The goal of this study was to investigate the topical anti-inflammatory effects of the megamolecular polysaccharide sacran extracted from cyanobacterium Aphanothece sacrum using various inflammatory animal models. Sacran showed potent anti-inflammatory effects with optimum effective concentrations at 0.01 and 0.05% (w/v). Sacran markedly inhibited paw swelling and neutrophil infiltration in carrageenan-induced rat paw edema. Additionally, 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionyl-carboxylic acid (DMEQ)-labeled sacran had the ability to penetrate carrageenan-induced rat paw skin rather than normal skin. Also, sacran significantly suppressed kaolin-induced and dextran-induced rat paw edema throughout the duration of the study. Key words sacran; polysaccharide; anti-inflammatory effect; phlogistic agent Inflammatory responses are complex events of the body as it delivers the appropriate defense against harmful stimuli. Inflammation is partially regulated by carbohydrates, especially sulfated glycosaminoglycans, expressed on the surface of endothelial cells and leukocyte cells. Exogenous sulfated glycans, such as heparin, heparan sulfate, dermatan sulfate, chondroitin sulfate, fucosylated chondroitin sulfate and fucoidans can induce anti-inflammatory effects. The anti-inflammatory effects of these sulfated glycans are the competitive inhibition of the molecular interactions between sulfated glycans and P-selectin or L-selectin, while other mechanisms of action, such as down-regulation of chemokine and transcription factor activities can also occur.Skin operates not only as a protective physical barrier, but also as a dynamic organ that has other recognized functions, such as endogenous homeostasis, metabolism, and sensory input. Moreover, skin actively contributes in immunological regulatory processes and inflammatory responses.1) There is a wide range of dermatological conditions that include inflammatory skin disorders ranging in severity from mild skin rash to severe dermatitis. Nowadays, corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly administered to reduce the inflammation. However, they can frequently cause a number of serious adverse effects. 2,3)Hence, great efforts have been devoted towards the discovery of new and safe anti-inflammatory natural products of plant origin as alternatives. 4,5) Importantly, numerous beneficial effects of plant polysaccharides have been demonstrated on human health to exhibit a spectrum of biological activities such as anti-inflammatory effects.6,7) Meanwhile, plant polysaccharides may have the potential to induce the allergic response. Therefore, plant polysaccharides with high safety are necessary.Recently, a novel sulfated polysaccharide sacran attracts a considerable amount of attention. It is extracted from the Japanese indigenous cyanobacterium Aphanothece sacrum, which possesses a jelly-like extracellular matrix (ECM) with high water content (97.5-98.3%). [8][9][10][11][12] Sacran is a heteropolysaccharide composed of various s...

A megamolecular polysaccharide sacran was newly extracted from cyanobacterium Aphanothece sacrum. Sacran has many preferable properties for transdermal application, e.g. a safe biomaterial, a high moisturizing effect, a formation of film and hydrogel. Additionally, it was recently discovered that sacran has an anti-inflammatory effect for atopic dermatitis model mice. In this study, in order to evaluate the feasibility of sacran-hydrogel as a novel sustained release system, we prepared a sacran-hydrogel containing 4-biphenyl acetic acid (BPAA, an acidic drug), prednisolone (PD, a neutral drug) or chlorpheniramine maleate (CPM, a basic drug), and performed the in vitro release studies. The sacran-hydrogel containing BPAA, PD or CPM provided a sustained release profile in accordance with a quasi-Fickian diffusion model. Furthermore, the release rate of drugs from sacran-hydrogels can be controlled by adjusting the concentration of aluminum chloride as a cross linker. These results suggest the potential use of sacran-hydrogel as a sustained release system for drugs.