κ- and λ-Carrageenans from Marine Alga Chondrus armatus Exhibit Anticancer In Vitro Activity in Human Gastrointestinal Cancers Models.

The carrageenans isolated from red algae demonstrated a variety of activities from antiviral and immunomodulatory to antitumor. The diverse structure and sulfation profile of carrageenans provide a great landscape for drug development. In this study, we isolated, purified and structurally characterized κo- and λo- oligosaccharides from the marine algae Chondrus armatus. We further examined the tumor suppressive activity of both carrageenans in gastrointestinal cancer models. Thus, using MTT assay, we could demonstrate a pronounced antiproliferative effect of the carrageenans in KYSE-30 and FLO-1 as well as HCT-116 and RKO cell lines with IC50 184~405 µg/mL, while both compounds were less active in non-cancer epithelial cells RPE-1. This effect was stipulated by the inhibition of cell cycle progression in the cancer cells. Specifically, flow cytometry revealed an S phase delay in FLO-1 and HCT-116 cells under κo-carrageenan treatment, while KYSE-30 demonstrated a pronounced G2/M cell cycle delay. In line with this, western blotting revealed a reduction of cell cycle markers CDK2 and E2F2. Interestingly, κo-carrageenan inhibited cell cycle progression of RKO cells in G1 phase. Finally, isolated κo- and λo- carrageenans induced apoptosis on adenocarcinomas, specifically with high apoptosis induction in RKO cells. Overall, our data underline the potential of κo- and λo- carrageenans for colon and esophageal carcinoma drug development.

Physicochemical Evaluation of Personal Care Products Developed with Chondrus crispus Fractions Processed by Ecofriendly Methodologies.

Novel personal care products are necessary to cope with the growing market demand for sustainable green products. In this context, this work deals with the formulation and fundamental physicochemical and rheological characterization of different natural personal care products using bioactive fractions from Chondrus crispus red macroalgae extracted under optimized green conditions. Body milks, body oils and shampoos were supplemented with soluble extracts with antioxidant features recovered after hydrothermal (200 °C) and microwave (170 °C)- and ultrasound (80 °C)-assisted extraction of the red macroalgae used as raw material. Formulated products were also compared with those prepared using (±)-α-tocopherol and butylhydroxytoluene standards. Body scrubs were formulated with the remaining solids (<2.25%) after microwave hydrodiffusion and gravidity treatment of the macroalgae. Results indicated that selected extracts provided personal care products with similar or even better physicochemical, color and viscous features than those supplemented with (±)-α-tocopherol or butylhydroxytoluene commercial antioxidants. Rheological profiles indicated that it is possible to develop personal care products with adequate viscous behavior (102−105 mPa s, at 1 s−1), comparable with their synthetic counterparts. To conclude, the addition of antioxidant extracts led to lower apparent viscosity values suggesting an advantage from the skin applicability point of view, jointly with the absence of both the hysteresis phenomenon and water syneresis of the proposed formulations.

Efficient extraction of carrageenans from Chondrus crispus for the green synthesis of gold nanoparticles and formulation of printable hydrogels.

The integral utilization of sustainable resources with versatile, efficient and cleaner processes is encouraged. Hydrothermal treatment with subcritical water is a chemical free, tunable and rapid technology providing enhanced yield compared to conventional extraction and was explored for the benign by design extraction and depolymerization of carrageenan from Chondrus crispus. Up to 90% of the seaweed was solubilized operating under nonisothermal regime during heating up to 200 °C and 75.5% crude carrageenan yield was attained at 140 °C. Crude carrageenan could not be precipitated by ethanol from the extracts produced at 180 °C and higher temperatures, but ultrafiltration (100 kDa) of the extract obtained at 160 °C provided comparable recovery yields and similar rheological features to those of the ethanol precipitated product. Operation at 140 °C was preferred based on the higher recovery yield of the biopolymer and the whole extract was suitable for the green synthesis of polycrystalline decahedral quasi-spherical gold nanoparticles with a mean size distribution of 8.4 nm and Z potential value of -40.2 mV. Alternatively, the crude carrageen fraction was used for the formulation of printable biopolymer based gels with suitable mechanical properties, including a relevant gel strength enhancement (about 10-fold) when compared with conventional procedures.

