Aphanothece Sacrum Research Articles

Photo- and Thermo-Chemical Properties and Biological Activities of Saclipins, UV-Absorbing Compounds Derived from the Cyanobacterium Aphanothece sacrum

Photo- and Thermo-Chemical Properties and Biological Activities of Saclipins, UV-Absorbing Compounds Derived from the Cyanobacterium <i>Aphanothece sacrum</i>

Extraction and isomerization of ultraviolet-absorbing substances, saclipins, from an edible cyanobacterium Aphanothece sacrum using subcritical water

Extraction and isomerization of ultraviolet-absorbing substances, saclipins, from an edible cyanobacterium Aphanothece sacrum using subcritical water

Evaluating the Use of Sacran, a Polysaccharide Isolated from Aphanothece sacrum, as a Possible Microbicide for Preventing HIV-1 Infection.

Since combination antiretroviral therapy (cART) was introduced to treat human immunodeficiency virus type-1 (HIV-1)/acquired immunodeficiency syndrome (AIDS), the AIDS mortality rate has markedly decreased, and convalescence in individuals with HIV has improved drastically. However, sexual transmission has made HIV-1 a global epidemic. Sacran is a megamolecular polysaccharide extracted from cyanobacterium Aphanothece sacrum that exhibits numerous desirable characteristics for transdermic applications, such as safety as a biomaterial, a high moisture retention effect, the ability to form a film and hydrogel, and an anti-inflammatory effect. In this study, we evaluated the anti-HIV-1 effects in sacran as a barrier to HIV-1 transmission. Sacran inhibited HIV-1 infection and envelope-dependent cell-to-cell fusion. Moreover, we used a Transwell assay to confirm that sacran inhibited viral diffusion and captured viruses. The synergistic effects of sacran and other anti-HIV infection drugs were also evaluated. HIV-1 infections can be reduced through the synergistic effects of sacran and anti-HIV-1 drugs. Our study suggests using sacran gel to provide protection against HIV-1 transmission.

Metal-Assisted Injection Spinning of Ultra Strong Fibers from Megamolecular LC Polysaccharides.

The molecular orientation of liquid crystalline (LC) hydrogels has the potential to induce a range of functionalities that can deliver great mechanical strength. Sacran is a supergiant LC polysaccharide isolated from the cyanobacterium Aphanothece sacrum with a high amount of anionic functional groups such as sulfates and carboxylates. In this article, ultra-strong sacran hydrogels and their dried fibers were produced by cross-linking under injection flow with trivalent metal ions such as Al3+, Cr3+, Fe3+, In3+, and rare-earth metal ions such Er3+ and Sr3+. Crossed-polarizing microscopy and X-ray diffraction imaging revealed a uniaxial molecular orientation in the LC gel fiber, resulting in outstanding mechanical characteristics.

Identification of Desiccation Stress-Inducible Antioxidative and Antiglycative Ultraviolet-Absorbing Oxylipins, Saclipin A and Saclipin B, in an Edible Cyanobacterium Aphanothece sacrum.

Aphanothece sacrum, a freshwater cyanobacterium, is an edible cyanobacterial strain. We identified two compounds belonging to the oxylipin family that possess UV-absorbing abilities and accumulate in the dried sample of A. sacrum. The compounds, named saclipin A and saclipin B, exhibited strong UV-absorption properties with the absorption maxima at 316 and 319 nm, respectively, and the molar extinction coefficients of 26,454 and 30,555 M-1 cm-1, respectively. The chemical structures of saclipins A and B have been elucidated, revealing that they have an all-E and a 12Z isomeric relationship within the triene structure. The saclipins could be isomerized by photoirradiation, with the cis-form saclipin B proving to be more stable in methanol, ethanol, or acetonitrile. Under drought stress conditions, the accumulation of saclipins A and B in A. sacrum was found to be increased 20- and 10-fold, respectively. Purified saclipins from A. sacrum showed biocompatibility and valuable bioactivities. Specifically, saclipins exhibited radical scavenging activity, maintaining their activity even 40 min after the reaction began. Additionally, they demonstrated inhibitory activity against glycation of elastin and collagen, which are constituents of dermal tissue. Notably, saclipins showed higher activity than the well-known glycation inhibitor aminoguanidine against collagen glycation.

