MACROSCOPIC ALGAE (SEAWEEDS) 17 



Despite the many old traditional uses of algae in therapeusis, the 

 early twentieth century German medical lists included only Carragheen, 

 Agar-agar, Laminaria, and Fucus. The direct medicinal uses of macroscopic 

 algae have clearly undergone a marked decline. Certain extracts of sea- 

 weed are, however, of current significance in medical and para-medical 

 fields. The most important of these are agar, algin, and carragheenin. 

 They are extracted from algae by either water or alkali. Though they are 

 hydrophilic colloids, they have often been erroneously referred to as sea- 

 weed "gums." The term "phycocolloid" has been introduced as a more 

 correct designation. Aside from the medical areas, these extracts are also 

 of value in the drug, food, and cosmetic industries because of their proper- 

 ties as gelling, suspending, emulsifying, thickening, and body-producing 

 agents. 



Shabrin and Shapiro 101 in Russia have recently reported success in 

 treating trichomona! vaginitis with a Laminaria derivative. Monceaux 102 

 has enthusiastically advocated the use of the cellular plasma of marine 

 algae for a diversity of clinical conditions. He advises oral ingestion for 

 systemic diseases and deficiencies, and local application for dermatological 

 afflictions. Monceaux values seaweeds so highly because of the naturalistic 

 premise that they contain many of the therapeutically efficacious minerals 

 and trace elements present in sea water. 



Since its utilization by Koch 48 in 1881 for the culture and isolation 

 of pathogenic microorganisms, agar has become an important adjunct of 

 every hospital and bacteriological research laboratory. This dried and 

 bleached gelatinous extract of the red seaweed Gelidiaceae is produced 

 primarily by the Japanese; the British derive some agar from Gigartina. 

 It possesses the desirable property of absorbing water easily and swelling 

 up to a considerable extent. Only when heated to boiling does it dissolve ; 

 upon cooling it reverts to a somewhat colorless translucent gel. Agar is 

 good as a solid culture medium particularly because it is relatively inert, 

 not digested by most bacteria. It has also been used as a sealer and coat- 

 ing for pills, as well as a vehicle for lactic acid administered in intestinal 

 infections. 



Algin is the common name for derivatives of alginic acid, such as the 

 sodium, potassium, and ammonium salts and the propylene glycol ester. 103 

 The discovery of alginic acid and the production of algin therefrom is 

 credited to Stanford in 1885. 47 Alginic acid is the hydrophilic colloidal 

 polymer of anhydro-/?-D-mannuronic acid. It is extracted from the brown 

 algae, especially the giant kelp Macrocystis pyrifera, Laminaria digitata 



