichloromethane fraction, with inhibition percentages of around 92% for α-amylase and 57% for pancreatic lipase at 0.25 mg/mL. These results suggest that Dictyota species might be a potent source of naturally derived agents for obesity and diabetes.

Production and Characterization of Durvillaea antarctica Enzyme Extract for Antioxidant and Anti-Metabolic Syndrome Effects

In this study, three enzyme hydrolysate termed Dur-A, Dur-B, and Dur-C, were produced from Durvillaea antarctica biomass using viscozyme, cellulase, and α-amylase, respectively. Dur-A, Dur-B, and Dur-C, exhibited fucose-containing sulfated polysaccharide from chemical composition determination and characterization by FTIR analyses. In addition, Dur-A, Dur-B, and Dur-C, had high extraction yields and low molecular weights. All extracts determined to have antioxidant activities by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and ferrous ion-chelating methods. All extracts were also able to positively suppress the activities of key enzymes involved in metabolic syndrome: angiotensin I-converting enzyme (ACE), α-amylase, α-glucosidase, and pancreatic lipase. In general, Dur-B exhibited higher antioxidant and higher anti-metabolic syndrome effects as compared to the other two extracts. Based on the above health promoting properties, these extracts (especially Dur-B) can be used as potential natural antioxidants and natural anti-metabolic syndrome agents in a variety of food, cosmetic, and nutraceutical products for health applications.

Investigation of Antioxidant, Hypoglycemic and Anti-Obesity Effects of Euphorbia Resinifera L

Objectives

The aim of this work is to evaluate the in vitro antioxidant, hypoglycemic, and antiobesity effects of Euphorbia resinifera extracts and investigate the phenolic constituents and the toxicity of these extracts.

Methods

Phytochemical screening was performed to detect polyphenols and flavonoids. Antioxidant activity was evaluated by four methods (DPPH, ABTS, H₂O₂, and xanthine oxidase inhibition). The hypoglycemic effect was determined by the inhibition of α-amylase and α-glucosidase enzymes in vitro and via a starch tolerance study in normal rats. The antiobesity effect was estimated by in vitro inhibition of lipase.

Results

Phytochemical screening revealed that the ethanolic extract was rich in polyphenols (99 ± 0.56 mg GEA/g extract) and tannins (55.22 ± 0.17 mg RE/g extract). Moreover, this extract showed higher antioxidant activity in different tests the DPPH assay (IC₅₀ = 53.81 ± 1.83 µg/mL), ABTS assay (111.4 ± 2.64 mg TE/g extract), H₂O₂ (IC₅₀ = 98.15 ± 0.68 µg/mL), and xanthine oxidase (IC₅₀ = 10.26 ± 0.6 µg/mL). With respect to hypoglycemic effect, the aqueous and ethanolic extracts showed IC₅₀ values of 119.7 ± 2.15 µg/mL and 102 ± 3.63 µg/mL for α-amylase and 121.4 ± 1.88 and 56.6 ± 1.12 µg/mL for α-glucosidase, respectively, and the extracts lowered blood glucose levels in normal starch-loaded rats. Additionally, lipase inhibition was observed with aqueous (IC₅₀ = 25.3 ± 1.53 µg/mL) and ethanolic (IC₅₀ = 13.7 ± 3.03 µg/mL) extracts.

Conclusion

These findings show the antioxidant, hypoglycemic, and hyperlipidemic effects of E. resinifera extracts, which should be investigated further to validate their medicinal uses and their pharmaceutical applications.

The seaweed holobiont: from microecology to biotechnological applications

In the ocean, seaweed and microorganisms have coexisted since the earliest stages of evolution and formed an inextricable relationship. Recently, seaweed has attracted extensive attention worldwide for ecological and industrial purposes, but the function of its closely related microbes is often ignored. Microbes play an indispensable role in different stages of seaweed growth, development and maturity. A very diverse group of seaweed‐associated microbes have important functions and are dynamically reconstructed as the marine environment fluctuates, forming an inseparable ‘holobiont’ with their host. To further understand the function and significance of holobionts, this review first reports on recent advances in revealing seaweed‐associated microbe spatial and temporal distribution. Then, this review discusses the microbe and seaweed interactions and their ecological significance, and summarizes the current applications of the seaweed–microbe relationship in various environmental and biological technologies. Sustainable industries based on seaweed holobionts could become an integral part of the future bioeconomy because they can provide more resource‐efficient food, high‐value chemicals and medical materials. Moreover, holobionts may provide a new approach to marine environment restoration.