Comparative evaluation of physicochemical profile and bioactive properties of red edible seaweed Chondrus crispus subjected to different drying methods.

Dehydration of the edible seaweed Chondrus crispus was performed by freeze-drying, conventional oven-drying and emerging microwave hydrodiffusion and gravity (MHG). In this work, the drying kinetics and modelling, estimating specific energy consumption and environmental impact of distinct processes were tested. Color and microstructural features of the dried macroalgae were also evaluated, as well as their nutritive characterization, chemical profile and bioactive potential (antioxidant and antimicrobial activities). Moreover, collected liquid phases from both the defrosted and MHG treated samples were also characterized. All methodologies provided solid phases with an adequate final moisture content. MHG significantly reduced the needed time, specific energy consumption and environmental impact, providing C. crispus with intermediate color and histological structure characteristics. Overall, this trend was also defined to tested chemical parameters and bioactivities. MHG provided aqueous extracts with potential bioactive compounds from this red alga, increasing the efficiency of this drying method.

Chondrus crispus treated with ultrasound as a polysaccharides source with improved antitumoral potential.

Ultrasound-assisted extraction was used to recover gelling biopolymers and antioxidant compounds from Chondrus crispus with improved biological potential. The optimal processing conditions were evaluated using a Box-Behnken design, and the impact on the biological and thermo-rheological properties of the carrageenan fraction and on the bioactive features of the soluble extracts were studied. The optimum extraction parameters were defined by extraction time of ~34.7 min; solid liquid ratio of ~2.1 g/100 g and ultrasound amplitude of ~79.0% with a maximum power of 1130 W. The dependent variables exhibited maximum carrageenan yields (44.3%) and viscoelastic modulus (925.9 Pa) with the lowest gelling temperatures (38.7 °C) as well as maximum content of the extract in protein (22.4 mg/g), gallic acid (13.4 mg/g) and Trolox equivalents antioxidant capacity (182.4 mg TEAC/g). Tested hybrid carrageenans exhibited promising biological activities (% of growth inhibition around 91% for four human cancer cellular lines: A549; A2780; HeLa 229; HT-29).

Seaweeds rehydration and boiling: Impact on iodine, sodium, potassium, selenium, and total arsenic contents and health benefits for consumption.

Considering the importance of seaweeds for the development of sustainable and innovative food products, this study aimed to characterize the impact of hydrothermal processing on iodine, sodium, potassium, selenium, and arsenic concentrations of four seaweed species (S. latissima, L. digitata, U. pinnatifida, and C. crispus) and on the associated health risks-benefits for consumers. These elements revealed a common pattern for leachable fractions of iodine, total arsenic, and selenium: L. digitata ≥ S. latissima > C. crispus > U. pinnatifida after rehydration and boiling during different periods. The behavior for sodium was: S. latissima > L. digitata > C. crispus > U. pinnatifida, and for potassium: U. pinnatifida > L. digitata > S. latissima > C. crispus. Generally, the species that attained more significant losses were S. latissima and L. digitata. A health-relevant sodium/potassium ratio below 0.7 was found for all species except for U. pinnatifida. In some species, the risk-benefit analysis revealed that high iodine and arsenic levels might promote risks for consumption, even after 20 min boiling, but 5 g of processed U. pinnatifida could contribute to adequate iodine, sodium, potassium, and selenium intakes for all population groups. Standardized processing treatments of seaweeds can open new opportunities for the sector.

Consumer acceptability and chemical composition of whole-wheat breads incorporated with brown seaweed (Ascophyllum nodosum) or red seaweed (Chondrus crispus).

