Quantitative Densitometric Evaluation of Harpagoside in the Secondary Roots of Harpagophytum procumbens D.C.

Harpagophytum procumbens D.C. (Devil's Claw) secondary roots are used in Europe as a home remedy for lack of appetite, dyspeptic complaints, and in supportive therapy for degenerative disorders of the locomotor system. The main characteristic iridoid glucoside of the plant is harapagoside. An HPTLC method has been developed for the quantitative determination of harpagoside in the secondary roots and extracts of this plant. The mobile phase used is an optimized version of one described in the literature.It furnished the most homogenous spots for quantitative densitometric evaluation ( at lambda= 286 nm, the wavelenght of maximum absorption for harapgoside).The results have been compared with those obtained afetr visualization with sulfuric acid-vanillin reagent and those obtained using a previously published HPLC method; To check that separation was complete, the spectra of harpagoside obtained from Devil's Claw extracts before and after visualization were superimposed on thos of harpagoside standard.