An investigation of quebrachitol as a sweetening agent for diabetics

Abstract

QUEBRACHITOL (1-methylinositol) was first isolated by Tanret [1887] from quebracho bark. The latex of rubber trees contains about 2 %, and it was first obtained from this source by de Jong [1906], and has recently been prepared on a much larger scale by Rhodes and Wiltshire [1932]. The present study has been carried out at the instigation of the Rubber Research Association, to whom we are indebted for the supply of quebrachitol. No physiological experiments seem to have been carried out with quebrachitol, but the less soluble non-methylated l-inositol which is widespread in nature has been extensively studied, and the results fully reviewed by Needham [1926]. The quebrachitol which was supplied to us was an almost white crystalline powder. It dissolved readily in water in much the same way as glucose, but always left an amorphous brown residue, which looked a little like ferric hydr-oxide. This was filtered off before use. The chemical estimation of quebrachitol is difficult, and this was not undertaken in the blood, urine or intestinal residues, as this seemed unnecessary for the investigation in hand. To be a suitable sugar substitute for diabetics any material must satisfy three requirements. (1) It must have a pleasant sweet taste in relatively low concentration. If the substance has a high degree of solubility and will make a sweet syrup for cooking, so much the better. (2) It must not be metabolised as a sugar. (3) It must be free from harmful effects even in large doses. This last consideration is important, for the whole value of such a substitute is lost if it can only be taken in measured doses. The use of drugs to counteract any harmful effects is, of course, not to be considered. Quebrachitol has therefore been tested on these three points. 1. Taste. Quebrachitol has a sweet taste. In the opinion of a number of independent persons it was not nearly so sweet as glucose, which itself was not so sweet as cane-sugar. Some stated that quebrachitol had a metallic taste. Two kinds of fruit were cooked with quebrachitol. i lb. blackberries (120 g.) were stewed with (a) 7 g. quebrachitol, (b) 28 g. quebrachitol, (c) 14 g. cane-sugar, and (d) with no additions. Five people tasted these independently. All agreed that the blackberries stewed with cane-sugar were the sweetest. Only one person could detect any sweetening effect from the 7 g. of quebrachitol. All but one thought that 28 g. of quebrachitol made the fruit pleasantly sweet and as palatable, or nearly so, as the cane-sugar. One person stated that the que-brachitol merely conferred an unpleasant metallic taste, and preferred to have no sweetening rather than quebrachitol. In the second place 2 lb. (227 g.) of