Comparison of Pulsatilla decoction formula granules versus its standard decoction for consistency of chemical components and bioequivalence in mice with ulcerative colitis

To investigate the consistency of chemical composition between commercially available formula granules (FG) and standard decoction (SD) of Pulsatilla Decoction and their pharmacodynamic effects in mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC).

Ultra-high performance liquid chromatography coupled with Fourier transform electrostatic field orbitrap high-resolution mass spectrometry (UHPLC-Orbitrap HRMS) combined with mzCloud database and analyisis of literature and reference substances was used to compare the chemical profiles and major components of the two preparations, whose fingerprints and index components were determined with HPLC. Chemical components consistency of the two preparations was assessed by evaluating the number and total area of common peaks, fingerprint similarity, extraction rate, and index component contents. A mouse model of DSS-induced UC was used to to compare the therapeutic effects of the two preparations.

Chemical composition analysis showed basically consistent number and retention times of chromatographic peaks of FG and SD in both positive and negative ion modes with only differences in response intensity, and identified a total of 39 major components. FG and SD showed identical fingerprint common peaks with a similarity >0.99. Compared with SD, FG exhibited significantly higher relative total common peak area ratios (1.24, 1.34, and 1.20), a higher mean extraction rate (18.09% vs 13.71%), higher pulchinenoside B₅ and jatrorrhizine contents, but lower obaculactone content with comparable contents of the other 10 components. In the UC mouse models, FG and SD showed similar therapeutic effects and both significantly ameliorated macroscopic signs, promoted colonic tissue repaire, increased anti-inflammatory and decreased pro-inflammatory cytokines, and enhanced mucosal barrier protein expression.

Pulsatilla Decoction SD and FG have basically consistent chemical composition with only minor differences and show pharmacodynamic equivalence in mice with DSS-induced UC.