Determination of Cryptotanshinone, Tanshinone I, and Tanshinone IIA in Salvia Miltiorrhiza by Micro HPLC with Amperometric Detection

Abstract

A highly sensitive and simple method for determining cryptotanshinone (Cry), tanshinone I (Tan I), and tanshinone IIA (Tan IIA) in Salvia miltiorrhiza was developed using micro HPLC with electrochemical detection (µHPLC-ED). The tanshinones were extracted using an ultrasonic method, with methanol as the extractant. The separation was carried out on a C18 (150 mm × 1.0 mm i.d., 3 µm particle size) analytical column. The mobile phase was acetonitrile-water-formic acid mixture (52:48:0.6, v/v/v) solution. The flow rate and the temperature of the column were set at 30 µL/min and 35°C. The applied potential was set at −0.4 V vs. Ag/AgCl. The peak heights for Cry, Tan I, and Tan IIA were found to be linearly related to the amounts injected, ranging from 0.145 µmol/L to 3.88 µmol/L, 0.226 µmol/L to 3.01 µmol/L, and 0.149 µmol/L to 3.98 µmol/L, respectively. The RSD values of intra-day precision and repeatability were not more than 3.0%, and the recovery of three analytes were ranged from 96.7% to 97.5%. The results of the method validation indicated that this method had good precision and accuracy. As such, the method was applied to analyze crude materials and decoction pieces of Salvia miltiorrhiza.

Keywords:

• Cryptotanshinone
• Electrochemical detection
• Salvia miltiorrhiza
• Tanshinone I
• Tanshinone IIA

Acknowledgments

This work was supported in part by the Grants-in-Aid for Scientific Research (No. 21550089 to FK and No. 23591326 to HH) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. Xianchun Chen is a visiting researcher of an international exchange program between the China Academy of Chinese Medical Science and the School of Pharmacy, Tokyo University of Pharmacy and Life Sciences.

Notes

Note: Linearity was obtained by injecting six mixed standard solution with different concentrations. X, concentration of standard solution (µmol/L); Y, Mean peak current height (nA). The values of LOD and LOQ were described as the quantity of the analytes per injection.

Note: LOD was calculated by signal/noise = 3 and described as the quantity of the analyte per injection.

Note: *Content means the content of each analyte in S. miltiorrhiza (batch 1), which was calculated by using the external standard method.

The samples of batches 1–6 were bought in China; the sample of batch 7 was bought in Japan.

Content means the content of each analyte in S. miltiorrhiza, which was calculated by using the external standard method.

^a This batch of samples was crude material.

^b This batch of samples was decoction pieces.