Chordaria cladosiphon

Other Names

Chordaria dictyosiphonCladosiphon chordariaCladosiphon chordaria var. dictyosiphon

Synopsis

Chordaria cladosiphon (Okinawa Mozuku): A Comprehensive Reference

1. Identity, Taxonomy, and Nomenclature

1.1 Scientific Names and Taxonomic Position

Chordaria cladosiphon is a species of brown algae in the family Chordariaceae. It was formally described as Chordaria cladosiphon Kützing in 1859, published in his Tabulae phycologicae, originally placed under the name Cladosiphon. The name is currently accepted as taxonomically valid and refers to a marine species.

The genus Chordaria, established by C. Agardh in 1817, belongs to the order Ectocarpales, family Chordariaceae, within the class Phaeophyceae (brown algae), phylum Ochrophyta, infraregnum Heterokonta.

An important taxonomic clarification is warranted. The supplement industry and several patent and research documents use the designations Chordaria cladosiphon and Cladosiphon okamuranus in overlapping contexts, reflecting the complex synonymy within the Chordariaceae family. Historical taxonomic treatments have placed Chordaria cladosiphon as a synonym within the genus Sphaerotrichia Kylin, 1940, alongside other former Chordaria species. The World Register of Marine Species (WoRMS) records Chordaria dictyosiphon (Harvey) Kützing, 1859 as accepted under Chordaria cladosiphon Kützing, 1859. In commercial supplement contexts, the ingredient sold under this name is most often the fucoidan-rich extract derived from Cladosiphon okamuranus Tokida, also of the family Chordariaceae, the species that constitutes virtually all of the peer-reviewed research base reviewed here.

1.2 The Commercially Relevant Species: Cladosiphon okamuranus

Cladosiphon okamuranus Tokida is an edible seaweed classified as brown algae and is a native species of the Ryukyu Islands in Japan. It is naturally found in Okinawa, Japan, where most mozuku is farmed by locals and sold to processing factories. The main use of mozuku is as food and as a source of a sulfated polysaccharide called fucoidan, which has been studied as a cancer treatment and health supplement.

It is the commercially important seaweed within the order Chordariales, family Chordariaceae, which has about 500 species. Cladosiphon is a type of alga from which acetyl fucoidan is isolated, and it is commercially cultured, particularly around the Okinawa Islands in Japan.

1.3 Common Names and Preparations

The Japanese name for Cladosiphon okamuranus is written as モズク, 水雲, 藻付, 海蘊, or 海雲 — collectively rendered as mozuku. The seaweed is also specifically known as Okinawa mozuku to distinguish it from other mozuku-type seaweeds.

It is primarily consumed as a fresh or processed seaweed in various culinary preparations, often harvested and immediately processed into thread-like strands, which are used in soups, salads, and side dishes to add a unique slimy texture and umami flavor. A particularly common method in Okinawan cuisine involves pickling the seaweed in vinegar, creating a tangy dish eaten raw or lightly seasoned with soy sauce. This vinegar-pickled form is a staple in daily meals and can also be incorporated into stir-fries, tempura, or rice preparations.

As a dietary supplement, the ingredient is sold primarily as a standardized fucoidan extract in capsule, tablet, powder, and liquid beverage forms. An EU novel food application submitted for fucoidan extract from Cladosiphon okamuranus proposed a maximum recommended use level of 1,770 mg/day, provided in 6 capsules of 295 mg each. Fucoidan is prepared on an industrial scale from algae and used as an additive for health foods, drinks, and cosmetics in Japan.

2. Traditional and Historical Use

Okinawa mozuku has formed part of the traditional Okinawan diet since ancient times; aquaculture technologies for its cultivation began in the 1970s, and today about 20,000 tons are produced every year, with Okinawa Prefecture accounting for over 90% of production in Japan.

Since ancient times in the Okinawa region of Japan, Okinawa mozuku (Cladosiphon okamuranus) has historically been utilized as food and is a main source of dietary fiber for the native population.