The Use of Megamolecular Polysaccharide Sacran in Food and Biomedical Applications.

Natural polymer is a frequently used polymer in various food applications and pharmaceutical formulations due to its benefits and its biocompatibility compared to synthetic polymers. One of the natural polymer groups (i.e., polysaccharide) does not only function as an additive in pharmaceutical preparations, but also as an active ingredient with pharmacological effects. In addition, several natural polymers offer potential distinct applications in gene delivery and genetic engineering. However, some of these polymers have drawbacks, such as their lack of water retention and elasticity. Sacran, one of the high-molecular-weight natural polysaccharides (megamolecular polysaccharides) derived from Aphanothece sacrum (A. sacrum), has good water retention and elasticity. Historically, sacran has been used as a dietary food. Moreover, sacran can be applied in biomedical fields as an active material, excipient, and genetic engineering material. This article discusses the characteristics, extraction, isolation procedures, and the use of sacran in food and biomedical applications.

Oxylipins - biologically active substances of food

Oxylipins are biologically active molecules that are formed in all aerobic organisms enzymatically or as a result of the action of free radicals and reactive oxygen species. The value of oxylipins for plants is comparable to the value of eicosanoids for animals and humans. In the human organism, the oxylipins' formation occurs through enzymatic or non-enzymatic oxygenation of various ω-6 and ω-3 polyunsaturated fatty acids (PUFAs) obtained from food. Being "local hormones", oxylipins are involved in the regulation of inflammation, pain response, cell adhesion, migration and proliferation, apoptosis, angiogenesis, regulation of blood pressure, blood coagulation, and blood vessel permeability. There is a hypothesis that the molecular structure of oxylipins allows them to be positioned as adaptogens and justifies the use of plants as potential sources of oxylipins in traditional medicine. The aim of this research is a brief analytical review of publications characterizing the adaptogenic potential and promising sources of oxylipins (plant, cyanobacteria, and algae). Results. The publications of the last decade indicate an increased interest in the oxylipins of plants, cyanobacteria, and algae. In total, about 150 oxylipins and their derivatives are known in plants and fungi. Of the plant sources of oxylipins, Peruvian poppy root (Lepidium meyenii), white bryony (Bryonia alba L.), blackcurrant seed oil (Ribes nigrum), and licorice (Glycyrrhiza glabra) are of particular interest. Some macroalgae are capable of non-enzymatically or enzymatically synthesizing a variety of oxylipins, including antiinflammatory prostaglandins, resolvins, an d leukotrienes. In addition, to common oxidized derivatives of fatty acids, macroalgae also contain a number of complex and unique oxylipins. Other sour ces of oxylipin producers include macroscopic gelatin colonies of freshwater cyanobacteria Aphanothece sacrum. As the analysis of the presented in the review publications showed, most anti-inflammatory and pro-resolvent oxylipins have antiproliferative properties, have adaptogenic potential, and can protect the body at the system level, contribu ting to the formation of favorable bacterial clearance. Conclusion. The results of numerous studies indicate that plants, algae, and even bacteria can be a promising source of oxylipins, both for their use in their native form and for the targeted isolation of oxylipins from them in order to conduct further studies of their adaptogenic potential, cardio- and geroprotective properties. In the future , establishing the adequate daily intake of these substances and the development on their basis of dietary preventive and specialized products for various purposes will be relevant.

