Cladosiphon Okamuranus Research Articles

Incorporation of Silver into Sulfate Groups Enhances Antimicrobial and Antiviral Effects of Fucoidan

The COVID-19 pandemic has significantly impacted our daily lives. Routine infection-control measures present an effective preventive strategy for a new infectious disease outbreak. Fucoidan, a fucose-rich sulfated polysaccharide found in brown algae, exhibits antiviral activity. Moreover, fucoidan exerts an antimicrobial effect; however, it requires considerably higher concentrations than those needed for its antiviral effect. In this study, we aimed to enhance the antimicrobial activity of fucoidan and prepared a fucoidan silver salt (Ag-Fuc) by incorporating silver ions into the sulfate groups of Yakult Fucoidan derived from Cladosiphon okamuranus Tokida. The fucoidan exhibited a weak inhibitory effect on Escherichia coli growth at significantly higher concentrations, whereas Ag-Fuc inhibited the growth of E. coli and Staphylococcus epidermidis at concentrations comparable to those required for its antiviral effects. Moreover, Ag-Fuc inhibited the growth of Cladosporium cladosporioides. Infections of human cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus were more effectively inhibited by lower concentrations of Ag-Fuc compared with fucoidan. Overall, silver ions added to the sulfate groups induced strong antimicrobial activity and enhanced the antiviral effect of fucoidan. We suggest a wide application of Ag-Fuc as a routine preventive material to avoid new infectious disease pandemics.

Refined linkage analysis of the sulphated marine polysaccharide fucoidan of Cladosiphon okamuranus with a focus on fucose

Methylation followed by depolymerization and gas chromatography (GC) is an effective methodology for the linkage analysis of polysaccharides, including fucoidan, a sulphated algal polysaccharide. However, this sample material demands attention to experimental details to prevent aberrations in the analytical result. The use of deficient bases for methylation, the presence of water, analyte degradation during hydrolysis, and coelution of the target analytes during gas chromatography create doubts about published results. We therefore investigated critical parameters of the method and carefully optimized the steps of the protocol to ensure the integrity of the results for the fucose monomers.Fucoidan from Cladosiphon okamuranus was used as reference sample to determine the glycosidic bonds, and sulphate positions in the monomer. Fucoidan in protonated form was methylated in a strictly water-free environment using lithium dimsyl as base and methyl iodide for methylation. The methylated polymer was isolated by solid phase extraction, which was crucial to recover also the highly sulfated fraction. Hydrolysis was conducted with trifluoroacetic acid. To separate all target analytes in GC-FID/MS, a stationary phase with high cyanopropyl content (HP-88) was required, as the commonly employed phenyl siloxane phases result in co-elution, which distorts the result severely.

Issue Information

Photographs of Cladosiphon okamuranus and the cultivation nets during the cultivating period in Okinawa. Center: Thalli of C. okamuranus cultivated in 8 different places in Okinawa Prefecture, Japan. Although morphologies of algae appear to be similar during sample collection, detail observation revealed some variations among them in size and level of branching. Cell wall structure of these thalli is reported by Awanthi et al. in this issue. image

Fucoidan from Cladosiphon okamuranus enhances antioxidant activity and prevents reproductive dysfunction in polystyrene microplastic-induced male rats

Plastic pollution, including microplastic, has emerged as a severe environmental and public health problem. The health risks, especially in the case of reproductive damage caused by polystyrene microplastic (PS-MP) exposure, are emerging problems that need to be solved. This study aimed to investigate the effects of fucoidan extracted from Cladosiphon okamuranus on the polystyrene microplastic-induced oxidative stress of the Leydig (LC540) cells and reproductive damage in male rats. The oxidative stress of the LC540 cells and reproductive damage in the rats were induced by PS-MP. The fucoidan treatment reduces nitric oxide (NO) and reactive oxygen species generation in the LC540 cells. In the animal study, fucoidan treatment enhanced enzymatic antioxidant activities (glutathione peroxidase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione reductase) and reduced malondialdehyde and nitric oxide production. Fucoidan supplementation also downregulates tumor necrosis factor-alpha, interleukin-6, and caspase-3 expression. Additionally, fucoidan upregulates testosterone levels, prevents the reduction of epithelium thickness, and reduces the area of the seminiferous tubule lumen. According to these conditions, fucoidan from Cladosiphon okamuranus prevents reproductive damage by downregulating oxidative stress and pro-inflammatory cytokines. Therefore, fucoidan can be used as a source of food supplements or functional food ingredients for reproductive or testicular damage management.