In Japan, daily seaweed consumption can exceed approximately 5 g/day, and brown seaweed mozuku represents one of the most common edible seaweeds, usually consumed raw. Okinawa mozuku is exclusively cultivated and used in the traditional cuisine on the Okinawan Islands in Japan, a region that is well-known for its high prevalence of centenarians and the general healthy states of its elderly population.

Laminaria japonica (kombu), Undaria pinnatifida (wakame), Gelidium crinale (tengusa), and Cladosiphon okamuranus (mozuku) have traditionally been consumed in Japan.

The cultivation of Okinawa mozuku in Okinawa Prefecture was established by the Okinawa Prefectural Fisheries Research and Extension Center in the 1970s, and the prefecture is currently capable of providing large-scale production and a stable supply of this seaweed, accounting for more than 90% of domestic distribution in Japan.

In traditional culinary and wellness practice, mozuku has been consumed primarily as a whole food. There are no formal historical pharmacopeial monographs for Chordaria cladosiphon or Cladosiphon okamuranus as a medicinal herb in the Western or classical Chinese medical traditions. Its long-standing use has been as an everyday dietary food — particularly in soups and vinegared preparations — rather than as a formulated medicine.

3. Key Constituents and Active Compounds

3.1 Fucoidan: The Principal Bioactive Compound

Fucoidan is a sulfated polysaccharide, made up mainly of L-fucose, found in brown seaweeds. Its chemical structure is diverse and depends on maturity, species, and geographical location.

Fucoidan from Cladosiphon okamuranus is a sulfated polysaccharide with a linear backbone of 1-3-linked α-fucopyranose with 50% sulfate substitution at the 4-positions and some O-acetylated fucose residues.

Fucoidan extracted from Okinawa mozuku (OM fucoidan) has a simple structure with a backbone of α-(1→3) fucopyranose, substituted with sulfate and α-glucuronic acid at approximately 50 and 17% of its residues, respectively.

Studies report that Japanese Cladosiphon okamuranus fucoidan contains 70.13 ± 0.22 wt% fucose and 15.16 ± 1.17 wt% sulfate. Other minor monosaccharides found were D-xylose, D-galactose, D-mannose, D-glucose, D-arabinose, D-rhamnose, and D-glucuronic acid.

Linkage analysis revealed that fucopyranoside units along the backbone are linked through α-1,3-glycosidic bonds, with fucose branching at C-2 and one sulfate group at C-4 per every three fucose units.

A commercially prepared fucoidan from Cladosiphon okamuranus Tokida used in research was characterized as having an average molecular weight of 49.8 kDa, L-fucose content of 52.7%, uronic acid content of 18.0%, and sulfate ion content of 17.6%.

This fucoidan has a linear backbone of 1-3-linked α-fucopyranose with 50% sulfate substitution at the 4-positions, and some of the fucose residues are O-acetylated. This particular fucoidan is characterized by a simpler structure than that of fucoidan derived from other brown algae such as Gagome kombu and Mekabu.

3.2 Other Constituents

Nutritionally, C. okamuranus is valued for its content of iodine, essential vitamins such as C and K, and dietary fiber, while being low in calories, making it a suitable addition to health-conscious diets. The seaweed's water-soluble fiber supports digestive health, and its mineral profile, including calcium, magnesium, and iron, contributes to overall nutritional balance.

Brown seaweeds (Phaeophyceae) are known to produce different polysaccharides, namely alginates, laminarins, and fucoidans. These polysaccharides usually contain large proportions of L-fucose and sulfate, together with minor amounts of other sugars such as xylose, galactose, mannose, and glucuronic acid.

3.3 Established Mechanisms of Action

Fucoidans modulate inflammation, possess antiproliferative and anti-adhesive effects on cells, protect cells from viral infection, and also interfere with mammalian fertilization.

In the context of anti-tumor activity, fucoidan significantly inhibited the growth of peripheral blood mononuclear cells of adult T-cell leukemia (ATL) patients and HTLV-1-infected T-cell lines but not that of normal peripheral blood mononuclear cells. Fucoidan induced apoptosis of HTLV-1-infected T-cell lines mediated through downregulation of cellular inhibitor of apoptosis protein-2 and survivin, and G1 phase accumulation through the downregulation of cyclin D2, c-myc, and the hyperphosphorylated form of the retinoblastoma tumor suppressor protein.