The cyanobacterial polysaccharide sacran: characteristics, structures, and preparation of LC gels

To shift from a petroleum-dependent society to a sustainable society using eco-friendly materials, polysaccharides from natural products are important candidates as alternative materials. We have researched one cyanobacterial polysaccharide, “sacran”, which is extracted from Aphanothece sacrum. In this review, the unique characteristics and structures of sacran and the preparation of liquid crystal gels are introduced: polymer properties such as megamolecular weight, that is, a weight > 107 g/mol; characteristic viscosity; liquid crystallinity (LC); fiber structures on the nanometer/micrometer scale; gel formation with heavy metal ions; photoshrinking in gels composed of metal ions; anisotropically swelling gels; orientation upon drying of the air-LC interface; meniscus splitting; and membrane formation with uniaxial orientation, which are the results of self-organization. These matters are discussed particularly from the perspectives of polymer science, colloidal science, gel science, etc. We expect that sacran will be applicable in a variety of fields, such as tissue engineering, pharmacodynamics, and biomedical materials, with possible contributions to the development of a sustainable material society. To shift from a petroleum-dependent society to a sustainable society using eco-friendly materials, polysaccharides from natural products are important candidates as alternative materials. We have researched one of the cyanobacterial polysaccharides, “sacran,” which is extracted from Aphanothece sacrum. In this review, the unique characteristics, structures, and preparation of sacran LC gels are introduced. These matters are discussed especially from the perspectives of polymer science, colloidal science, gel science, etc. We hope that sacran will be used in a variety of fields, such as tissue engineering, pharmacodynamics, and biomedical materials, with possible contributions to the development of a sustainable material society.

Structure and Properties of Hybrid Film Fabricated by Spin-Assisted Layer-by-Layer Assembly of Sacran and Imogolite Nanotubes.

A free-standing (biomacomolecule/synthetic inorganic nanotubes) hybrid film was fabricated through an alternative layer-by-layer (LBL) assembly of sacran and imogolite nanotubes. Sacran is a natural polysaccharide extracted from the cyanobacterium Aphanothece sacrum, while imogolite is a natural tubular aluminosilicate clay found in volcano ash. The hybrid film thickness increased linearly with the number of the bilayers, because of the interaction between the negatively charged surface of sacran and the positively charged surface of imogolite. UV-vis spectroscopy indicated that the LBL film exhibited good transparency. The surface morphology of the LBL film was smooth in the micrometer scale; many imogolite nanotubes were adsorbed onto the sacran layer, while no imogolite clusters were observed. Furthermore, the structure, stability, gas permeability, and mechanical properties of the LBL films were investigated.

Preventive Effects of Aphanothece sacrum on Diabetic Cataracts

Approximately 20% of diabetic patients develop diabetic cataracts. As lens proteins are known to be only slightly metabolized during the lifetime, cataracts are difficult to recover from once they have progressed. Therefore, the daily intake of natural compounds would be an important strategy for the prevention of diabetic cataracts. Aphanothece sacrum Okada (Asa) is a freshwater blue-green algae endemic to Japan. It has been eaten since the Edo period in Kyushu. In this study, the inhibitory effects of Asa on the pathogenesis of diabetic cataracts were evaluated. Furthermore, the inhibitory effects of Asa on the formation of Nε-(carboxymethyl) lysine (CML), an oxidation-dependent advanced glycation end-product, were also measured. After 3-month administration, the CML contents in the lens were measured by liquid chromatography tandem mass spectrometry using an internal standard of CML or lysine. Asa significantly inhibited the progression of cataractogenesis and accumulation of CML in diabetic lens compared with the normal diet group. These results suggested that daily intake of Asa reduces oxidative stress and prevents the pathogenesis of cataracts.

