Microscopic evaluation and seasonal variations of anthraquinone glycosides of cultivated Cassia fistula Linn

Abstract

In this report, we present the results of the microscopy, seasonal variations and spectrophotometry estimation of hydroxy-anthraquinone glycosides of cultivated Cassia fistula Linn. The total glycoside contents of the morphological parts of this species at different stages of growth arc also presented. The study shows that anthraquinone glycosides are concentrated in the leaves (1.75%) and flowers (1.58%) at peak flowering. Notable seasonal variations were observed in the cultivated species. Hydroxyanthraquinones reached peak levels during the months of September (1.08%) and October (2.20%). There was a significant drop (P < 0.05) in glycoside content during most part of the rainy season. It has been established that anthraquinone glycosides, rather than the aglycones, arc the active forms and hence an estimation of the total glycoside content o f a sample is a reliable indication of biological activity. The advantages of using the natural anthraquinone laxative when the glycoside content is highest are discussed. The study has provided useful information on the best period for harvesting the morphological parts of C. fistula for drug development.