Regarding anti-inflammatory effects, the generation of superoxide by macrophages and PMNs was stimulated by dextran sulfate, carrageenan, and Fucus fucoidan, whereas Cladosiphon fucoidan, heparin, and chondroitin did not. Dextran sulfate, carrageenan, and Fucus fucoidan also stimulated the secretion of TNF-alpha from macrophages, while Cladosiphon fucoidan did not. Thus, Cladosiphon fucoidan is a sulfated polysaccharide without inflammatory action.

For antiviral activity, fucoidan possesses activity against different viruses, such as HIV, herpes simplex virus, dengue virus, and cytomegalovirus, and its antiviral activity appears to inhibit the initial steps of infection. More specifically, Cladosiphon okamuranus-derived fucoidan directly interacts with dengue virus type 2 (DENV-2) to inhibit infection and decreases Newcastle disease virus (NDV) infectivity by blocking fusion proteins and inhibiting virus-induced syncytia formation.

Regarding gastric protection and Helicobacter pylori, fucoidan can block the attachment of H. pylori to gastric cells. An in vitro experiment confirmed that Cladosiphon fucoidan inhibited the H. pylori attachment to porcine gastric mucin at pH 2.0 and 4.0.

In immunomodulation, fucoidan from Okinawa mozuku increased immune cell proliferation, interleukin (IL)-2, macrophage phagocytosis, and serum antibodies (IgM, IgG, IgA) significantly, while IL-4, IL-5, and IgE decreased significantly, indicating that fucoidan modulated both cellular and humoral immunity.

4. Scientific Evidence by Area of Use

4.1 Immune Modulation and NK Cell Activity

Human Clinical Evidence: A randomized, double-blind, parallel-group, placebo-controlled pilot study evaluated the effects of ingesting fucoidan derived from Okinawa mozuku on natural killer (NK) cell activity in healthy adults. Subjects were randomly divided into a placebo group (n = 20; mean age 45.5 ± 7.8 years) and a fucoidan group ingesting 3.0 g/day from beverages (n = 20; mean age 47.0 ± 7.6 years); blood, biochemical, and immunological tests were performed after 12 weeks. NK cell activity was significantly enhanced at 8 weeks in the fucoidan group, compared to before ingestion (0 weeks). A significantly enhanced NK cell activity was also observed in male subjects at 8 weeks compared with the placebo group. These results confirm that Okinawa mozuku-derived fucoidan enhances NK cell activity and suggest that it is a safe food material. The study is limited by its small sample size (n = 40 total) and pilot design.

A separate prospective, open-label clinical study examined NK cells in cancer survivors. Eleven cancer survivors with a performance status of 0 or 1 participated and consumed 3 g of fucoidan for 6 months. No significant changes were observed in the mean activities of NK cells in total subjects following the ingestion of fucoidan. This study's lack of controls and small population limit interpretation.

Animal Evidence: Eight-week-old female BALB/c mice received fucoidan orally at doses of 0, 102.5, 205.0, 410.0, and 1025.0 mg/kg for six weeks. Immune cell proliferation, cytokine production, macrophage phagocytosis, and serum antibody concentration were measured. Immune cell proliferation, IL-2, macrophage phagocytosis, and serum antibodies (IgM, IgG, IgA) increased significantly, but IL-4, IL-5, and IgE decreased significantly.

Evidence Assessment: Preliminary. There is one small RCT showing positive effects on NK cell activity in healthy adults, but larger and more rigorous trials are needed.

4.2 Anticancer / Anti-Tumor Activity

In Vitro and Cell-Based Evidence: Cladosiphon okamuranus Tokida-derived fucoidan inhibited the growth of peripheral blood mononuclear cells of adult T-cell leukemia patients and caused apoptosis of HTLV-1-infected T-cell lines through a cascade of downregulations. The fucoidan exerted efficacy against mice with implanted tumors.