BACKGROUND: Seaweeds have been eaten in the diets of coastal cultures for centuries; however, consumption of seaweeds has been limited in Western diets owing to undesirable sensory characteristics and lack of familiarity. Apart from healthful bioactive metabolites, seaweeds are good sources of fibre and minerals. They are nearly a complete protein and have a low fat content (mainly mono- or polyunsaturated). The objectives were (i) to investigate if the addition of brown seaweed, Ascophyllum nodosum, or red seaweed, Chondrus crispus, altered the chemical composition and sensory properties of whole-wheat bread; and (ii) to determine what percentage the addition of brown or red seaweed to whole-wheat bread is acceptable to consumers. The two seaweeds were incorporated into separate batches of whole-wheat bread by percentage weight flour at 0% (control), 2%, 4%, 6%, and 8%. RESULTS: The products containing the highest amounts of A. nodosum and C. crispus had the highest ash and total dietary fibre. A. nodosum and C. crispus breads were acceptable at 4% and 2% levels respectively. The attributes of no aftertaste, soft, and chewy drove consumer liking of the whole-wheat bread, whereas attributes dry, dense, strong aftertaste, and saltiness detracted from liking. CONCLUSION: This project's significance is to demonstrate the acceptability of seaweed in a Western population, which may lay the groundwork to encourage and promote the consumption of seaweed or to exemplify seaweed incorporation into foodstuffs. © 2020 Society of Chemical Industry.

Immunological effects of Chondrus armatus carrageenans and their low molecular weight degradation products.

Ability of high molecular weight (HMW) κ- and λ-carrageenans of the red marine algae Chondrus armatus and their low molecular weight degradation products (LMWDPs) (0.7-20 and 10-170 kDa respectively) to influence functional properties (motility and phagocytosis) of murine peritoneal macrophages was assessed in this study as an in vitro and a weeklong feeding experiment. We demonstrated that, with an exception of one, all carrageenan samples at 100 µg/ml increased cellular motility and dose-dependently decreased phagocytic activity; LMWDPs of λ-carrageenan suppressed motility and had no effect on phagocytosis. Oral administration of all the carrageenan samples at 100 µg/kg/day for 7 days to mice had no effect on their clinical appearance, body weight, weight of their liver, spleen or thymus or development of noticeable changes to their inner organs. All samples induced a shift of the cell composition of the peritoneal cavity towards macrophages. Consumption of LMWDPs of κ-carrageenan resulted in development of leukopenia, however, no changes to relative WBC count were introduced by either of the samples. All samples decreased murine peritoneal macrophages phagocytic activity, with λ-samples possessing higher efficacy than their κ-counterparts; all LMWDPs stimulated peritoneal macrophages motility, with κ-samples possessing higher efficacy than their λ-counterparts In conclusion, we have shown that κ- and λ-carrageenans of the C. armatus and their LMWDPs suppress phagocytotic activity of peritoneal macrophages under both in vitro and in vivo conditions. This allows them to be viewed as pharmacologically active substances andpropagates the need for their further investigation as such.

In vitro antitumor and immunotropic activity of carrageenans from red algae Chondrus armatus and their low-molecular weight degradation products.

Antitumor and immunotropic effects of κ-, λ-carrageenan from red marine algae Chondrus armatus and their low-molecular weight (LMW) degradation products were explored. Effects on human esophageal cancer cell lines KYSE30 and FLO1 viability and ability to induce production of pro- and anti-inflammatory cytokines by human monocytes was assessed. All polysaccharides demonstrated antimetabolic and cytostatic activity towards cancer lines, with high-molecular weight carrageenans possessing higher antimetabolic and lower cytostatic activity than their LMW degradation products. All carrageenans induced monocytes to produce pro-inflammatory cytokines IL1ß, IL6, IL18, and TNFα. However, secretion of anti-inflammatory cytokine IL10 was induced only by LMW λ-carrageenan, which exhibited the highest cytokine production inducing efficacy overall. We demonstrate that LMW carrageenan degradation products not only retain biological activity of their precursors, but also increase their efficacy in type-dependent manner, allowing for their future development for pharmacological practice.

An insight into methylene blue adsorption characteristics onto functionalized alginate bio-polymer gel beads with λ-carrageenan-calcium phosphate, carboxymethyl cellulose, and celite 545.