Industrial and Medical Material Applications of a Mega-polysaccharide Derived from Cyanobacteria

Polysaccharides (PS) are one form of biomass occurring in great abundance on earth and are promising organic material alternatives to petroleum-based ones. We have focused on PS produced by cyanobacteria. Aphanothece sacrum, which is a freshwater unicellular cyanobacterium, produces large amounts PS as a main component of the extracellular matrix. We successfully extracted the PS sacran from A. sacrum biomaterials and demonstrated that sacran contains carboxyls and sulfate groups. Furthermore, the constituent sugars of the sacran extracted were determined to be fucose, rhamnose, xylose, arabinose, mannose, glucose, galactose, glucuronic acid, galacturonic acid, and galactosamine. The sequence of sacran is still under investigation. In addition, we confirmed that the sacran was a supergiant with a high absolute molecular weight of 2.35×107 g/mol. Sacran shows a self-orienting behavior in dilute solution at a concentration range over 0.25 wt% to form a liquid crystalline structure. Using this property, it is possible to prepare a sacran cast film with an orientation structure, especially swelling in the thickness direction, to form anisotropic hydrogels. The anisotropy and degree of swelling of the hydrogels could be controlled by varying the heating temperature of the sacran cast file. Furthermore, sacran could be combined successfully with rayon as new fiber materials, and the sacran-rayon complex materials showed increased water absorption compared with the original rayon. This article introduces various applications of sacran in the industrial and medical fields.

Fascination of Cyanobacterium Aphanothece sacrum and Sacran as Functional Materials

Fascination of Cyanobacterium Aphanothece sacrum and Sacran as Functional Materials

Potential Use of Sacran for Dermal and Oral Preparations

Sacran, a new polysaccharide isolated from cyanobacterium Aphanothece sacrum (Sur.) Okada, is known to have potential as an active pharmaceutical ingredient (API) for the treatment of atopic dermatitis, various types of dermatitis, skin wound, hemorrhoids and corneal epithelium disorder. In the present studies, the effects of sacran on skin injury and skin pain induced by stratum corneum tape-stripping and gastric ulcer induced by indomethacin, a non-steroidal anti-inflammatory drug (NSAID), and hydrochloride/ethanol (HCl/EtOH) in mice were investigated. Sacran solution 0.05% (w/v) showed greater reduction of skin injury and skin pain induced by stratum corneum tape-stripping, compared to that of 0.01% (w/v) and 0.1% (w/v) sacran solutions. In addition, the inhibitory effects of 0.05% (w/v) sacran on skin injury and skin pain induced by tape-stripping were significantly superior to 0.05% (w/v) hyaluronic acid solution. On the other hand, 1.0% (w/v) sacran solution significantly inhibited gastric ulcer formation induced by indomethacin, compared with 1% (w/v) dextran solution and the inhibitory effect of sacran was comparable to that of the positive control omeprazole. In addition, 1% (w/v) and 2% (w/v) sacran solution reduced HCl/EtOH-induced gastric ulcer in mice, with the alleviative effect of sacran was comparable to or greater than that of the positive control sodium alginate. These results suggest that sacran has potential as API to treat skin injury and pain induced by tape-stripping and gastric ulcer induced by NSAIDs and EtOH.

Preparation and evaluation of freeze dried surface-deacetylated chitin nanofiber/sacran pellets for use as an extended-release excipient

Pelleted preparations were formulated from sacran (Sac), an anionic, sulfated, carboxyl-containing polysaccharide, which is extracted from the Japanese indigenous cyanobacterium Aphanothece sacrum, and surface-deacetylated chitin nanofibers (SDACNF). The use of this material as an extended-release excipient for tetrahydrocurcumin (THC), a model drug that is used to treat wounds via its radical scavenging ability was examined. The THC used in the study was complexed with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), which increases its water solubility. The radical scavenging activity of the THC/HP-β-CD complex (molar ratio of 1:1) was significantly higher than the values for SDACNF or Sac alone. The rate of release of THC from the Sac/SDACNF pellets containing the THC/HP-β-CD complex decreased with increasing Sac content in the pellet, suggesting that Sac/SDACNF (1:1) and Sac alone pellets function as extended-release excipients for THC. The findings reported here indicate that this can be attributed to the ability of the Sac component to retain fluids, thus extending the effects of the drug. In view of the above experimental outcomes, i.e. wound healing efficacy, fluid absorption, retention and the extended drug release of the system indicates that this preparation, in the appropriate ratios, has the potential for use as a controlled-release drug in wound healing.