Limited Human/Clinical Evidence: A clinical trial was performed on fucoidan in patients with advanced colon cancer. Ikeguchi et al. reported that ingestion of 4.05 g per day of fucoidan derived from Cladosiphon okamuranus reduced the clinical toxicity indicator "fatigue" in patients receiving conventional chemotherapy. Furthermore, patients administered fucoidan tolerated more cycles of chemotherapy. A clinical trial on fucoidan in patients with different types of advanced cancers identified the responsiveness of interleukin (IL)-1β as a significant independent prognostic factor. However, NK cell activity was not affected by a four-week treatment with fucoidan derived from C. novae-caledoniae.

Adult T-cell leukemia (ATL) is caused by HTLV-1 and remains incurable. The highest endemic area of HTLV-1 carriers in Japan is located in Okinawa. Researchers extracted fucoidan from Cladosiphon okamuranus Tokida cultivated in Okinawa and examined its tumor-suppression activity against ATL. Fucoidan significantly inhibited the growth of peripheral blood mononuclear cells of ATL patients and HTLV-1-infected T-cell lines but not normal cells. Fucoidan induced apoptosis of HTLV-1-infected T-cell lines through downregulation of anti-apoptotic proteins and cell cycle regulators.

Evidence Assessment: Predominantly preclinical (cell line and animal). Limited clinical data show possible supportive roles during chemotherapy and effects on HTLV-1-associated disease, but no randomized controlled trials demonstrating anti-tumor efficacy as a primary endpoint in humans have been published.

4.3 Gastrointestinal Health — Helicobacter pylori and Gastric Protection

In Vitro and Animal Evidence: Cladosiphon fucoidan inhibited H. pylori attachment to porcine gastric mucin at pH 2.0 and 4.0. Two other sulfated polysaccharides also inhibited attachment at pH 2.0 only. In an in vivo experiment using Mongolian gerbils, H. pylori-induced gastritis and the prevalence of H. pylori-infected animals were markedly reduced by fucoidan in a dose-dependent manner at doses of 0.05 and 0.5% in the drinking water. Cladosiphon fucoidan may deserve particular attention as a safe agent that can prevent H. pylori infection and reduce the risk of associated gastric cancer.

To elucidate the anti-ulcer potential of Cladosiphon fucoidan, anti-peptic activity, bFGF-stabilizing activity, and inflammatory properties were investigated. Anti-peptic activity was observed with this and other sulfated polysaccharides such as dextran sulfate, carrageenan, and Fucus fucoidan. However, non-sulfated polysaccharides such as mannan and dextran did not exert the anti-peptic activity.

Evidence Assessment: Preclinical only for this organism's fucoidan. Well-characterized in vitro and animal models support an anti-adhesion mechanism against H. pylori, but human clinical trials on C. okamuranus fucoidan specifically for this indication have not been reported in the literature reviewed.

4.4 Antiviral Activity

Fucoidan is a sulfated polysaccharide present in the cell wall matrix of brown algae that has been demonstrated to inhibit certain enveloped viruses with low toxicity. A study evaluated the potential antiviral activity and mechanism of action of fucoidan from Cladosiphon okamuranus against Newcastle Disease Virus in the Vero cell line. Cladosiphon okamuranus-derived fucoidan directly interacts with dengue virus type 2 (DENV-2) to inhibit infection and decreases NDV infectivity by blocking fusion proteins and inhibiting virus-induced syncytia formation.

Previous reports indicate that fucoidans derived from various species inhibit SARS-CoV-2 infection by binding to the spike protein and inactivating the furin required for the cleavage of this protein.

Evidence Assessment: In vitro only. No human antiviral trials specific to C. okamuranus-derived fucoidan have been reported for viral infections in general populations.

4.5 Cardioprotection and Lipid Modulation

Animal Evidence: The cardioprotective activity of fucoidan extracted from Cladosiphon okamuranus was evaluated in isoproterenol-induced myocardial infarction in male Wistar albino rats. Isoproterenol administration produced severe myocardial damage and high lipid peroxidation. Fucoidan treatment reduced myocardial damage, reflected by improvement in creatinine phosphokinase (CPK), lactate dehydrogenase (LDH), alanine transaminase (ALT), and aspartate transaminase (AST).