Herein, λ-carrageenan-calcium phosphate (λ-Carr-Cp), carboxymethylcellulose (CMC) and celite 545 (Ce545) were used to functionalize sodium alginate bio-polymer (SAB). The water content in the wet beads was about 98%. Fourier Transform Infra-Red (FT-IR) showed that SAB@λ-Carr-Cp, SAB@CMC, and SAB@Ce545 could interact through intermolecular hydrogen and electrostatic interactions. Scanning Electron Microscopy (SEM) revealed that the morphology of the functionalized beads had a porous sheet structure. Energy Dispersive X-Ray (EDX) depicted that the peak intensity of the carbon element became more intense in the case of organic modification. The appearance of mineral elements characteristics of Ce545 (Si, Al) and Cp (P) proved the incorporation of these inorganic reagents into the alginate matrix. The data from batch adsorption experiments indicated that the adsorption of methylene blue (MB) depended on pH, time, temperature, and dye concentration. At equilibrium, the adsorption capacities followed the order: SAB@Ce545 (7.5 mg g-1 wet) > SAB@λ-carr-Cp (6.8 mg g-1 wet) > SAB@CMC (6.5 mg g-1 wet) > SAB (5.77 mg g-1 wet). Kinetic data agreed with pseudo second-order suggesting chemi-sorption mechanism. The equilibrium data fitted for Freundlich. In summary, this provided assembly strategy could offer a new research opportunity for developing functionalized biopolymers with new functions and potential applications.

Impact of a new carrageenan-based vaginal microbicide in a female population with genital HPV-infection: first experimental results.

OBJECTIVE: The objective of this study was to assess safety, satisfaction, and anti-viral effect of a new carrageenan-based vaginal microbicide in a population of fertile female patients with genital human papillomavirus (HPV) infection. PATIENTS AND METHODS: Forty healthy and sexually active women aged 18-45 years with genital HPV infection were enrolled. Each subject was treated with a gel formulated with 0.02% carrageenan and Propionibacterium extract (CGP) (Carvir, Depofarma SpA, Mogliano Veneto, Treviso, Italy). The subjects were evaluated at baseline, after the I cycle of therapy and after the II cycle. At final status, treatment acceptability and satisfaction were evaluated using a 5-point Likert scale. Furthermore, the rate of HPV genital infection clearance at final follow-up was evaluated. These data were compared with the HPV genital infection clearance rate in a control group of patients not subjected to any therapy. RESULTS: Overall, 68 HPV infections were detected at baseline, among 40 subjects enrolled. The HPV 16 genotype was the most frequent (12%) followed by HPV 18 (10%), and HPV 53 (9%). At the end of the study, 22 (55%) patients were very satisfied, 14 (35%) were satisfied, 3 (7.5%) were uncertain, and only 1 (2.5%) was dissatisfied, with 0 very dissatisfied. Only 2 patients complained of a local adverse event. Analysing infection clearance at the end of the study, 60% of patients became HPV negative. Among these, 13 cases were high-risk HPV infection. There were 16 patients with persistent infection ("non-responders"). No patient developed a "de novo" genital lesion. After controlling for age, the intervention had an adjusted OR of 4.9 (95% CI 1.6-15.1) to clear HPV. CONCLUSIONS: The results of this work suggest that Carvir vulvovaginal microbicide gel is safe and well-tolerated. Furthermore, this experience supports the hypothesis that CG has a role in accelerating the normal clearance of genital HPV infection in women with a positive HPV-DNA test.

Liposomal Form of the Echinochrome-Carrageenan Complex.

Inclusion of drugs in liposomes offers the potential for localized and sustained delivery to mucosal surfaces. The inclusion of the carrageenan matrix with echinochrome A ((Ech)-the active substance of the drug Histochrome) in liposomes was studied. According to the spectral characteristics, Ech was not oxidized and retained stability after encapsulation in the liposomes and the lyophilization process. Loading the liposomes with negatively charged polysaccharide results in the increase in the zeta potential to more negative values (from -14.6 to -24.4 mV), that together with an increasing in the sizes of liposomes (from 125.6 ± 2.5 nm to 159.3 ± 5.8 nm) propose of the formation of the polymer coating on liposomes. The interactions of liposomes with porcine stomach mucin was determined by the DLS and SEM methods. The changes in the zeta-potential and size of the mucin particles were observed as the result of the interaction of liposomes with mucin. To evaluate the mucoadhesive properties of liposomes and the penetration of Ech in the mucosa, a fresh-frozen inner surface of the small intestine of a pig as a model of mucous tissue was used. Polysaccharide-coated liposomes exhibit very good mucoadhesive properties -50% of Ech remains on the mucosa.

