Osazones of the uncommonly encountered reducing sugars

Abstract

Carbohydrates are polymers of sugar molecules that serve as storage molecules or as structural molecules. Chemically, carbohydrates are either aldehydes or ketones derivatives of polyhydroxylic compound known as aldoses and ketoses. Osazones are characteristic crystals resulting from the reaction of reducing sugars with phenylhydrazine. When detected, these osazones can be correlated with their associated disorders such as arabinose in autism & alzheimer's disease and galactose in Galactosemia. This study is to demonstrate the Osazone crystals of glucose, fructose, mannose, galactose, arabinose xylose, maltose & lactose sugars. One gram percent of the carbohydrate solution was used in the study. Osazone test was performed by treating carbohydrates with phenylhydrazine at 100°C and pH 4.3 for 10-20 mins. Each carbohydrate was identified by the shape of the crystals seen under Nikon eclipse 600 microscope. Osazone test has been one of the simplest means to differentiate between sugars, however it is exclusively being done only for certain sugars such as glucose, fructose, maltose & lactose. Studies show that in children with autism, arabinose concentrations may exceed 50 times the upper limit of normal. For many other disorders related to carbohydrate, there is a need to analyse the reducing sugars qualitatively also. For further evaluation, HPLC technique which gives high specificity can be used. These sugars can be identified qualitatively in biochemistry lab and can also be identified by paper chromatography or by thin layer chromatography.