The Cell Wall Characterization of Brown Alga Cladosiphon okamuranus during Growth.

The present study provides new insights into the growth of the brown algal cell wall by showing that cell wall polysaccharides play an important role in the process of growth, considering the physicochemical characteristic of young and old Cladosiphon okamuranus. To determine its structural variation in detail, the cell wall was sequentially fractionated into five fractions: hot water (HW), ammonium oxalate, hemicellulose-I (HC-I), HC-II, and cellulose, and analyzed physicochemically. Results showed that almost 80% of the total recovery cell wall from both young and old thalli was HW, and HC-I contained mainly fucoidan composed of Fucose, Glucuronic acid, and sulfate in molar ratios of 1.0:0.3:0.6~0.7 and 1.0:0.3:0.2~0.3, respectively. Fucoidan in HW was a highly sulfated matrix polysaccharide abundance in young thalli, while fucoidan in HC-I was rich in old thalli and functions as hemicellulose in land plants, crosslinking with cellulose and strengthening the cell wall. We found that HW and HC-I were particularly involved in the growth and strength of old thalli appeared to be due to the deposition of HC-I and the reduction in water content during the growth process.

Enzymatic characterization of a mannuronan C5-epimerase from the subtropical brown alga Cladosiphon okamuranus

Enzymatic characterization of a mannuronan C5-epimerase from the subtropical brown alga Cladosiphon okamuranus

Characterization of cell wall polysaccharide from Cladosiphon okamuranus cultivated in different locations

SUMMARYCladosiphon okamuranus is an excellent source of fucoidan among any brown algae spp. However, the structure of polysaccharide varies significantly depending on the species, harvesting season and geographical location. To understand how geographic location affects the structure of cell wall polysaccharide, C. okamuranus cultivated in eight places (Bise, Katsuren, Yonashiro, Shikiya, Karimata, Nishihara, Hisamatsu and Ishigaki) in Ryukyu archipelago were collected during the peak harvesting time and the cell wall polysaccharide was analyzed physiochemically. The cell wall was sequentially fractionated into five fractions and its 80% was consisted of hot water fraction (HW) (60–70%) and hemicellulose‐I fraction (HC‐I) (15–20%), which mainly contained fucoidan composed of fucose (Fuc), glucuronic acid (GlcA) and sulfate (SO3−). Although the chemical composition and molecular weight of fucoidan in HW was slightly different at different places, the composition of Fuc, GlcA and SO3− was constant in the molar ratio of 1.0:0.5:0.7–1.0 respectively, suggesting that relatively similar structural fucoidan from C. okamuranus can be obtained from any geographical location in Okinawa Prefecture during peak time. However, considerable variation in the sugar composition in HC‐I was observed, despite the uniform molecular weight and SO3−. Particularly, HC‐I from Bise, where is the northern part of Okinawa Island, is composed of significantly higher amounts of Glc, Gal, Man, Xyl and morphologically thicker lateral branches compared to algae from the other parts of the island.