Assessment of the effects of sulfated polysaccharides extracted from the red seaweed Irish moss Chondrus crispus on the immune-stimulant activity in mussels Mytilus spp.

Seaweeds contain a number of health enhancing and antimicrobial bioactive compounds including sulfated polysaccharides (SP). In the present study, SP extracted from a European red seaweed Irish moss Chondrus crispus was chemically analyzed, SP content extracted and the immune-response effect on wild Irish mussels Mytilus spp. investigated for the first time. A high percent yield of SP was extracted from C. crispus and the immune-stimulant activity of SP was assessed in a laboratory trial with mussels exposed to three different treatments of low (10 µg mL-1), medium (20 µg mL-1) and high (50 µg mL-1) SP dose concentrations and a control mussel group with no exposure to SP. An initial mussel sample was processed prior to the trial commencing and mussels were subsequently sampled on Days 1, 2, 3, 4, 7, and 10 post SP exposure. Both cell, humoral and immune related gene responses including haemocyte cell viability, haemocyte counts, lysozyme activity and expression of immune related genes (defensin, mytimycin and lysozyme mRNA) were assessed. No mussel mortalities were observed in either the treated or non-treated groups. Mussels exposed with SP showed an increase in haemocyte cell viability and the total number of haemocytes compared to control mussels. Lysozyme activity was also higher in treated mussels. Additionally, up-regulated expression of defensin, mytimycin and lysozyme mRNA was observed in SP treated mussels shortly after exposure (on Days 1, 2, and 3) to SP. These results indicate that a high quality yield of SP can be readily extracted from C. crispus and more importantly based on the animal model used in this study, SP extracted from C. crispus can rapidly induce health enhancing activities in Mytilus spp. at a cellular, humoral and molecular level and with a prolonged effect up to ten days post treatment.

Lectin-carbohydrate complex evaluation by chemiluminescence.

In order to characterize the affinity between specific carbohydrate-binding proteins such as lectins, a model is proposed to study these interactions using a polysaccharide membrane to simulate such adsorption. Here, lectin-carbohydrate interactions were chemiluminescently investigated using lectins conjugated to acridinium ester (AE) and polysaccharides composed of their respective specific carbohydrates. The lectin-AE conjugates were incubated with discs (0.0314-0.6358 cm2) of phytagel, chitosan and carrageenan. The complex formation chemiluminescently detected followed the Langmuir isotherm from which constants were estimated. The association constant (Ka) and maximum binding sites on the membranes were 2.4 × 10-7 M-1 ±â€¯0.8 × 10-7 M-1 and 1.3 × 10-3 mol. mg-1 ± 0.3 × 10-3 mol. mg-1 (Con A); 0.9 × 10-6 M-1 ±â€¯0.4 × 10-6 M-1 and 0.021 × 10-3 mol. mg-1 ± 0.003 × 10-3 mol. mg-1 (WGA) and 2.0 × 10-6 M-1 ±â€¯0.9 × 10-6 M-1 and 0.069 × 10-3 mol. mg-1 ± 0.010 × 10-3 mol. mg-1 (PNA). The proposed model might be useful to study binding affinity and estimate the amount of binding not limited by the sugar content in the membrane.

Seasonal acclimatization of thallus proline contents of Mastocarpus stellatus and Chondrus crispus: intertidal rhodophytes that differ in freezing tolerance.