Algal polysaccharides and derivatives as potential therapeutics for obesity and related metabolic diseases

The potential and challenges of algal polysaccharides and their derivatives as potential therapeutic agents for obesity and its related metabolic diseases.

Marine Ingredients for Sensitive Skin: Market Overview

Marine ingredients are a source of new chemical entities with biological action, which is the reason why they have gained relevance in the cosmetic industry. The facial care category is the most relevant in this industry, and within it, the sensitive skin segment occupies a prominent position. This work analyzed the use of marine ingredients in 88 facial cosmetics for sensitive skin from multinational brands, as well as their composition and the scientific evidence that supports their efficacy. Marine ingredients were used in 27% of the cosmetic products for sensitive skin and included the species Laminaria ochroleuca, Ascophyllum nodosum (brown macroalgae), Asparagopsis armata (red macroalgae), and Chlorella vulgaris (microalgae). Carotenoids, polysaccharides, and lipids are the chemical classes highlighted in these preparations. Two ingredients, namely the Ascophyllum nodosum extract and Asparagopsis armata extracts, present clinical evidence supporting their use for sensitive skin. Overall, marine ingredients used in cosmetics for sensitive skin are proposed to reduce skin inflammation and improve the barrier function. Marine-derived preparations constitute promising active ingredients for sensitive skin cosmetic products. Their in-depth study, focusing on the extracted metabolites, randomized placebo-controlled studies including volunteers with sensitive skin, and the use of extraction methods that are more profitable may provide a great opportunity for the cosmetic industry.

Optimization of Ultrasound-Assisted Extraction of Bioactive Compounds from Pelvetia canaliculata to Sunflower Oil

In this study, Pelvetia canaliculata L. macroalga, collected from the Atlantic Portuguese coast, was used as a source of bioactive compounds, mostly antioxidants, to incorporate them in sunflower oil with the aim of increasing its biological value and oxidative stability. The lyophilized alga was added to the oil, and ultrasound-assisted extraction (UAE) was performed. Algae concentration and UAE time varied following a central composite rotatable design (CCRD) to optimize extraction conditions. The following parameters were analyzed in the oils: oxidation products, acidity, color, chlorophyll pigments, carotenoids, flavonoids, total phenolic content, antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and sensory analysis. Extraction conditions did not affect the acidity and the amount of oxidation products in the oil. Chlorophylls and carotenoid contents increased with algae concentration, while flavonoid extraction did not depend on algae content or UAE time. Total phenolics in the oil were highly related only to FRAP antioxidant activity. Storage experiments of supplemented oil (12.5% algae; 20 min UAE) were carried out under accelerated oxidation conditions at 60 °C/12 days. Antioxidant activity (FRAP) of supplemented oil was 6-fold higher than the value of non-supplemented oil. Final samples retained 40% of their initial antioxidant activity. The presence of algae extracts contributed to the increased oxidative stability of sunflower oil.

Potential and applications of capillary electrophoresis for analyzing traditional Chinese medicine: a critical review

Capillary electrophoresis (CE) presents a promising possibility for analyzing traditional Chinese medicine (TCM) due to its low reagent consumption, high analysis speed, and enhanced efficiency. Herein we review the employment of CE for analyzing the effective components in TCM and identifying TCM via a fingerprint. Furthermore, we discuss the application of state-of-the-art capillary electrophoresis modes for screening enzyme inhibitors and investigating the interactions between TCM and plasma proteins. The review concludes with recommendations for future studies and improvements in this field of research. The general development trend identified in this review indicates that the application of CE has significantly improved TCM assay performance.

Prebiotic Effects of Seaweed Polysaccharides in Pigs

To ensure environmental sustainability, according to the European Green Deal and to boost the One Health concept, it is essential to improve animals' health and adopt sustainable and natural feed ingredients. Over the past decade, prebiotics have been used as an alternative approach in order to reduce the use of antimicrobials, by positively affecting the gut microbiota and decreasing the onset of several enteric diseases in pig. However, dietary supplementation with seaweed polysaccharides as prebiotics has gained attention in recent years. Seaweeds or marine macroalgae contain several polysaccharides: laminarin, fucoidan, and alginates are found in brown seaweeds, carrageenan in red seaweeds, and ulvan in green seaweeds. The present review focuses on studies evaluating dietary seaweed polysaccharide supplementation in pig used as prebiotics to positively modulate gut health and microbiota composition.