Defensive Effects of a Unique Polysaccharide, Sacran, to Protect Keratinocytes against Extracellular Stimuli and Its Possible Mechanism of Action.

Sacran, a polysaccharide isolated from the alga Aphanothece sacrum (Suizenji-nori), has unique physical and physiological characteristics. In a previous study, we reported that sacran improves skin conditions in individuals who suffer from atopic dermatitis (AD), focusing on its trapping function against extrinsic stimuli compared with hyaluronic acid (HA). First, we examined the penetration of sacran through stratum corneum (SC) with an impaired barrier function using immature reconstructed human epidermal equivalents. Sacran penetrates the SC to living cell layers of the epidermis, which suggested that sacran would attenuate adverse influences in keratinocytes caused by extracellular factors such as irritants or proinflammatory cytokines such as interleukin 1α (IL-1α). Sacran markedly reduced the cell damage induced by a nonionic detergent, sodium lauryl sulfate (SLS). Moreover, sacran restored the elevation of intracellular reactive oxygen species (ROS) levels stimulated by SLS and by IL-1α. These effects of sacran were superior to those of HA. In order to investigate the restoration effects of sacran, the influence of sacran on the physical properties of lipid bilayers was evaluated by measuring the order parameter using the ESR spin-labeling method. Because sacran failed to cause changes in the order parameters of liposomes and HaCaT keratinocytes, these results indicate that sacran does not interact with lipid bilayers although it restored changes in the order parameter caused by SLS. The sum of these results demonstrates that sacran reduces the influence of extracellular stimuli by its trapping effects. We conclude that the improving action of sacran is based on its trapping effect.

Twisting Fibers Formation of Cyanobacterial Supra-Polysaccharide through Self-Assembly

Biopolymers such as polysaccharides, cytoskeletal proteins, and DNAs show helical structures in molecular scale and self-orientation in larger scale. Sacran is one of fascinating bacterial polysaccharides which could naturally form incredibly giant fiber in micrometer scale. It is extracted from cyanobacteria, Aphanothece sacrum, which has attached our interest due to the extremely high molecular weight (> 1.6 × 107 g/mol)1 and the self-orienting giant micro-fibers (~1 μm of outer diameter and > 20 μm length)2 during the drying process which cannot encounter in any other soluble polysaccharides. From our previous researches, we found that in drying process of the sacran solution, the rigid polysaccharides exhibit self-orientation and they gather to build a rod-like microdomain in micrometer scale. Moreover, in some conditions, it shows clear twisting structure in micrometer scale. Here, we study the fiber formation using polarized optical microscope and scanning electron microscope to clarify the effect of polymer’s initial concentration, evaporation speed and ionic effect on the fiber formation. This unique formation is significant not only to understand basic fiber natural formation but also to develop for material field applications. The formation mechanism was investigated in micrometer scale from drying process using polarized optical microscope (POM) and scanning electron microscope (SEM). The samples were prepared by drying the 1 μL droplet on a glass substrate at room temperature under control of the initial polymer concentration. From the drying records of a solution (5 × 10-1 wt%), we could confirm three main regions with different morphologies. Around the record of the droplet edge, fibers which oriented apparel to the contact line were clearly observed. In the middle of the record, the twisting fibers in random direction were shown. In the center, dendrite crystal structures could be observed. These results suggest that the sacran forms variety of geometric structures under drying environment and mild condition. Focusing on the fibers at the edge and middle area of sacran droplet, the deposition from 5 × 10-3 wt% solutions showed not only particles but also short fibrous with ~1 μm diameter as main structures. In contrast, deposition from a solution at higher concentration of 5 × 10-2 wt%, giant fibers in micrometer scale were observed. It is clearly seen that self-assembly of loosely-twisting fibers led to form larger structures through snaking or bundling. Considering the different diameter of the micro-rods and the twisting fibers as shown in Fig.1, the loosely-twisting fibers could be observed and they showed a semi-rigid fiber characteristic which causes low orientation around the droplet edge. As for the deposition from 5 × 10-1 wt% solutions, rigid fibers were observed with high orientation around the droplet edge. This might be owing to tightly-twisting fibers at high concentration. The effect of evaporation speed is one of the main factors which effects to the polymer morphology. At low evaporation speed, straight sacran fibers were observed. However, when evaporation speed was increased, the straight fiber transform to snaking or twisting form. The effect on assembly and disassembly of the fibers were also clarified by mixing various kinds of ionic (HCl, NaCl and CaCl2) with various concentrations (1, 5, 10, 60 mM). Sacran fibers were disassembled in all concentration of HCl and NaCl due to carboxylic groups were interacted by monovalent cations. In case of CaCl2, calcium divalent cations could bind with the carboxylate groups as crosslinker. Therefore, it remained fibers assembly of sacran. This unique formation is not only important to understand basic helical natural fiber formation which still being an ambiguous issue but also to develop new environmental friendly material in several fields such as electro optical film, bio-mimic templating and components of medicines in near future. 1) Okajima, M. K., et al., Macromolecules 2009, 42, 3057.2) Okeyoshi, K., et al., Biomacromolecules 2016, 17, 2096. Figure 1