Mastocarpus stellatus and Chondrus crispus often co-occur in the lower intertidal of Northern Atlantic rocky shorelines. At our field site along the Maine coast (USA), Mastocarpus stellatus thalli possessed greater contents of proline when compared with thalli of Chondrus crispus. In addition, M. stellatus thalli acclimated to colder growth conditions in winter/early spring by increasing proline content several fold; no seasonal acclimation in proline content was observed in C. crispus. Proline accumulates in the tissues of a broad diversity of freezing-tolerant organisms and is among the most common cryoprotectant molecules. Thus, our observations provide a basis for the previously well-documented greater freezing tolerance of Mastocarpus stellatus when compared with Chondrus crispus.

Cytoprotective Effects of the Red Marine Alga Chondrus canaliculatus Against Maneb-Induced Hematotoxicity and Bone Oxidative Damages in Adult Rats.

The current study aimed at evaluating the ability of a mineral and antioxidant-rich extract from Chondrus canaliculatus to improve maneb (MB)-induced toxicity in adult rat. The animals were divided into four groups: group 1 used as a control group, group 2 received MB, group 3 received MB + C. canaliculatus extract, and group 4 received only the algal extract. MB, a Mn-containing ethylene-bis-dithiocarbamate fungicide, induced oxidative stress damages, mineral perturbations in the plasma, urine, and bone, and genotoxicity in rats. Hematological analysis revealed in the MB-treated group a disruption in the number of red blood cells, platelets, and white blood cells associated with a striking genotoxicity. Interestingly, a significant increase in malondialdehyde and advanced oxidation protein product levels in erythrocytes and bones were found. On the other hand, an impairment of the antioxidant status in both tissues was occurred. Along, our results revealed that MB injection caused a striking drop and disruption in bone's mineral rates, especially calcium and phosphorus. These biochemical results were in accordance with the histological and molecular changes. However, co-treatment with C. canaliculatus extract showed, for the first time, that this alga was effective against MB-induced hematotoxicity, genotoxicity, and oxidative stress in the blood and bone and maintained osteomineral metabolism and bone histo-architecture. Such observations might be explained by the strong in vitro antioxidant and antibacterial activities exhibited by the alga, as well as by its high levels in several minerals: calcium, phosphorus, sodium, potassium, magnesium, iron, and zinc.

Hexose Oxidase-Mediated Hydrogen Peroxide as a Mechanism for the Antibacterial Activity in the Red Seaweed Ptilophora subcostata.

Marine algae have unique defense strategies against microbial infection. However, their mechanisms of immunity remain to be elucidated and little is known about the similarity of the immune systems of marine algae and terrestrial higher plants. Here, we suggest a possible mechanism underlying algal immunity, which involves hexose oxidase (HOX)-dependent production of hydrogen peroxide (H2O2). We examined crude extracts from five different red algal species for their ability to prevent bacterial growth. The extract from one of these algae, Ptilophora subcostata, was particularly active and prevented the growth of gram-positive and -negative bacteria, which was completely inhibited by treatment with catalase. The extract did not affect the growth of either a yeast or a filamentous fungus. We partially purified from P. subcostata an enzyme involved in its antibacterial activity, which shared 50% homology with the HOX of red seaweed Chondrus crispus. In-gel carbohydrate oxidase assays revealed that P. subcostata extract had the ability to produce H2O2 in a hexose-dependent manner and this activity was highest in the presence of galactose. In addition, Bacillus subtilis growth was strongly suppressed near P. subcostata algal fronds on GYP agar plates. These results suggest that HOX plays a role in P. subcostata resistance to bacterial attack by mediating H2O2 production in the marine environment.

Phase diagrams of hybrid carrageenans extracted from Ahnfeltiopsis devoniensis and Chondrus crispus.

NaCl and KCl phase diagrams of two kappa/iota-hybrid carrageenans (KI) are established, and the rheological properties of obtained solutions and gels are reported. KI were extracted from Ahnfeltiopsis devoniensis and Chondrus crispus seaweeds and showed different chemical composition, 48 mol% of kappa carrageenan (K) and 52 mol% of iota carrageenan (I), and 78 mol% of K and 22 mol% of I, respectively. Phase diagrams are systematically compared those of blends of commercial K and I (K+I) showing equivalent chemical compositions. Results confirm that KI clearly differ from mixtures of K and I. K+I form gels at lower polysaccharide concentration and ionic strength, and exhibit gel separation from a liquid phase when large amount (>0.1 mol/L) of KCl is used. In contrast, no syneresis was found in KI gels formed under similar conditions. Both KI and K+I gels are strain hardening, and show a concentration scaling of the elasticity with exponents ranging from 1.1 to 3.2 depending on the type of salt and ionic strength. The strain at break of KI gels does not show salt specificity and is similar to the strain at break of K+I gels in KCl under similar salt and polysaccharide concentrations. K+I gels in NaCl are more fragile than in KCl, thus showing salt specificity.