Elucidation of regulatory mechanisms in the activation of dendritic cells by combined stimuli with PRR ligands and sulfated polysaccharide fucoidan

Abstract Fucoidan, a series of natural high-molecular weight sulfated polysaccharides derived from brown algae, has been reported to have various physiological effects such as antitumor, antiviral, and immunomodulatory activities. In a previous study, we demonstrated that fucoidan from Cladosiphon okamuranus (Okinawamozuku) was effectively activate murine macrophage-like cell line RAW264 in synergistic action with dectin-1-stimulating beta-glucan from Saccharomyces cerevisiae. In this study, we further examined their synergistic mode of action of Okinawamozuku-derived fucoidan in cooperate with pathogen stimulation in terms of dendritic cell activation. After myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC) were differentiated by culturing bone marrow cells isolated from C57BL/6J mice with Flt3 ligand, cytokine production upon stimulation with fucoidan and various pathogen components (pattern recognition receptor, PRR ligands) was measured. As the results, fucoidan alone enhanced the production of interferon (IFN)-gamma by the Flt3-L-induced mixed BMDCs, and besides, fucoidan synergistically augmented IFN-gamma production with Pam3CSK4 (bacterial TLR1/TLR2 ligand) or Poly(I:C)/LyoVec (viral RIG-I ligand). On the other hand, their IFN-alpha productions were reinforced with Poly(I:C) (viral TLR3 ligand), ODN1585 (viral TLR9 ligand) and Poly(I:C)/LyoVec, although no synergic enhancement by fucoidan was observed. These results suggested that fucoidan was extremely effective in activating dendritic cells, which play a central role in the regulation of immune function to eliminate infectious pathogens. Supported by grants from JSPS KAKENHI (JP21K05423)

Fractionation and characterization of cell wall polysaccharides from the brown alga Cladosiphon okamuranus

Brown algae contain a polysaccharide-rich cell wall, mainly composed of alginate and fucoidan which have been extensively studied for their individual structure and bioactivities. Particularly, the cell wall of Cladosiphon okamuranus is rich in fucoidan rather than alginate. However, little is known about its arrangement or interlinking with other polysaccharides such as cellulose in the cell wall. To determine its structure in detail, the cell wall was sequentially fractionated into five fractions: hot water (HW), ammonium oxalate, hemicellulose-I (HC–I), HC-II, and cellulose. Almost 80% of the total cell wall recovered from alcohol insoluble residue in C. okamuranus consisted of HW and HC-I, which mainly contained fucoidan composed of fucose, glucuronic acid, and sulfate in molar ratios of 1.0:0.3:0.9 and 1.0:0.2:0.3, respectively. Methylation analysis revealed that fucoidan in HW and HC-I structurally differed in terms of content of sulfate, and sugar residue which was 1,4-linked xylose and 1,4-linked fucose. Small angle X-ray scattering measurements also showed distinct conformational differences between HW and HC-I. These structural heterogeneities of fucoidan may be related to their localization, and fucoidan in HC-I may be involved in reinforcing cell wall structure by cross-linking to cellulose.

Dengue and natural remedies for its prevention and control: A review

Dengue virus is the most common mosquito borne viral infection and is caused by four different serotypes of dengue virus, named DENV-1, DENV-2, DENV-3 and DENV-4, which belongs to Flaviviridae family and Flavivirus genus. It is transmitted by the Aedes mosquito from one infected person to another healthy person. A frontal headache, retro-orbital pain, body aches, rashes, nausea, vomiting, weakness and a high body temperature are the main symptoms of dengue infection. Dengue haemorrhagic fever and dengue shock syndrome can result in death in severe cases if proper treatment is not given. Several medical technologies, such as monoclonal antibodies, tetravalent subunits, inactivated and live attenuated vaccines have been adopted globally, but developing and under developed countries cannot afford them due to high costs. Various developing countries use herbal and natural remedies to prevent and control dengue. In this review, we are discussing about various plant species that have antiviral, ovicidal, larvicidal and mosquito repellent properties, as well as compound that can be used to treat dengue fever. Following species of plants Momordica charantia, Alternanthera philoxeroides, Andrographis paniculata, Cladosiphon okamuranus, Carica papaya, Momordica charantia, Andropogon citratum, Curcuma longa, Piper longum, Piper ribesoides, Piper sarmentosum, Eupatorium perfoliatum, Kaempferia parviflora, Solanum villosum, Azadirachta indica, Pongamia glabra, Eupatorium odoratum, Catharanthus roseus, Nyctanthes arbortistis, Acalypha alnifolia, Delonix elata, Ocimum sanctum, Tinospora rumphii, Citrus grandis, Jatropha curcas, Ageratum houstonianum, Albizia lebbeck, Aristolochia bracteata, Houttuynia cordata, Hippophae rhamnoides, Kaempferia parvifora, Leucaena leucocephala, Mimosa scabrella, Piper sarmentosum, Psidium guajava, Rhizophora apiculata, Boesenbergia rotunda and Quercus lusitanica are widely used for treatment and control of dengue. Plant products and herbal remedies provided alternative of medicine for cure and recovery of various diseases including dengue fever.

