SUGAR ALCOHOLS (POLYOLS) IN FUNGI AND GREEN PLANTS

Abstract

The previous article has demonstrated that acylic sugar alcohols (polyols) are more widespread in plants than was formerly appreciated. As Touster and Shaw (i962) point out, it is to be expected that many polyols have escaped detection during chemical analysis of tissues since, until recently, there have been few sensitive methods available for their detection. Furthermore, in some of the routine methods for the analysis of carbohydrates in plant extracts, polyols may be very easily overlooked. For example, on paper chromatograms, polyols have similar mobilities to their corresponding sugars in most of the commonly used solvents, and they do not react with most of the commonly used sugar detection reagents. Because of this, and because there have been some particularly useful recent developments in techniques, it has been felt necessary to present this survey of the methods now available for the study of polyols in plants. In the account that follows, polyols are generally considered alone, but it must be emphasized that they frequently coexist in plant extracts with free sugars. Particular attention is therefore given to methods which clearly distinguish polyols from sugars both in identification and in quantitative estimation. As in the previous article, glycerol and cyclitols will not be discussed. There is no single method which is universally applicable for the identification of all polyols. In preliminary analyses of plant material, paper chromatography is very frequently used. The application of this method is therefore discussed in some detail, particularly since it requires little specialized equipment and because it has proved most useful for examining experimental material after identification has been confirmed by other methods. The discussions of techniques other than paper chromatography will not be given in so much detail; this is not because they are any less valuable, but rather because we have had less practical experience with some of them and also because a number are very adequately reviewed elsewhere. The paper ends with a brief section giving suggested procedures for preliminary identification and determination of polyols in plant extracts.