20 THE ROLE OF ALGAE AND PLANKTON IN MEDICINE 



since alginate "wools" adsorb more bacteria on wiping than 

 does cotton. 136 

 6. As a replacement for tragacanth and other natural gums in the 

 manufacture of lubricating jellies. 104 



These diverse applications of the alginates utilize only a fraction of 

 the phycocolloid production of the United States. Most of it is serving 

 the dairy industry. By conservative estimate, for example, over half the 

 ice cream made is stabilized with algin to provide smoothness of texture 

 and body. Carragheenin has found some utility as a stabilizer in bakery 

 products. 48 



An antibiotic property has been attributed to some algal substances. 

 The natives of some Pacific islands wrap their fish catches in fronds of 

 certain local seaweeds to guard against rapid decomposition, 47 but no 

 specific antibotic has yet been identified here. The antiviral activity of the 

 algal polysaccharides sodium alginate, laminarin, and fucoidin has been 

 tested in chick embryos. 107 While no toxic effect upon the embryos was 

 noted, neither was there any upon the viruses. Pratt, Mautner, and their 

 associates 137 in 1951 demonstrated an in vitro inhibition of the growth of 

 Staphylococcus aureus, E. coli, and P. pyocyaneus by extracts of several 

 species of marine algae collected in California during the spring and fall. 

 The same investigators 138 in 1953 obtained in vitro inhibition of the 

 growth of several Gram positive and Gram negative pathogens with ether 

 extracts of the red alga Rhodomela larix. They assert that the effectiveness 

 of these algal substances is not due to their iodine content, but may be 

 on the basis of some brominated phenolic compound. 



The anticoagulant properties of algal substances have also received 

 some attention. Following the identification of heparin as a mucoitin 

 polysulfuric acid ester, and the finding that blood coagulation was in- 

 hibited by polysaccharides artificially esterified with sulfuric acid, Eisner 139 

 in 1937 began testing natural polysaccharide sulfuric acid esters for anti- 

 coagulant effect. Considerable anticoagulant activity was found in watery 

 extracts of the red algae Gelidium, Chondrus crispus, Iridea laminaroides, 

 and Delesseria sanguinea. The aqueous extracts of the brown algae Chor- 

 daria flagelliformis and Laminaria digitata also had anticoagulant powers, 

 but of a lesser degree. 140 The strength of these extracts was found to be 

 dependent upon such variables as seasonal fluctuations, length and extent 

 of drying of the algal fronds, the age of the extraction, and the amount 

 of heat to which the substances were subjected. Meunier, Molho, and their 



