Simple method for the determination of polysaccharides in herbal syrup

Abstract

This article describes optimized isolation procedures that enable simple quantification of polysaccharides in herbal sirup. Isolation of polysaccharides present in the herbal sirup was made by both precipitation and ultrafiltration. Quantification of sirup polysaccharides was performed with gravimetric and spectrophotometric methods. The first step of the spectrophotometric method was separation of polysaccharides from mono- and oligosaccharides by precipitation or ultrafiltration followed by quantitative determination by the colorimetric phenol-sulfuric acid method performed in glass tubes or in microplates. The content of polysaccharides was expressed as sucrose or pectin equivalents according to the standard curves of these standards. Results of the optimized gravimetric procedure were moderately repeatable. We demonstrated the linearity and appropriate repeatability of the phenol-sulfuric acid method in microplates but not in glass tubes. Thus, the method with ultrafiltration followed by phenol-sulfuric acid method in microplates had good repeatability, accuracy, and linearity. This simple method was shown to be useful for determining polysaccharides in herbal sirup.