Studies on the Chemical Nature of Vitamin A

Abstract

EFFORTS to isolate and to determine the nature of the substance known as vitamin A received a great impetus when it was definitely established that the compound may be concentrated into that part of such substances as cod-liver oil which resists saponification Owing to the instability of the vitamin in the presence of substances tending to produce oxidation it is usually necessary, if loss is to be prevented, to carry out the saponification and extraction in an atmosphere of an inert gas such as nitrogen. When this precaution is taken, it is a comparatively simple matter to concentrate with little or no appreciable loss the vitamin A present in a litre of cod-liver oil into the 8 or 9 g. of unsaponifiable matter that this yields. Furthermore it has been demonstrated that this preparation also contains the whole of the anti- rachitic vitamin, or vitamin D, of the raw oil The value of concentrating these physiologi- cally important substances may be appreciated from two standpoints. In the first place it is obvious that there is a definite, if limited, need in clinical medicine for a preparation containing in highly concentrated form the com- ponents of the oil that are responsible for its therapeutic action; indeed, at least two patents have been taken out and are being operated for the technical preparation of such material for medicinal use. On the other hand the possession of a concentrated fraction, obtainable in reasonably large amounts, provides some encouragement for the attempt to isolate the active con- stituents.