Integrating multiple-chromatographic approaches to evaluate chemical consistency of Chang-Kang-Fang preparations from mixed-herb decoction and combined single-herb decoction

Chang-Kang-Fang formula (CKF), a multi-herbs traditional Chinese medicine (TCM) prescription for treating irritable bowel syndrome (IBS), has been clinically applied in the traditional form of mixed-herb decoction (MHD), or in the modern form of combined single-herb decoction (cSHD, so called dispensing granule decoction) in the near decades, but the chemical consistency between the MHD and cSHD is still unknown. Herein, a new strategy by integrating multiple-chromatographic approaches to characterize both polysaccharides and small molecules was developed to compare the chemical consistency between MHD and cSHD. Sixteen small molecules were simultaneously qualified and quantified by UPLC-QTOF-MS/MS, the molecular weight distribution of polysaccharides was characterized by HPGPC-ELSD, while the monosaccharide composition and total saccharides content were determined by HPLC-PDA and UV-VIS, respectively. It was found that the molecular weight range and monosaccharide composition of polysaccharides, as well as the composition of small molecules, were identical between MHD and cSHD. However, the contents of berberine, epiberberine, coptisine, palmatine, albiflorin and paeoniflorin in MHD were significantly lower than those in cSHD, whereas the content of polysaccharides in MHD was higher than that in cSHD, indicating that there is a significant difference in the quality between MHD and cSHD, in particular for the relative contents of major small molecules and polysaccharides. Whether or not these quality variations affect the efficacy and safety of CKF deserves further investigation.