Comparative pharmacokinetic profiles of picrosides I and II from kutkin, Picrorhiza kurroa extract and its formulation in rats.

Picrosides I and II are the active chemical constituents, present in the roots and rhizomes of Picrorhiza kurroa Royle (family: Scrophulariaceae). The plant is ethnomedically claimed for the treatment of liver and upper respiratory tract infection, fever, dyspepsia and scorpion sting. This study attempts to determine the in vivo pharmacokinetic profile of picrosides I and II in rats after oral administration of three different preparations namely, kutkin (a mixture of picrosides I and II), P. kurroa extract and Picrolax® capsule (marketed formulation). A simple, precise, specific and sensitive method was developed for simultaneous quantification of picrosides I and II in rat plasma and was applied for the pharmacokinetic study. Pharmacokinetic parameters were calculated from the observed plasma concentration of picrosides I and II. The results showed a significant difference (p≤0.05) in oral bioavailability of picrosides I and II from different preparations. Both the compounds were found to be more bioavailable from P. kurroa extract followed by Picrolax® capsule and kutkin. Moreover, we also developed a novel method for isolation of kutkin from roots of P. kurroa with a high yield of 2.4% w/w. The information gained from this study provides a meaningful basis for clinical application and mechanistic study of such phytochemicals.