Human Evidence: Twenty healthy adult volunteers received 4.05 g per day of mozuku fucoidan (isolated from Cladosiphon okamuranus) for two weeks. Blood samples showed a significant decrease in total cholesterol and low-density lipoprotein cholesterol. The concentration of chloride ions increased significantly. This was a small, short-duration, uncontrolled pilot observation.

Evidence Assessment: Preliminary. One small uncontrolled human study showed cholesterol-lowering signals; animal data support cardioprotective potential under experimentally induced cardiac injury. Larger controlled human trials are lacking.

4.6 Immunomodulation and HTLV-1-Associated Disease

Beyond the general NK cell studies discussed above, previous studies of Okinawa mozuku-derived fucoidan have reported anticoagulant, anti-inflammatory, antiviral, anti-HTLV-1, antitumor, antihepatitis, and antiulcer effects.

One clinical study examined fucoidan's effects on HTLV-1-associated neurological disease. Araya et al. found that fucoidan therapy decreased the proviral load in patients with human T-lymphotropic virus type-1-associated neurological disease. This represents a notable early human clinical signal in a specific infectious/oncological indication, though it requires replication in larger controlled trials.

Evidence Assessment: Preliminary human clinical signals in HTLV-1-related conditions, supported by robust in vitro mechanistic data. Independent replication and larger trials are needed.

4.7 Microbiota and Intestinal Immune Modulation

A study investigated in vivo effects of fucoidan extracted from Okinawa mozuku on immune responses and microbiota composition in zebrafish. Larvae and adult zebrafish were treated with Okinawa mozuku fucoidan by immersion (100 and 500 μg/mL, 3 days) and by feeding (3 weeks), respectively. The effect on immune responses in zebrafish larvae was evaluated by live imaging of neutrophils and macrophages as well as quantitative PCR of pro- and anti-inflammatory cytokine genes. Fucoidan from different algal origins has been reported to exhibit unique properties such as anti-inflammatory, anti-allergic, antitumor, or antiviral effects, and is therefore recognized as a prospective ingredient for functional foods and therapeutic agents.

Evidence Assessment: Animal/aquatic model only. No human clinical data on microbiota modification from C. okamuranus fucoidan have been published.

5. Body Systems and Health Areas of Association

Immune system: NK cell activation, modulation of cellular and humoral immunity (IL-2 upregulation, IgM/IgG/IgA increase; IL-4/IL-5/IgE decrease)
Oncology (supportive): Apoptosis induction in HTLV-1-infected cells, reduction of chemotherapy-associated fatigue (clinical, preliminary)
Gastrointestinal system: Anti-adhesion against H. pylori, anti-peptic activity, gastric mucosal protection
Cardiovascular system: Anticoagulant and antithrombotic effects, cardioprotective activity in animal models, preliminary LDL-lowering in humans
Antiviral defense: Inhibition of enveloped viral fusion, activity against dengue, NDV, and HTLV-1 (predominantly in vitro)
Intestinal microbiota: Immune modulation via gut flora (animal models)
Metabolic (lipids): Preliminary total cholesterol and LDL reduction in small human study

6. Dosage Forms and Reported Dosages

All dosages below are reported as they appear in the cited scientific literature and regulatory documents; they do not represent recommendations.

3.0 g/day as a fucoidan beverage in a 12-week double-blind RCT evaluating NK cell activity in healthy adults (n = 40).
4.05 g/day of fucoidan derived from Cladosiphon okamuranus administered to patients with advanced colon cancer receiving conventional chemotherapy.
4.05 g/day of mozuku fucoidan given to 20 healthy adult volunteers for two weeks in a safety and lipid study.
The EU novel food application for fucoidan extract from C. okamuranus proposed a maximum recommended daily dose of 1,770 mg/day, delivered as 6 capsules of 295 mg each.
This supplement regimen corresponds to a daily dosage of approximately 23.6–29.5 mg/kg body weight for an average adult weighing 60–75 kg.
In a murine immunomodulation study, fucoidan was administered orally at doses of 0, 102.5, 205.0, 410.0, and 1025.0 mg/kg for six weeks in BALB/c mice.
In a Mongolian gerbil H. pylori model, Cladosiphon fucoidan reduced gastritis in a dose-dependent manner at doses of 0.05 and 0.5% in the drinking water.

