Determination of madecassoside and asiaticoside contents of C. asiatica leaf and C. asiatica-containing ointment and dentifrice by HPLC-coupled pulsed amperometric detection

The present study reports the development and application of an HPLC-coupled pulsed amperometric detection method to determine the madecassoside and asiaticoside contents of Centella asiatica leaf and of commercial C. asiatica-containing ointment and dentifrice. C. asiatica, which was not pretreated, was extracted with 50% ethanol for 10 min. Madecassoside and asiaticoside were separated on a C18 column within 5 min using 25% (v/v) acetonitrile as the mobile phase. Both compounds were detected with high sensitivity when sodium hydroxide was used as a post-column eluent. Madecassoside and asiaticoside both displayed limits of detection of 0.005 μg/mL and linear regression coefficients of 0.9994 and 1.0000, respectively. The intra- and inter-day precisions were < 8.85% and average recovery was > 94.79%. The madecassoside and asiaticoside contents of ointment and dentifrice were successfully determined without sample purification or concentration owing to the high method sensitivity and selectivity.