Simultaneous determination of cryptotanshinone, tanshinone I and tanshinone IIA in traditional Chinese medicinal preparations containing Radix salvia miltiorrhiza by HPLC

A reversed-phase high performance liquid chromatographic method was established for the simultaneous determination of tanshinones in five kinds of traditional Chinese medicinal preparations (TCMPs) containing Radix salvia miltiorrhiza (Chinese herbal name: Danshen). Tanshinones including cryptotanshinone, tanshinone I and tanshinone IIA were successfully separated on a Diamonsil C18 column (150 mm x 4.6 mm i.d., 5 microm). The mobile phase was a mixture of methanol, tetrahydrofuran, water and glacial acetic acid (20:35:44:1, v/v/v/v), employing isocratic elution at a flow rate of 1.0 mL/min. Detection was accomplished at 254 nm. The compounds were identified by comparing their retention times and UV spectra in the 200-400 nm range with authentic standards. Regression equations revealed good linear relationship between the peak areas of the constituents and their concentrations (correlation coefficients: 0.9998 for cryptotanshinone, 0.9999 for tanshinone I and 1.0000 for tanshinone IIA). The relative standard deviations (n=6) of retention time and peak area were less than 0.25% and 1.00%, respectively. The recoveries were between 96.2% and 102.5%. The proposed method has been successfully applied to the simultaneous determination of the tanshinones in five kinds of Chinese herbal preparations containing Danshen within 20 min.