Seasonal accumulation of anthraquinones in leaves of cultivated Cassia podocarpa Guill et Perr.

Seasonal variations and spectrophotometric determination of anthraquinones in cultivated Cassia podocarpa are presented. The study shows that combined anthraquinones are concentrated in the leaves at peak flowering (2.43%) and lowest in the bark (0.21%). Anthraquinone glycosides reached peak levels during the months of October to March (dry season), the maximum being recorded during January to March. There was significant drop in glycosidic content during the period April to September (rainy season). There was slight increase in concentration of aglycones during the rainy season which may be due to inter-conversion of some glycosides to the aglycones. However, the free aglycone content is much lower than the glycosides. This is desirable for optimum laxative activity and reduced toxicity. This study is significant because it provides useful information on the seasonal distribution of anthraquinones and the best period for harvesting leaves of C. podocarpa for drug development. The inclusion of C. podocarpa in the African Pharmacopoeia will, no doubt, enhance its commercialization as laxative and for its antimicrobial effect.