7. Safety Considerations and Interactions

7.1 Toxicology Data

The acute toxicity of varying levels of fucoidan extracted from Cladosiphon okamuranus was examined in Wistar rats after oral administration. No significant toxicological changes were induced by fucoidan at a dose of 600 mg/kg of body weight/day.

Toxicity tests showed that C. okamuranus shows no significant toxic side effects in rats at a dosage of 600 mg/kg body weight.

The consumption of 600 mg/kg of fucoidans extracted from Cladosiphon okamuranus did not cause hematological changes, but at 1200 mg/kg/day resulted in anticoagulant activity.

7.2 Anticoagulant Activity

Besides their well-known anticoagulant and antithrombotic activity, fucoidans modulate inflammation, possess antiproliferative and anti-adhesive effects on cells, and protect cells from viral infection. A potential safety issue arises from the anticoagulant activity of fucoidan from Cladosiphon okamuranus and other species. One analysis noted that the lowest oral dose inducing prolongation of clotting time in rats is more than 200-fold greater than dietary exposure. A study in humans showed that less than 1% of ingested fucoidan is absorbed into the bloodstream.

7.3 Human Clinical Safety Data

In the 12-week randomized controlled pilot study, clinically adverse events were not observed in any of the tests during the study period. Adverse events due to the test food were not observed.

Cladosiphon fucoidan is a sulfated polysaccharide without inflammatory action. These results suggest that it is a safe substance with potential for gastric protection.

7.4 Mineral Absorption

A study investigated whether addition of fucoidan (Yakult Fucoidan) prepared from Cladosiphon okamuranus Tokida to food affects the availability of divalent minerals for intestinal absorption. In a dynamic multicompartmental model of the upper gastrointestinal tract (TIM-1), fucoidan at doses of 0.033 g and 0.1 g (corresponding to approximately 1.7 and 5.0 mg/kg body weight in humans) did not significantly decrease the bioaccessibility of calcium, magnesium, iron, zinc, manganese, copper, and cobalt compared to the test meal without fucoidan.

7.5 Absorption and Bioavailability

High molecular weight fucoidan can be detected in human plasma with an absorption rate of approximately 0.6% at the intestine. Medium molecular weight fucoidan (28.8 kDa) from Cladosiphon okamuranus accumulated in mononuclear cells in the jejunal lamina propria and sinusoidal non-parenchymal cells in the liver.

7.6 Regulatory Status

An application has been submitted to include fucoidan extract from Cladosiphon okamuranus in the EU Union list of novel foods to be used in food supplements. It is not intended to be an alternative or replacement to any existing foods consumed as part of the normal diet. The EU classifies foods and supplements as "traditional" or "novel," the latter covering ingredients not widely consumed before May 1997. Fucoidan extract is generally considered a novel food in the EU unless a long history of use in specific EU countries can be demonstrated.

8. Summary of Evidence Quality

The body of published research on Chordaria cladosiphon/Cladosiphon okamuranus fucoidan is substantial at the preclinical level. Fucoidan is a promising bioactive compound with anti-inflammatory, anticoagulant, anticancer, antioxidant, antiviral, and cardioprotective properties. However, although beneficial effects of fucoidan have been well-studied and described, daily intake of fucoidan from brown seaweed is still not common in Western countries.

The majority of mechanistic research is in vitro or animal-based. Human clinical trials are limited in number, small in sample size, short in duration, and often lack robust controls. Specific areas — including NK cell modulation and HTLV-1-related disease — have preliminary human data but require replication. For most claimed benefits, the evidence level should be characterized as preliminary and primarily preclinical.

References

Health Conditions

Health conditions that Chordaria cladosiphon may help support.

No conditions available.

Body Systems

Body systems that Chordaria cladosiphon may help support.

No body systems available.