Evaluation of Ultrasound, Microwave, Ultrasound-Microwave, Hydrothermal and High Pressure Assisted Extraction Technologies for the Recovery of Phytochemicals and Antioxidants from Brown Macroalgae

This study aims to explore novel extraction technologies (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ultrasound-microwave-assisted extraction (UMAE), hydrothermal-assisted extraction (HAE) and high-pressure-assisted extraction (HPAE)) and extraction time post-treatment (0 and 24 h) for the recovery of phytochemicals and associated antioxidant properties from Fucus vesiculosus and Pelvetia canaliculata. When using fixed extraction conditions (solvent: 50% ethanol; extraction time: 10 min; algae/solvent ratio: 1/10) for all the novel technologies, UAE generated extracts with the highest phytochemical contents from both macroalgae. The highest yields of compounds extracted from F. vesiculosus using UAE were: total phenolic content (445.0 ± 4.6 mg gallic acid equivalents/g), total phlorotannin content (362.9 ± 3.7 mg phloroglucinol equivalents/g), total flavonoid content (286.3 ± 7.8 mg quercetin equivalents/g) and total tannin content (189.1 ± 4.4 mg catechin equivalents/g). In the case of the antioxidant activities, the highest DPPH activities were achieved by UAE and UMAE from both macroalgae, while no clear pattern was recorded in the case of FRAP activities. The highest DPPH scavenging activities (112.5 ± 0.7 mg trolox equivalents/g) and FRAP activities (284.8 ± 2.2 mg trolox equivalents/g) were achieved from F. vesiculosus. Following the extraction treatment, an additional storage post-extraction (24 h) did not improve the yields of phytochemicals or antioxidant properties of the extracts.

On the Health Benefits vs. Risks of Seaweeds and Their Constituents: The Curious Case of the Polymer Paradigm

To exploit the nutraceutical and biomedical potential of selected seaweed-derived polymers in an economically viable way, it is necessary to analyze and understand their quality and yield fluctuations throughout the seasons. In this study, the seasonal polysaccharide yield and respective quality were evaluated in three selected seaweeds, namely the agarophyte Gracilaria gracilis, the carrageenophyte Calliblepharis jubata (both red seaweeds) and the alginophyte Sargassum muticum (brown seaweed). It was found that the agar synthesis of G. gracilis did not significantly differ with the seasons (27.04% seaweed dry weight (DW)). In contrast, the carrageenan content in C. jubata varied seasonally, being synthesized in higher concentrations during the summer (18.73% DW). Meanwhile, the alginate synthesis of S. muticum exhibited a higher concentration (36.88% DW) during the winter. Therefore, there is a need to assess the threshold at which seaweed-derived polymers may have positive effects or negative impacts on human nutrition. Furthermore, this study highlights the three polymers, along with their known thresholds, at which they can have positive and/or negative health impacts. Such knowledge is key to recognizing the paradigm governing their successful deployment and related beneficial applications in humans.

Aquaculture Production of the Brown Seaweeds Laminaria digitata and Macrocystis pyrifera: Applications in Food and Pharmaceuticals

Seaweeds have a long history of use as food, as flavouring agents, and find use in traditional folk medicine. Seaweed products range from food, feed, and dietary supplements to pharmaceuticals, and from bioenergy intermediates to materials. At present, 98% of the seaweed required by the seaweed industry is provided by five genera and only ten species. The two brown kelp seaweeds Laminaria digitata, a native Irish species, and Macrocystis pyrifera, a native New Zealand species, are not included in these eleven species, although they have been used as dietary supplements and as animal and fish feed. The properties associated with the polysaccharides and proteins from these two species have resulted in increased interest in them, enabling their use as functional foods. Improvements and optimisations in aquaculture methods and bioproduct extractions are essential to realise the commercial potential of these seaweeds. Recent advances in optimising these processes are outlined in this review, as well as potential future applications of L. digitata and, to a greater extent, M. pyrifera which, to date, has been predominately only wild-harvested. These include bio-refinery processing to produce ingredients for nutricosmetics, functional foods, cosmeceuticals, and bioplastics. Areas that currently limit the commercial potential of these two species are highlighted.

