Phytochemical screening of Kenyan rumex species as a possible source of purgatives

Abstract

Rumex species have been widely used around the world for anthelmintic and laxative purposes. In this country R. abyssinicus, R. bequaertii and R. usambarensis are reputed as useful for the same purposes in traditional medicine. Along with R. ruwenzorensis they complete the list of this genus of polygonaceae family which are indigenous to Kenya. Another species growing here but was introduced only recently is R. crispus which is a native of America and Euroasian continents. Its distribution here is still restricted to the areas around Nairobi and Molo towns. In this work, on the indigenous Rumex species, the roots, stems and leaves, and seeds were surveyed for existence of various secondary metabolites. Only the roots of R. crispus were surveyed for these compounds. Anthraquinones and their glycosides are established to have anthelmintic and laxative activity in human alimentary canal (Fairbairn; 1949) . The ground powders of the parts of the plants were subjected to successive extraction fractionation in a soxhlet with the solvents, petroleum ether, chloroform and methanol. The first two fractions were usually combined and subjected to silica gel chromatography to separate the orange pigments.