“…porphyran from Porphyra and carrageenans from Eucheuma, also display antitumor properties as do brown algal polysaccharides from Sargassaceae and Laminariaceae (this study; Yamamoto et al, 1974 ;Ito & Sigiura, 1976 ;Takahashi, 1983 ;Usui et al, 1980 ;Yamamoto et al, 1982Yamamoto et al, , 1984aYamamoto et al, , 1984b . In particular, the ester sulfates of the polysaccharides may be related to the antitumor activity (Jolles et al ., 1962 ;Yamamoto et al, 1984b ;Yamamoto & Maruyama, 1985) . This assumption could be supported, in part, by our results, but it does not explain the low but positive effect of alginates .…”