The Biological Utilization of Various Fat-Soluble Esters of Pyridoxine and 4-Desoxypyridoxine by Rats ,

Abstract

The biological activity of various esters of pyridoxine for the growth of rats has been tested. Pyridoxine triacetate, tripalmitate and trilinoleate were biologically utilized by rats as a source of vitamin B₆, and the activity was equal to that of pyridoxine hydrochloride. The results of the feeding experiments on diets supplemented with a suboptimal level of pyridoxine tripalmitate or pyridoxine hydrochloride appeared to indicate that the ester was less susceptible to destruction by the intestinal flora. The biological utilization of these supplements could not be differentiated by a single-dose assay. However, the growth-response tests to a single dose of a mixture of various preparations of pyridoxine and 4-desoxypyridoxine showed that, although the free forms of these active principles were more readily available than the esterified compounds, the latter were retained in the body for a longer period of time. The data appeared to indicate that at least a part of the long-chain fatty acid ester of vitamin B₆ could be stored in the body without complete hydrolysis. It was also shown that pyridoxine tribenzoate, pyridoxine tri-p-nitrobenzoate and pyridoxine tri-m-nitrobenzoate were biologically active as a source of vitamin B₆, though the activity of the latter two appeared to be extremely low.