Comparison of the Pharmacokinetic Profiles of a Standardized Extract of Centella asiatica and A Mixture of Madecassoside and Asiaticoside in Rats

Centella asiatica is a tropical plant commonly used as an herbal remedy in traditional medicines in many countries. In an attempt to establish an herbal extract with well-defined characteristics, a standardized extract of C . Asiatica , ECa 233, was developed. This extract contains at least 80% triterpenoid glycosides with the major constituents madecassoside and asiaticoside at a ratio of 1.5±0.5:1. In the present study, comparative pharmacokinetics of ECa 233 with its mixture of madecassoside and asiaticoside were conducted in rats. Following intravenous or oral administration of the test compounds, blood, tissues, urine, and feces were collected for the determination of madecassoside, asiaticoside, and their metabolite levels using liquid chromatography tandem mass spectrometry. Plasma levels of madecassoside and asiaticoside in the ECa 233-treated group were found to be higher than their respective counterparts in the mixture. Madecassoside and asiaticoside in both test formulae appeared to be widely distributed in several organs, and more than 50% of the administered doses were recovered as madecassic acid and asiatic acid in the feces within 24 to 48 h. The results clearly demonstrated the pharmacokinetic advantage of a standardized extract of C. Asiatica , ECa 233, compared with a mixture of madecassoside and asiaticoside at an equivalent amount. Other minor constituents that naturally exist in ECa 233 appeared to positively modulate the pharmacokinetics of its major constituents, resulting in relatively better pharmacokinetic profiles than those from a mixture of pure compounds.