Evaluation of the morphological characteristics and culture performance of Cladosiphon okamuranus strains

This study aimed to determine whether morphological differences of Cladosiphon okamuranus strains at different aquaculture sites were inherent characteristics and to select useful forms for aquaculture production and processing. Three candidate strains with potentially excellent morphological characteristics, that is ON, SY and KT, were selected from six local strains collected from Okinawa Islands. Then, these three candidate strains were transplanted to four aquaculture sites to evaluate their characteristics. The thallus length was significantly larger (e.g. 1.6–2.1 times) in the SY strain than in the ON strain in each area and the density of the primary lateral branches of the latter was significantly (e.g. 2.4–5.9 times) higher than that of the other two strains. The SY and ON strain characteristics were also distinguished by a comprehensive evaluation of eight traits with principal component analysis. Conversely, the KT strain tended to have an intermediate length between ON and SY strains, the biomass yield of the SY and KT strains was higher than that of ON strain. These results, indicating that some morphological differences are intrinsic strain characteristics, will provide information to aquaculture producers using appropriate strains to maximize the unit yield and thalli quality.

Occurrence of different fucoidanase genes in Flavobacterium sp. SW and enzyme characterization

Fucoidans are hetero-sulfated polysaccharides that are widely distributed in brown algae and have been extensively studied for their various biological activities. The structure-function relationship of fucoidans remains unclear but can be studied using fucoidan-degrading enzymes (fucoidanases). Here, we isolated and identified Flavobacterium sp. SW as a microbial strain that can grow on fucoidan from Cladosiphon okamuranus as the sole carbon source. Genomic analysis of this strain revealed the presence of two genes, swfct and swfcn2, that are homologous to fct114 from Luteolibacter algae H18 and fcnA from Psychromonas sp. SW5A, respectively. The gene products were produced in Escherichia coli and showed significantly different specificities for fucoidan. Swfct catalyzed the degradation of deacetylated fucoidan from C.okamuranus, and Swfcn2 degraded fucoidans from Saccharina sculpera and Macrocystis pyrifera. The general properties of Swfct were examined by measuring the amounts of reducing ends produced by the enzymatic reaction, and the enzyme properties of Swfcn2 were evaluated by carbohydrate-polyacrylamide gel electrophoresis. Our findings indicate that one microbial strain can harbor genes encoding two different types of fucoidanases.

Development of DNA markers that distinguish male and female haploid germlings of the brown alga, Cladosiphon okamuranus

