Antitumor effects of seaweed polysaccharides (fucoidan)

1. Antitumor effects of seaweed powder
2. Table 3. Meth A fibrosarcoma transplanted into mice growth inhibition rate through seaweed extract powder intra-abdominal injection (%)
3. Antitumor effects of seaweed polysaccharides
4. Table 4. Antitumor effect on sarcoma 180 (Nakazawa, 1976)
5. Table 6. Ehrlich carcinoma transplanted into mice growth inhibition rate through polysaccharide (extracted from seaweeds) oral administration (%)
6. Table 7. Meth A transplanted into mice growth inhibition rate through polysaccharide (extracted from seaweeds) intra-abdominal administration (%) (Noda et al., 1989)

Antitumor effects of seaweed powder

Noda et al. formed a research group concerned with antitumor properties of seaweed and conducted research on antitumor activity with respect to polysaccharides and lipids contained in many seaweeds. First, in order to discover antitumor activity in a variety of different seaweeds, they investigated 4 species of green algae, 24 species of brown algae, and 28 species of red algae. They transplanted solid Ehrlich tumors in mice that had been administered 14 days of these seaweed powders, administered them for another 14 days, and sought to determine tumor growth inhibition rates. The results showed high inhibition rates in 3 green algae species, such as Enteromorpha prolifero, 8 brown algae species, such as Scytosiphon lomentaria and Laminaria japonica, and 5 species of red algae, such as Porphyra yezoensis. Further, after transplanting Meth A fibrosarcoma, they administered 7 rounds of seaweed powder intra-abdominally over 21 days and looked at the effects, obtaining high values in the range of 35-56% in the following species in order: Sargassum patens, Sargassum ringgoldianum, Laminaria angustata, Ecklonia cava, Chondrus crispus. Of these results, the effects on solid Ehrlich carcinoma are shown in table 2 and effects on Meth A fibrosarcoma in table 3. Solid Ehrlich carcinoma inhibition rates of roughly 40% or higher were observed in 18 out of 57 species of seaweed, with brown alga Scytosiphon lomentaria showing the highest rate at 69.8% and Lessonia, also a kind of brown algae, at 60%. In Meth A, activity was shown in 10 out of 24 species of seaweed with Sargassum the highest at 55.5%, followed by Kotoni Eucheuma muricatum and Sargassium ringgoldianum.

Antitumor effects of seaweed polysaccharides

Because of the factors mentioned above, research was conducted using fucoidan and alginic acid. Here we will go over the results of the studies that have made use of fucoidan and substances that appear to be fucoidan. First, Nakazawa et al. administered fucoidan-like substances prepared from Sargassum horneri and Eisenia bicyclis intra-abdominally to mice transplanted with sarcoma 180 solid tumors and examined tumor growth suppression rates. They identified antitumor effects based on the observed suppression rate of about 60% for Sargassum horneri as shown in table 4.

* Transplanted cells equaled to 2 x 10(6) per mouse

Table 5, also reported in 1976, in research looking at the antitumor effects of Sargassum horneri and Sargassum thunbergii on Ehrlich ascites cancer, shows the number of days of survival beyond the untreated group enabled by the longevity effects of administering a Sargassum horneri polysaccharide fraction intra-abdominally, as well as with Sargassum thunbergii. When the method of preparation and structural components are considered, the antitumor effects of Sargassum thunbergii seen here can be taken to result from fucoidan. It has also been reported that polysaccharide fractions obtained from brown algae such as Sargassum fulvellum have tumor growth inhibition and life-prolonging effects on Ehrlich ascites cancer and sarcoma 180. The Noda et al. research group mentioned above has also investigated the antitumor effects of polysaccharides and lipids.

Here, with regard to polysaccharides, table 6 shows the results with respect to solid Ehrlich carcinoma when 17 types of polysaccharide originating in seaweeds were administered orally. Relatively high inhibition rates were observed, with the inhibition rate of lambda carrageenan originating from Chondrus crispus at 51.4-63.2%, and that of fucoidan originating from Undaria pinnatifida at 51.7-56.7%. The results in table 7 show that fucoidan originating from Undaria pinnatifida and Sargassum ringgoldanium had relatively high inhibition rates with respect to M-A fibrosarcoma when administered intra-abdominally.

For reference:

1. Noda et al. 1989. Nippon Suisan Gakkaishi, 55, 7, 1259-1264
2. I.Yamamoto at al. 1982. Bot. Mar., 25, 455-457