COMPARATIVE CHARACTERIZATION OF TEN AROMATIC ACIDS IN SIWU SERIES DECOCTIONS AND THEIR CONSTITUTING HERBS BY HPLC-DAD METHOD

Abstract

A high performance liquid chromatographic method with diode array detection (DAD) was established for simultaneous determination of ten aromatic acids in five Siwu series decoctions (Xiongqiong decoction, Siwu decoction, Taohongsiwu decoction, Xiangfusiwu decoction, and Shaofuzhuyu decoction) and related 16 crude herbs. These ten compounds were analyzed simultaneously with a SunFire C₁₈ column (4.6 mm × 250 mm, 5 µm) by gradient elution using 0.5% aqueous acetate acid (v/v)-methanol as the mobile phase; the flow rate was 1.0 mL/min. The sample was detected with DAD at 230, 254, and 323 nm and the column was maintained at 25°C. All the compounds showed good linearity (r² > 0.9998) in the range of the test concentration. The precisions were evaluated by intra-day and inter-day tests, and relative standard deviation (RSD) values were reported within the range of 0.23–2.28% and 0.26–2.79%. The recovery studies for the quantified compounds were observed over the range of 94.8% and 104.6% with RSD values less than 3.29%. The validated method was successfully applied for the simultaneous determination of the aromatic acids contents in five formulae and 16 crude herbs, and some aromatic acids were identified for the first time in these crude herbs. The results also indicated that the contents of some aromatic acids varied greatly in different decocting process. This research provided some experimental data reference for clinical application of the relative herbs, and it could enhance the study of the compatibility rule of traditional Chinese medicine.

Keywords:

• aromatic acid
• comparative characterization
• derived formulae
• high performance liquid chromatography
• quantitative analysis
• siwu decoction

Notes

^a SWD, Siwu decoction; XQD, Xiongqiong decoction; THSWD, Taohongsiwu decoction; XFSWD, Xiangfusiwu decoction; SFZYD, Shaofuzhuyu decoction.

a−, not reported in this herb.

b+, reported in this herb.

^a y = Ax + B; y is peak area; x is concentration of the reference compounds (µg/mL).

^b r²is the correlation coefficient of the equation.

^c LOD is the limit of detection.

^d LOQ is the limit of quantification.

–, not detected.

^a MC: contents of co-boiled formulae were measured.

^b CC: contents of single boiled crude drugs were calculated by proportion of every formula.

^c –, not detected.