Galactomannans (GM), a group of neutral nontoxic polysaccharides naturally occurring in the seeds of some legumes, are used in the textile, pharmaceutical, biomedical, cosmetics and food industries. As to date there are no documented reports on determination of the sugar composition in polysaccharides by HPTLC and the following study is an attempt in this direction. GM from seeds of Caesalpinia pulcherrima L. (CP) was isolated and purified by precipitation method using alcohol. A new, simple, sensitive, selective, precise, and robust HPTLC method for analysis of monosaccharides such as galactose, mannose, xylose and glucose in isolated CP GM has been developed and validated. Chromatograms were developed using a mobile phase of acetone: water (9:1 v/v) on pre-coated plate of silica gel GF aluminium TLC plate and quantified by UV spectrophotometer at 254nm. The Rf values were 0.45, 0.34, 0.40 and 0.60 for mannose, galactose, xylose and glucose, respectively. The linearity of method was found to be within the concentration range of 2000-10000 ng/spot for all above monosaccharides. The limit of detection for mannose, galactose, xylose and glucose was found to be 0.14986 ng/spot, 0.31973 ng/spot, 0.27569 ng/spot, and 0.36808 ng/spot, respectively. The limit of quantification for mannose, galactose, xylose and glucose was found to be 1.498 ng/spot, 3.197 ng/spot, 2.756 ng/spot, and 3.680 ng/spot, respectively. The method was also validated for precision, specificity and recovery. This developed method was used to analyze CP GM for monosaccharides compositions.

Keywords: HPTLC, Galactomannans, Monosaccharides, Caesalpinia pulcherrima