The Edible Brown Seaweed Sargassum horneri (Turner) C. Agardh Ameliorates High-Fat Diet-Induced Obesity, Diabetes, and Hepatic Steatosis in Mice

Sargassum horneri (Turner) C. Agardh (S. horneri) is edible brown seaweed that grows along the coast of East Asia and has been traditionally used as a folk medicine and a local food. In this study, we evaluated the effects of S. horneri on the development of obesity and related metabolic disorders in C57BL/6J mice fed a high-fat diet. S. horneri was freeze-dried, fine-powdered, and mixed with a high-fat diet at a weight ratio of 2% or 6%. Feeding a high-fat diet to mice for 13 weeks induced obesity, diabetes, hepatic steatosis, and hypercholesterolemia. Supplementation of mice with S. horneri suppressed high-fat diet-induced body weight gain and the accumulation of fat in adipose tissue and liver, and the elevation of the serum glucose level. In addition, S. horneri improved insulin resistance. An analysis of the feces showed that S. horneri stimulated the fecal excretion of triglyceride, as well as increased the fecal polysaccharide content. Furthermore, extracts of S. horneri inhibited the activity of pancreatic lipase in vitro. These results showed that S. horneri can ameliorate diet-induced metabolic diseases, and the effect may be partly associated with the suppression of intestinal fat absorption.

Safety evidence on the administration of Fucus vesiculosus L. (bladderwrack) extract and lamotrigine: data from pharmacokinetic studies in the rat

Fucus vesiculosus is often incorporated in weight loss dietary supplements to improve weight loss in overweight adults. Obesity is a common condition in epilepsy patients and is indeed increasing in refractory epilepsy and in patients under polytherapy. Since lamotrigine (LTG) is a first-line antiepileptic drug, used in monotherapy or adjunctive therapy, the main objective of this work was to investigate the potential pharmacokinetic-based interactions between F. vesiculosus and LTG in rats. In a first pharmacokinetic study, a single oral dose of F. vesiculosus extract (575 mg/kg, p.o.) was co-administered with a single-dose of LTG (10 mg/kg, p.o.). In a second study, rats were orally pretreated with F. vesiculosus extract (575 mg/kg/day, p.o.) for 14 days and received LTG (10 mg/kg, p.o.) on the 15th day. In the control groups, rats received water instead of the extract. After LTG administration, blood samples were taken until 96 h post-dose, and LTG concentrations measured in plasma were submitted to a non-compartmental pharmacokinetic analysis. The co-administration of F. vesiculosus extract and LTG caused no significant changes in the drug kinetics. However, the repeated pretreatment with F. vesiculosus extract significantly reduced the peak concentrations of LTG and caused a slightly decrease in the extent of systemic drug exposure. Overall, based on these results, no significant clinical impact is expected from the administration of F. vesiculosus dietary supplements and LTG.

Effects of dietary kelp (Ascophylum nodosum) supplementation on survival rate and reproductive performance of mink challenged with Aleutian mink disease virus

Infection with Aleutian mink disease virus (AMDV) has negative effects on reproductive performance and survival rate of American mink (Neovison vison). The objectives of this study were to assess the effects of kelp (Ascophylum nodosum) supplementation on survival, growth rate, and reproductive performance of mink challenged with AMDV. AMDV-free female black mink (n = 75) were intranasally inoculated with a local AMDV strain. Mink were fed a commercial pellet supplemented with 1.5% or 0.75% kelp or were kept as controls (received no kelp) for 451 d. Body weight and rectal temperature were recorded on days 0, 31, 56, 99, 155, 366, and 451 post inoculation (PI). Annual mortality rates were 13.6%, 20.0%, and 31.8% for mink fed 1.5%, 0.75%, or 0.0% kelp, respectively (P = 0.29). Mink which were fed 1.5% kelp had a significantly (P < 0.01) greater daily weight loss during breeding and post-breeding periods (days 155–366 PI), and outperformed (P < 0.01) the other groups in regard to litter sizes at birth and weaning. Differences among treatments were not significant for the number of females mated, or whelped of those exposed to males, kit survival from birth to weaning, or rectal temperature. It was concluded that 1.5% kelp supplementation had beneficial effects on survival rate of adult mink and litter size.

