Simultaneous Determination of Seven Active Compounds in Radix Salviae Miltiorrhizae by Temperature-Controlled Ultrasound-Assisted Extraction and HPLC

A simple and effective high-performance liquid chromatographic (HPLC) method has been developed for simultaneous quantification of three phenolic acids (3,4-dihydroxyphenyllactic acid (Chinese name danshensu), protocatechuic aldehyde, and salvianolic acid B) and four diterpenes (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone II_A) in radix salviae miltiorrhizae. Chromatography was performed on a 250 mm × 4.6 mm i.d., 5-μm particle size, C₁₈ column. The mobile phase was a linear gradient prepared from 0.1% (v/v) aqueous formic acid and acetonitrile at a flow-rate of 1.0 mL min⁻¹. All the target components were well separated with high resolution and without interference. Good linearity (R ² > 0.999) was observed over the concentration ranges investigated, and intra-day and inter-day precision were high. Temperature-controlled ultrasound-assisted extraction was used to prevent hydrolysis of thermally unstable components during the sample-extraction procedure, and the extraction conditions were carefully optimized. Recovery of the seven components was from 98.45 to 100.63% and relative standard deviations were always <1.5%. The validated method was successfully used for simultaneous quantification of the three phenolic acids and the four diterpenes in radix salviae miltiorrhizae of different geographic origins.