SUMMARYOkinawa mozuku, Cladosiphon okamuranus, is one of many edible brown algae, yielding 22 Kton annually and contributing ¥5 billion to the Japanese economy. The life cycle of C. okamuranus is complicated, since the alga has self‐cloning life cycles in both haploid (N, male and female) and diploid (2N) conditions, but only diploid “seeds” (germlings) become edible sporophytes. Because haploid and diploid germlings are morphologically indistinguishable, haploid germlings are often mistakenly combined with diploid germlings for cultivation, which results in less efficient harvesting of mozuku. Sexual identification of haploid germlings is essential to develop better diploid strains by crossbreeding. With this aim, we performed RNA‐seq analysis of haploid germlings of C. okamuranus. Using its decoded diploid genome and transcriptomic information, we identified 269 genes that are expressed specifically in male or female haploids. BLAST analysis with Ectocarpus siliculosus gene models revealed that nine of 269 genes were putative sex determination‐related genes of C. okamuranus. A unique set of polymerase chain reaction primers for these nine genes was designed, and DNA amplification using primers enabled us to distinguish male and female haploid and diploid germlings. This tool will enable mozuku farmers to select diploid germlings free of haploid germlings. Using this DNA marker technique, the amount of mozuku cultivated in Okinawa is expected to increase.

The anti-inflammatic activity of a sulfated polysaccharide Fucoidan in innate immune cells

Abstract Fucoidan is a series of natural sulfated polysaccharides derived from brown seaweeds and have reported to possess various biological activities such as anti-tumor, anti-virus, and immuno-modulatory effects. In previous study, we revealed that fucoidan derived from Cladosiphon okamuranus activated murine macrophage-like cell line RAW264 cooperatively with Zymosan, a Saccharomyces cerevisiae-derived β-glucan. On the other hand, several reports demonstrated that fucoidan inhibited lipopolysaccharide (LPS)-induced production of nitrogen oxide (NO) and inflammatory cytokines by RAW264 cells. Therefore, in this study, we investigated the potential of fucoidan derived from Undaria pinnatifida to regulate the excessive activation of RAW264 cells in response to overstimulation with pathogen components. RAW264 cells were inoculated at 20000 cells/well in 96-well culture plates, and after a recovery culture for 24 hr, the cells were treated with fucoidan with or without appropriate concentrations of each ligand for pattern recognition receptors (PRRs) including Toll-like receptors (TLRs). Whereas the production of NO was significantly enhanced with fucoidan alone, it was dose-dependently inhibited by fucoidan under stimulation with Pam3CSK4 (TLR1/TLR2 ligand), heat killed Listeria monocytogenes (HKLM, TLR2 ligand), LPS (TLR4 ligand), Pam2CGDPKHPKSF (FSL-1, TLR2/TLR6 ligand). These results suggested that fucoidan have beneficial ability to alleviate excessive inflammatory reaction during pathogenic infection and maintain suitable immune balance. Supported by Laboratory of Analytical Food Immunoscience belonging YM is a donated fund laboratory established in Faculty of Agriculture, Kyushu University by Ventuno Co., Ltd.

Topical application of fucoidan derived from Cladosiphon okamuranus alleviates atopic dermatitis symptoms through immunomodulation

Atopic dermatitis (AD) is a T helper (Th) 2 cell-mediated allergic disease, which features increased number of immunocytes and level of Th2-associated cytokines. Fucoidan is well known a naturally occurring agent effectively ameliorating many AD symptoms. Though these alleviative effects are exhilarating, the mechanisms behind, however, are still rather limited. In this study, we report that fucoidan derived from Cladosiphon okamuranus (FT) inhibits nitric oxide (NO) production by exerting its anti-inflammatory ability. Topical application on animals show that FT promotes skin repair, reduces immunocyte proliferation, and decreases serum IgE level. In histological analysis, FT favorably reduces epidermal hyperplasia and eosinophilic infiltration. The pharmacodynamics mechanism of FT is determined by means of down-regulating AD-associated cytokines (IL-4, IL-5, IL-22, IL-33, and TSLP) and up-regulating TGF-β1 level. Moreover, FT can regulate systemic immunity by enhancing tolerogenic dendritic cells (Tol-DCs) to activate regulatory T cells (Treg) differentiation and to decrease the population of Th22 and memory B cells. Overall, topical application of FT is able to enhance Treg secreting TGF-β1 and to down-regulate Th2 cell-mediated immunity so that AD symptoms are significantly alleviated. Thereby, FT is an ideal drug candidate potentially replacing or complementing corticosteroids to be developed and used as a therapeutic agent to treat AD.