A Cultivated Form of a Red Seaweed (Chondrus crispus), Suppresses ß-Amyloid-Induced Paralysis in Caenorhabditis elegans.

We report here the protective effects of a methanol extract from a cultivated strain of the red seaweed, Chondrus crispus, against ß-amyloid-induced toxicity, in a transgenic Caenorhabditis elegans, expressing human Aß1-42 gene. The methanol extract of C. crispus (CCE), delayed ß-amyloid-induced paralysis, whereas the water extract (CCW) was not effective. The CCE treatment did not affect the transcript abundance of amy1; however, Western blot analysis revealed a significant decrease of Aß species, as compared to untreated worms. The transcript abundance of stress response genes; sod3, hsp16.2 and skn1 increased in CCE-treated worms. Bioassay guided fractionation of the CCE yielded a fraction enriched in monogalactosyl diacylglycerols (MGDG) that significantly delayed the onset of ß-amyloid-induced paralysis. Taken together, these results suggested that the cultivated strain of C. crispus, whilst providing dietary nutritional value, may also have significant protective effects against ß-amyloid-induced toxicity in C. elegans, partly through reduced ß-amyloid species, up-regulation of stress induced genes and reduced accumulation of reactive oxygen species (ROS).

Prebiotic effects of diet supplemented with the cultivated red seaweed Chondrus crispus or with fructo-oligo-saccharide on host immunity, colonic microbiota and gut microbial metabolites.

BACKGROUND: Gastrointestinal microbial communities are diverse and are composed of both beneficial and pathogenic groups. Prebiotics, such as digestion-resistant fibers, influence the composition of gut microbiota, and can contribute to the improvement of host health. The red seaweed Chondrus crispus is rich in dietary fiber and oligosaccharides, however its prebiotic potential has not been studied to date. METHODS: Prebiotic effects were investigated with weaning rats fed a cultivated C. crispus-supplemented diet. Comparison standards included a fructo-oligo-saccharide (FOS) diet and a basal diet. The colonic microbiome was profiled with a 16S rRNA sequencing-based Phylochip array. Concentrations of short chain fatty acids (SCFAs) in the feacal samples were determined by gas chromatography with a flame ionization detector (GC-FID) analysis. Immunoglobulin levels in the blood plasma were analyzed with an enzyme-linked immunosorbent assay (ELISA). Histo-morphological parameters of the proximal colon tissue were characterized by hematoxylin and eosin (H&E) staining. RESULTS: Phylochip array analysis indicated differing microbiome composition among the diet-supplemented and the control groups, with the C. crispus group (2.5% supplementation) showing larger separation from the control than other treatment groups. In the 2.5% C. crispus group, the population of beneficial bacteria such as Bifidobacterium breve increased (4.9-fold, p=0.001), and the abundance of pathogenic species such as Clostridium septicum and Streptococcus pneumonia decreased. Higher concentrations of short chain fatty acids (i.e., gut microbial metabolites), including acetic, propionic and butyric acids, were found in faecal samples of the C. crispus-fed rats. Furthermore, both C. crispus and FOS supplemented rats showed significant improvements in proximal colon histo-morphology. Higher faecal moisture was noted in the 2.5% C. crispus group, and elevated plasma immunoglobulin (IgA and IgG) levels were observed in the 0.5% C. crispus group, as compared to the basal feed group. CONCLUSIONS: The results suggest multiple prebiotic effects, such as influencing the composition of gut microbial communities, improvement of gut health and immune modulation in rats supplemented with cultivated C. crispus.