Animal-Origin Prebiotics Based on Chitin: An Alternative for the Future? A Critical Review

The human gut microbiota has been revealed in recent years as a factor that plays a decisive role in the maintenance of human health, as well as in the development of many non-communicable diseases. This microbiota can be modulated by various dietary factors, among which complex carbohydrates have a great influence. Although most complex carbohydrates included in the human diet come from vegetables, there are also options to include complex carbohydrates from non-vegetable sources, such as chitin and its derivatives. Chitin, and its derivatives such as chitosan can be obtained from non-vegetable sources, the best being insects, crustacean exoskeletons and fungi. The present review offers a broad perspective of the current knowledge surrounding the impacts of chitin and its derived polysaccharides on the human gut microbiota and the profound need for more in-depth investigations into this topic. Overall, the effects of whole insects or meal on the gut microbiota have contradictory results, possibly due to their high protein content. Better results are obtained for the case of chitin derivatives, regarding both metabolic effects and effects on the gut microbiota composition.

Lipase Inhibitors for Obesity: A Review

With the rapid increase in the population of obese individuals, obesity has become a global problem. Many kinds of chronic metabolic diseases easily caused by obesity have received increasing attention from researchers. People are also striving to find various safe and effective treatment methods as well as anti-obesity medicines. Pancreatic lipase (PL) inhibitors have received substantial attention from researchers in recent years, and PL inhibitors from natural products have attracted much attention due to their structural diversity, low toxicity and wide range of sources. They have been used in the intestinal tract, blood, and the central nervous system with no side effects, and these advantages could lead to a new generation of diet pills or health care products with great development potential. This article is mainly aimed at discussing the research of obesity drug treatment with PL inhibitors and offers a brief review of related properties and the use of PL inhibitors in the field of weight loss.

Potential Use of Marine Seaweeds as Prebiotics: A Review

Human gut microbiota plays an important role in several metabolic processes and human diseases. Various dietary factors, including complex carbohydrates, such as polysaccharides, provide abundant nutrients and substrates for microbial metabolism in the gut, affecting the members and their functionality. Nowadays, the main sources of complex carbohydrates destined for human consumption are terrestrial plants. However, fresh water is an increasingly scarce commodity and world agricultural productivity is in a persistent decline, thus demanding the exploration of other sources of complex carbohydrates. As an interesting option, marine seaweeds show rapid growth and do not require arable land, fresh water or fertilizers. The present review offers an objective perspective of the current knowledge surrounding the impacts of seaweeds and their derived polysaccharides on the human microbiome and the profound need for more in-depth investigations into this topic. Animal experiments and in vitro colonic-simulating trials investigating the effects of seaweed ingestion on human gut microbiota are discussed.

Effect of Carrageenans on Vegetable Jelly in Humans with Hypercholesterolemia

Changes in lipid profile constitute the main risk factor for cardiovascular diseases. Algae extracted carrageenans are long-chain polysaccharides and their ability to form gels provides for the formation of vegetable jelly. The objective was to evaluate the bioactive potential of carrageenan (E407) in the lipid profile, after ingestion of jelly. A total of 30 volunteers of both sexes, aged 20-64 years and with total cholesterol (TC) values ≥200 mg/dL, who ingested 100 mL/day of jelly for 60 days, were studied. All had two venous blood collections: before starting the jelly intake and after 60 days. At both times, TC, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and triglycerides (TG), were evaluated using commercial kits and spectrophotometer. The statistics were performed using the SPSS 25.0 software and p < 0.05 were considered statistically significant. Serum values after 60 days of jelly intake revealed a statistically significant decrease in TC levels (5.3%; p = 0.001) and LDL-C concentration (5.4%; p = 0.048) in females. The daily intake of vegetable jelly for 60 days showed a reduction in serum TC and LDL-C levels in women, allowing us to conclude that carrageenan has bioactive potential in reducing TC concentration.