Immunomodulation and mechanisms of fucoidan from Cladosiphon okamuranus ameliorates atopic dermatitis symptoms

Atopic dermatitis (AD) is a long-term allergic skin disorder that occurs most frequently in children. Currently, the common treatment of AD is corticosteroids; however, the drugs cause serious side effects. Therefore, there are many patients who seek complementary and alternative treatments such as healthy food. We report that fucoidan from Cladosiphon okamuranus (COP) exhibit exceptional immuno-modulatory effects significantly improving atopic dermatitis (AD) at both in vitro and in vivo levels: First, we performed the P815 cell degranulation assay, of which the results revealed that COP possesses anti-degranulation activity suggesting COP is very conducive to relieving allergic reactions of AD. Next, we performed the animal model examination, of which AD was significantly improved, suggesting COP can focally and globally modulate the immune systems of animals. The systemic improvements were manifested clearly by decreased epidermal hyperplasia, reduced infiltration of eosinophils, and decreased expression of AD-associated cytokines. Notably, COP reduced epidermal hyperplasia by downregulating the expression of IL-22. COP displayed therapeutic effects, which is comparable to corticosteroids but lack corticosteroid side effects, such as weight loss in our animal study. COP is multitudinous immunomodulatory abilities to serve as a healthy food supplement at the current stage, not least beneficial to atopic dermatitis.

Effects of Ingesting Fucoidan Derived from Cladosiphon okamuranus Tokida on Human NK Cells: A Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Pilot Study.

The aim of this study was to evaluate the effects of ingesting fucoidan derived from Okinawa mozuku (Cladosiphon okamuranus) on natural killer (NK) cell activity and to assess its safety in healthy adults via a randomized, double-blind, parallel-group, placebo-controlled pilot study. Subjects were randomly divided into two groups—a placebo group (ingesting citric acid, sucralose, and caramel beverages; n = 20; 45.5 ± 7.8 years (mean ± standard deviation)) and a fucoidan group (3.0 g/day from beverages; n = 20; 47.0 ± 7.6 years); after 12 weeks, blood, biochemical, and immunological tests were performed. Clinically adverse events were not observed in any of the tests during the study period. In addition, adverse events due to the test food were not observed. In the immunological tests, NK cell activity was significantly enhanced at 8 weeks in the fucoidan group, compared to before ingestion (0 weeks). In addition, a significantly enhanced NK cell activity was 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.

Regulatory mechanism of fucoidan-mix AG in intestinal mucosal immune cells

Abstract Fucoidan is a series of natural sulfated polysaccharides contained in brown sea algae, and their beneficial physiological activities such as anti-tumor, anti-virus and immune regulatory effects have been reported. In previous studies, we proved that fucoidans derived from Cladosiphon okamuranus (C. okamuranus) and Undaria pinnatifida effectively improved anti-tumor immunity and tumor vaccine efficiency in combination with an Agaricus blazei mycelium extract. It is thought that the fucoidan-agaricus mix (named fucoidan-mix AG) stimulate innate immune cells to activate intestinal and mucosal immune reaction, but actual target immune tissues and cells by fucoidan have not been evidenced yet. In this study, we investigated action mechanisms of fucoidan in regulation of mucosal immune activities. At first, immune cells were isolated from Payer’s patches, mesenteric lymph node (MLN) and intestinal epithelia of Balb/c mice, then stained with fluorophore-labeled fucoidan. As the results, it was revealed that fucoidan directly interact with lymphocytes besides dendritic cells and macrophages existing in these intestinal immune tissues. Furthermore, immune cells from Payer’s patches and MLN stimulated with fucoidan from C. okamuranus and fucoidan-mix AG produced more TNF-α, IL-12 and Th1 cytokine IFN-γ. The production of an immunosuppressive cytokine IL-10 also was augmented in the fucoidan-treated immune cells, which suggesting that fucoidan balanced immune system to prevent occurrence of excessive reaction. In addition, it was newly proved that fucoidan directly stimulated T lymphocytes to induce enhanced IFN-γ production.

