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Blown algae like wakame (Undaria pinnatifida) and kombu (Laminaria sp.) are popular foods in East Asia. These edible algae have been used as rich sources of minerals, vitamins and dietary fibers. They have been attracted recently as multifunctional foods for maintaining our health.Fucoidan (fucan sulfate) is a fucose-containing sulfated polysaccharide from brown algae such as Fucus vesiculosus, 1) Ecklonia kurome, 2) and Cladosiphon okamuranus.3) Fucoidans showed various biological activities like anticoagulant 4) and antivirus. 5) In addition, fucoidan prevents microvascular thrombus formation induced by endothelial damage in arterioles and venules in vivo.6) It is suggested that this activity is not attributable to inhibition of P-and L-selectin but instead to the anticoagulative capacity of fucoidan. Thus, fucoidan might be useful for anticoagulant, antiviral, and anti-thrombus formation agent.Mekabu is a sporophyll of U. pinnatifida and it is also used as a safe, inexpensive and savory food in Japan. It has been reported that Mekabu has potential for chemoprevention of human breast cancer since Mekabu extract shows strong suppressive effect on rat mammary carcinogenesis.7) In addition, Mekabu fucoidan showed antitumor effect in vivo and its mechanism was mediated by IFN-g activated NK cells.8) Although Mekabu fucoidan has been subjected to different kinds of biological evaluation, its structural feature is still unknown. This paper describes the structural characterization of Mekabu fucoidan as well as evaluation for its antiviral effects. Results and DiscussionAfter washing and crushing the dried alga, it was treated with EtOH to remove lipophyllic compounds. The defatted alga was then extracted with 0.15 N HCl to prevent extraction of alginates. After neutralization and precipitation with 4 vol. of EtOH, crude fucoidan (CF) was obtained. CF was successively fractionated by ion exchange column chromatographies on DEAE Toyopearl 650M and Q-Sepharose FF and gel filtration on Sephacryl S-300 HR. As indicated in Fig. 1, CF was separated to four fractions. The most abundant fraction (CF-4) was further fractionated by Q-Sepharose (Fig. 2), and the second eluate (CF-4B) was collected. Then CF-4B was applied to a gel filtration on Sephacryl S-300 HR (Fig. 3) and the most abundant fraction was collected as purified fucoidan.The fucoidan was eluted as a single peak, and its apparent molecular weight was estimated to be 9000 by HPLC on TSK gel GMPW XL . In addition, the electrophoretic pattern indicated that the electric charge of fucoidan was homogeneous (Fig. 4). These results revealed that the fucoidan might be a homogeneous polysaccharide on the basis of molecular Medicine, Toyama Medical and Pharmaceutical University; 2630 Sugitani, Toyama 930-0194, Japan: and c Riken Vitamin Co., Ltd.; 3 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-8370, Japan. Received April 8, 2004; accepted June 9, 2004 Structural characterization and antiviral activities of fucoidan from sporophyll of Undaria pinnatifida (Mekabu) was exa...

Fucoidan from Mekabu (sporophyll of Undaria pinnatifida), a dietary alga, exerts antitumor activity possibly through enhancing the immune response. The present report describes the effects of dietary Mekabu fucoidan on the tumor growth of mouse A20 leukemia cells and on T cell-mediated immune responses in T cell receptor transgenic (DO-11 - 10 - Tg) mice. The animals were fed with a diet containing 1% Mekabu fucoidan (0.034 +/- 0.003 g/mouse/day) for 10 days and subcutaneously (s. c.) inoculated with A20 leukemia cells. Thereafter, the mice were fed with the diet containing fucoidan for 40 days. Mekabu fucoidan inhibited tumors by 65.4 %. We studied how the killer activities of T cell-mediated and natural killer (NK) cells are augmented in DO-11 - 10 mice fed with Mekabu fucoidan. The cytolytic activities of ovalbumin (OVA), which is specific against OVA-transfected A20 (OVA-A20) B lymphoma cells, and NK cells against YAC-1 were significantly enhanced in the mice fed with fucoidan compared with a basic diet. Thus, these findings suggested that Mekabu fucoidan mediates tumor destruction through Th1 cell and NK cell responses.

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1. We showed that a nutritional factor was able to attenuate the development of hypertension and its related diseases in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, the effect of Wakame, an edible brown seaweed, on the development of stroke was examined in SHRSP. 2. We studied the treatment with 5% (w/w in a diet) Wakame powder in salt-loaded (0.5% NaCl in drinking water) SHRSP. Salt-loaded animals treated with 5% cellulose or kaolin were used as controls. Wakame significantly delayed the development of stroke signs (P < 0.05) and significantly improved the survival rate of salt-loaded SHRSP (P < 0.05). There was no significant difference in the elevation of blood pressure among the three groups during the observation period. 3. We isolated fucoxanthin, a carotinoid, from Wakame powder and studied its preventive effect on ischaemic cultured neuronal cell death. Fucoxanthin significantly attenuated neuronal cell injury in hypoxia and re-oxygenation (P < 0.05). 4. Based on these results, we conclude that Wakame has a beneficial effect on cerebrovascular diseases in SHRSP, independent of hypertension. It is possible that fucoxanthin in Wakame may have a preventive effect against ischaemic neuronal cell death seen in SHRSP with stroke.