Physiological properties and genetic analysis related to exopolysaccharide (EPS) production in the fresh-water unicellular cyanobacterium Aphanothece sacrum (Suizenji Nori).

The clonal strains, phycoerythrin(PE)-rich- and PE-poor strains, of the unicellular, fresh water cyanobacterium Aphanothece sacrum (Suringar) Okada (Suizenji Nori, in Japanese) were isolated from traditional open-air aquafarms in Japan. A. sacrum appeared to be oligotrophic on the basis of its growth characteristics. The optimum temperature for growth was around 20°C. Maximum growth and biomass increase at 20°C was obtained under light intensities between 40 to 80 μmol m-2 s-1 (fluorescent lamps, 12 h light/12 h dark cycles) and between 40 to 120 μmol m-2 s-1 for PE-rich and PE-poor strains, respectively, of A. sacrum . Purified exopolysaccharide (EPS) of A. sacrum has a molecular weight of ca. 104 kDa with five major monosaccharides (glucose, xylose, rhamnose, galactose and mannose; ≥85 mol%). We also deciphered the whole genome sequence of the two strains of A. sacrum. The putative genes involved in the polymerization, chain length control, and export of EPS would contribute to understand the biosynthetic process of their extremely high molecular weight EPS. The putative genes encoding Wzx-Wzy-Wzz- and Wza-Wzb-Wzc were conserved in the A. sacrum strains FPU1 and FPU3. This result suggests that the Wzy-dependent pathway participates in the EPS production of A. sacrum.

Anti-allergic Effects and Immunomodulatory Activity of Sacran, a Bioactive Compound from River alga Aphanothece sacrum