Effect of carrageenans on some lipid metabolism components in vitro

The research described here focused on the effect of sulfated red algal polysaccharides (κ-, κ/β-, ι/κ-carrageenan) individually and in combination with lipopolysaccharide (LPS) on the synthesis of prostaglandin E₂ (PGE₂) and cytokines (interleukin [IL]-1β and IL-6) in whole blood model in vitro. The results demonstrated that, at high concentrations, carrageenans have substantial ability to modulate PGE₂ synthesis and stimulate IL-1β and IL-6 synthesis. A low degree of sulfate and high molecular weight were a prerequisite for the ability of carrageenans to modulate PGE₂ synthesis. Further, we investigated the ability of the carrageenans alone and in combination with casein to affect bile salt permeability through an artificial membrane imitating the gastrointestinal barrier. The least sulfated κ/β-carrageenan could retain bile salt permeation the most but less efficiently than cholestyramine. The polysaccharides did not affect pancreatic lipase activity. Our data confirm a possible mechanism of the cholesterol-reducing properties of carrageenan.

Risks and benefits of consuming edible seaweeds

Recent interest in seaweeds as a source of macronutrients, micronutrients, and bioactive components has highlighted prospective applications within the functional food and nutraceutical industries, with impetus toward the alleviation of risk factors associated with noncommunicable diseases such as obesity, type 2 diabetes, and cardiovascular disease. This narrative review summarizes the nutritional composition of edible seaweeds; evaluates the evidence regarding the health benefits of whole seaweeds, extracted bioactive components, and seaweed-based food products in humans; and assesses the potential adverse effects of edible seaweeds, including those related to ingestion of excess iodine and arsenic. If the potential functional food and nutraceutical applications of seaweeds are to be realized, more evidence from human intervention studies is needed to evaluate the nutritional benefits of seaweeds and the efficacy of their purported bioactive components. Mechanistic evidence, in particular, is imperative to substantiate health claims.

Optimization of Phlorotannins Extraction from Fucus vesiculosus and Evaluation of Their Potential to Prevent Metabolic Disorders

Phlorotannins are phloroglucinol-based phenolic compounds, occurring particularly in brown macroalgae, that have been recognized for their promising bioactive properties. In this study, the extraction of phlorotannins from Fucus vesiculosus was evaluated with particular emphasis on the influential parameters, including the solvent concentration, solvent-solid ratio, extraction temperature and extraction time, using a single-factor design followed by a Box-Behnken design. The maximum total phlorotannin content, determined using the 2,4-dimethoxybenzaldehyde (DMBA) method, corresponded to 2.92 ± 0.05 mg of phloroglucinol equivalents/g dry seaweed (mg PGE/g DS), and was achieved for extracts carried out with acetone 67% (v/v), a solvent-solid ratio of 70 mL/g and temperature at 25 °C. This crude extract, together with a semi-purified phlorotannin fraction, were further evaluated for their anti-enzymatic capacity against α-glucosidase, α-amylase and pancreatic lipase, both showing promising inhibitory effects, particularly against α-glucosidase for which a greater inhibitory effect was observed compared to the pharmaceutical drug acarbose (IC50 = 4.5 ± 0.8 and 0.82 ± 0.3 μg/mL, respectively, against 206.6 ± 25.1 μg/mL). Additionally, the ultra-high-pressure liquid chromatography coupled to mass spectrometry (UHPLC-MS) analysis carried out on the ethyl acetate fraction revealed the presence of fucols, fucophlorethols, fuhalols and several other phlorotannin derivatives. Moreover, possible new phlorotannin compounds, including fucofurodiphlorethol, fucofurotriphlorethol and fucofuropentaphlorethol, have been tentatively identified in this extract. Overall, this study provides evidence that F. vesiculosus phlorotannin-rich extracts hold potential for the management of the activity of α-glucosidase, α-amylase and pancreatic lipase, which are well known to be linked to metabolic disorders such as diabetes and obesity.

Extracts from the edible seaweed, Ascophyllum nodosum, inhibit lipase activity in vitro: contributions of phenolic and polysaccharide components

