An Evaluation of Folic Acid

Abstract

FOLIC (PTEROYLGLUTAMIC) ACID is the most recently identified and synthesized member of the vitamin B complex. Its unexpected beneficial effect on certain types of anemia has stimulated much interest from both therapeutic and experimental standpoints. As is often true, the effort of many investigators working independently over a period of many years has led to our present knowledge of folic acid. In 1938 a hitherto unknown member of the vitamin B complex was found to be necessary for the proper growth of chicks(1) and was called Factor U. A year later it was demonstrated that deficiency of some unknown factor present in liver caused failure of growth and development of anemia in chicks (2) and this factor was named vitamin B, (i.e., vitamin B for the chick). The material was subsequently isolated from liver in pure form (3). In 1940, an unknown constituent of yeast was proved to be necessary for the growth of the bacterium, Lactobacillus casei (4). This material, adsorbable on a charcoal preparation, norite, was called the "norite eluate" factor or L. casei factor. Investigations upon monkeys .revealed that deficiency of a substance, subsequently termed vitamin M, resulted in failure of growth, leukopenia, and anemia (5,6). The L. casei factor was effective in relieving the vitamin M deficiency in monkeys, thus indicating the biological identity of the two substances. In 1941, it was demonstrated that another bacterium, Streptococcus lactis R required an unknown substance for growth (7). This was naturally called the S. lactis factor and the name folic acid (i.e., foliage) was also assigned to it since it was obtained from spinach and other green leaves. Identification and Synthesis.-In 1945 the identification and synthesis of the L. casei factor was announced (8, 9) and the chemical name, pteroylglutamic acid, was suggested. The compound consists