Sacran is a newly discovered sulfated glycosaminoglycan-like compound extracted from river alga Aphanothece sacrum (Suizenji-nori in Japanese). The present study evaluated the clinical effects and immunomodulatory activity of topical sacran in a murine model of contact allergy and in vitro . Two experiments were conducted to evaluate sacran’s effect on cell degranulation and the release of b -hexosaminidase release by RBL-2H3 basophilic cells in a model of IgE-mediated allergic reaction in vitro, and the curative effects and immunomodulatory activity of topical application of sacran on hapten-induced eczematous skin lesions in mice. In the in vitro experiment, RBL-2H3 basophilic cells were sensitized with DNP-specific IgE, and b -hexosaminidase release activity was evaluated by ELISA. In the in vivo experiment, 24 NC/Nga male mice, including six normal and three treatment groups of six mice with hapten-induced contact allergy were used. Diseased mice were topically treated either with 20 mL of 2% sacran, 10 mg/ml hydrocortisone (HCT) or phosphate buffered saline (Control). Clinical severity of skin lesions was evaluated, and blood samples were collected to determine the serum levels of the following biomarkers: eotaxin, MCP-1, IgE, IFN-g, IL-4 and IL-5. Skin specimens were taken to determine gene expression levels of IFN-gmRNA, TNF-amRNA, and IL-4 mRNA by RT-PCR. Results of the in vitro experiment showed that sacran solutions inhibited RBL-2H3 cell degranulation and the release of b -hexosaminidase, as significantly low levels of this enzyme were found for sacran-treated cells (vs. control solution; p<0.05). In the in vivo experiment, topical application of sacran markedly reduced serum IL-4, IL-5, total IgE, eotaxin, MCP-1 in allergic mice. In addition, TNF-amRNA gene expression level in lesional mouse skin was also reduced in sacran group as compared with buffer-treated controls (p<0.05). Furthermore, topical sacran, and hydrocortisone as well , alleviated skin symptoms (scaling/dryness, erythema/hemorrhage and erosion/excoriation) and reduced ear thickness (vs. controls). This study showed that sacran inhibited the release of b -hexosaminidase by allergen-challenged RBL-2H3 basophilic cells, exerted anti-inflammatory activity on eczematous skin lesions and downregulated TNF-amRNA expression in mice. These findings suggest that sacran has a potential to serve as an alternative remedy for skin allergic disorders.

Super Liquid Crystalline Polysaccharides Produced by Ultimately-ecological Microreactors

Cyanobacteria fix carbon dioxide and nitrogen from the atmosphere using solar energy to produce various biomolecules, and thus are regarded as ultimately ecological microreactors. Sacran is a cyanobacterial polysaccharide with a very high molecular weight of 29 Mg/mol, which is extracted from Aphanothece sacrum cyanobacterium mass-cultivated in freshwater environments such as river or spring. Sacran is a water-soluble heteropolysaccharide comprising more than 6 kinds of sugar residues and contains 12% sulfate anionic groups and 27% carboxyls. Sacran has a super-absorbent function of water, which can retain 6000 mL for 1 g specimen, due to very long hydrating chains. The value is much higher than hyaluronic acid or conventional super-absorbent polymers. Sacran exhibits self-orienting behavior in dilute solution at a concentration range over 0.25 wt%, which is quite low when compared with conventional liquid crystalline polysaccharides. Mesogenic helical chains of sacrans have extremely high aspect ratios of 1600 for highly persistent lengths of 32 micrometer. Through the liquid crystallinity, sacran solution shows a shear-thinning behavior and the solution spread over a substrate such as biological skin very efficiently to create a thin layer. Applied on atopic dermatitis skin sacran solution exerts excellent moisturizing effect and anti-itching action.

Potential Use of Sacran Hydrogels as Wound Dressing Material

A wound dressing is one of the essential approaches to prevent further harm to cutaneous wounds as well as to promote wound healing. Therefore, to achieve ideal wound healing, the development of advanced dressing materials is necessary. Sacran, a novel megamolecular polysaccharide derived from the cyanobacterium Aphanothece sacrum, has a very high molecular weight that exceeds 107 g/mol and water-superabsorbent capacity. Recently, we demonstrated that sacran exerts anti-inflammatory activity by ameliorating the skin barrier function in patients with atopic dermatitis. In this study, to develop and characterize sacran hydrogel films (Sac-HGFs) for wound dressing materials, we prepared a physically crosslinked-Sac-HGFs, and evaluated their physicochemical properties, cytotoxicity, skin hydration and wound healing ability. Additionally, we encapsulated curcumin, as a model drug for wound healing, into Sac-HGFs by complexation with 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CyD), and investigated their potential for wound dressing application. Sac-HGF has potentially good properties for wound dressing application, due to not only the moisturizing effect but also the anti-inflammatory effect of sacran. Additionally, Sac-HGF has the potential to deliver water soluble complex of curcumin/HP-γ-CyD at the wound site and thereby promote wound healing. These findings may be useful information for preparation of wound dressing materials using sacran, CyDs and drugs.