A polyphenol-rich extract (PRE) from the edible seaweed, Ascophyllum nodosum, inhibited pancreatic lipase activity in an oil-based turbidimetric assay with an IC50 of 200 μg gallic acid equivalents (GAE) perassay) [∼230 μg DW] whereas the known inhibitor, Orlistat, gave an IC50 at 0.4 μg per assay. A phlorotannin-enriched fraction (TRF) purified from the PRE was more potent with an IC50 = 60 μg GAE per assay (∼65 μg DW). When the assay was started by the addition of lipase, both Orlistat and TRF were much less effective which suggests that pre-incubation of enzyme and inhibitor improved inhibition. Based on phenol content, water extracts from Ascophyllum were more potent lipase inhibitors than PRE (IC50 ∼ 150 μg GAE per assay). However, this was equivalent to ∼580 μg DW and these extracts contained polysaccharides (e.g. alginate content = 110 μg mL-1) which may also contribute to inhibition. Indeed, a polysaccharide-enriched fraction obtained by ethanol precipitation gave an IC50 of 1000 μg DW which was equivalent to 130 μg GAE and 420 μg alginate per assay. Therefore a >3 fold increase in alginate content did not markedly improve inhibition. Re-precipitation increased alginate content and reduced polyphenol content but lipase inhibition was markedly reduced (i.e. IC50 at ∼1100 μg DW per assay, 700 μg alginate and 25 μg GAE). Purifying the polysaccharide fraction by ion exchange removed all phenolics but the IC50 increased to >2500 μg DW, equivalent to >1970 μg alginate per assay. In conclusion, polysaccharides and phlorotannins may inhibit lipase in an additive fashion, with phlorotannins apparently more effective in vitro. However, interactions between these components may be important when food products containing this edible seaweed are consumed.

Lipase inhibitory activity of Lagenaria siceraria fruit as a strategy to treat obesity

OBJECTIVE

To explore pancreatic lipase inhibitory activity under different extraction conditions in order to track the most potent extract.

METHODS

The methanolic extract and its fractions in solvents of increasing polarity, ether, chloroform, ethyl acetate, n-butanol and water, were made through cold maceration. Extracts in ethanol, ethyl acetate, acetone and chloroform were similarly prepared. Aqueous extract was prepared through hot decoction method. A reported method was used to determine lipase inhibitory activity of extracts and fractions over wide ranges of concentrations.

RESULTS

The extracts and fractions exhibited concentration dependent activity. The IC₅₀ (μg/mL) values of methanolic, ethanolic, chloroform, ethyl acetate, acetone, ethyl acetate (after washing with water) and aqueous decoction were 293.40, 266.47, 157.59, 182.12, 352.34, 257.00, and 190.00, respectively. The activity of chloroform, ethyl acetate and aqueous extracts were close to that of the drug orlistat (IC₅₀ 146 μg/mL). Out of the fractions of the methanolic extract, the chloroform fraction was most active (IC₅₀ 189.6 μg/mL). The order of inhibitory activity of the fractions was as follows: chloroform＞ether＞n-butanolic＞aqueous＞ethyl acetate. The GC/MS analysis of the most active chloroform faction showed the presence of hexadecanoic acid, methyl hexadecanoate, isopropyl palmitate, methyl 9,12-octadecadienate, and methyl 9,12,15-octadecatrienoate.

CONCLUSIONS

The study suggests that Lagenaria siceraria has potential to inhibit pancreatic lipase activity, suppressing lipid digestion and thereby diminishing entry of lipids into the body. Regular intake of aqueous decoction of the fruit may therefore be recommended for control of obesity. Fatty acids and their esters may play role as inhibitors of lipase.

Marine Algae as a Potential Source for Anti-Obesity Agents

Obesity is a major epidemic that poses a worldwide threat to human health, as it is also associated with metabolic syndrome, type 2 diabetes and cardiovascular disease. Therapeutic intervention through weight loss drugs, accompanied by diet and exercise, is one of the options for the treatment and management of obesity. However, the only approved anti-obesity drug currently available in the market is orlistat, a synthetic inhibitor of pancreatic lipase. Other anti-obesity drugs are still being evaluated at different stages of clinical trials, while some have been withdrawn due to their severe adverse effects. Thus, there is a need to look for new anti-obesity agents, especially from biological sources. Marine algae, especially seaweeds are a promising source of anti-obesity agents. Four major bioactive compounds from seaweeds which have the potential as anti-obesity agents are fucoxanthin, alginates, fucoidans and phlorotannins. The anti-obesity effects of such compounds are due to several mechanisms, which include the inhibition of lipid absorption and metabolism (e.g., fucoxanthin and fucoidans), effect on satiety feeling (e.g., alginates), and inhibition of adipocyte differentiation (e.g., fucoxanthin). Further studies, especially testing bioactive compounds in long-term human trials are required before any new anti-obesity drugs based on algal products can be developed.