Antioxidant and anti-norovirus properties of aqueous acetic acid macromolecular extracts of edible brown macroalgae

Previous studies reported the activity of fucoidans and polyphenols (phlorotannins) extracted from brown algae against enveloped viruses. The aim of this study was to investigate the effects of brown macroalgae on the non-enveloped norovirus. Aqueous acetic acid macromolecular (>3 kDa) extracts (AAEs) were obtained from ten samples of eight brown macroalgal species. Saccharides and sulphate composition, weight-averaged molecular weight, and total phenolic content (TPC) of the AAEs were measured to estimate their fucoidan and polyphenol content. Murine RAW264.7 macrophage cells and the human norovirus surrogate murine norovirus-1 (MNV-1) were used for the anti-norovirus assay. One hour of direct exposure to TPC-rich AAEs from Sargassum horneri (Sh), Eisenia bicyclis (Eb), Cladosiphon okamuranus (Co), and Undaria pinnatifida inactivated MNV-1. In contrast, pre-treatment of RAW264.7 cells for 20 h with AAEs from another U. pinnatifida sample, Analipus japonicus, and Co protected RAW264.7 cells against MNV-1 infection. The AAEs from Co contained high TPC and sulphated fucans (fucoidans) might be the most promising anti-norovirus agents as they directly inactivated MNV-1 and protected RAW264.7 cells from it. The AAEs of phlorotannin-rich Sh and Eb are also potentially effective at direct inactivating MNV-1.

Production of Carotenoids from Cultivated Seaweed.

Cladosiphon (C.) okamuranus, a brown alga endemic to the Nansei Islands, Japan, has been conventionally ingested as food. Nowadays, it is a major aquatic product of the Okinawa Prefecture with an annual production of around 20,000 tons. The life cycle of C. okamuranus comprises the macroscopic sporophyte (algal body) generation and the microscopic gametophyte generation. The germlings in the latter generation can proliferate when floating in seawater. This floating form has been exploited in techniques involved in the commercial production of C. okamuranus seedlings.Brown algae contain fucoxanthin, a carbonyl carotenoid known to have anticancer, anti-obesity, and antidiabetic effect in addition to the anti-oxidation effect. We found that the fucoxanthin content of cultivated floating form of C. okamuranus discoid germlings becomes up to 50 times that of the mature alga. Since the discoid germlings repeatedly grow like microorganisms, although they are large algae, they are utilized to produce fucoxanthin. We optimize the culture conditions by changing the temperature, light intensity, photoperiod, light wavelength, and nutrient salt conditions for optimal fucoxanthin productivity. The cultivation has been successful to industrial plant scale, culminating in the use of 1 ton of cultivating medium.In brown algal cells, fucoxanthin is primarily found bound to the photosynthetic pigment-protein complexes known as fucoxanthin-chlorophyll protein (FCP). Consequently cultivated floating form of C. okamuranus also shows high content of FCP. Isolation and characterization of pigments bound to the FCP were determined precisely, and ultrafast spectroscopies were applied to elucidate the photosynthetic function of fucoxanthin bound to the pigment-protein complexes. This cultivation method has also been applied to the other edible brown algae. We found that the optimal cultivation conditions as well as the yields of fucoxanthin and FCP highly depend on the species.The floating form cultivation was also applied to a large-sized edible green alga, Codium intricatum, which is uniquely producing a carbonyl carotenoid, siphonaxanthin. This has several anti-disease effects and is also a primal photosynthetic pigment which is found bound to photosynthetic antenna complex usually called siphonaxanthin-chlorophyll protein (SCP). We are working on the improvement of productivity, scale-up of production, and development of cultivation technology of new macro algae.