Investigating Changes in Pharmacokinetics of Steroidal Alkaloids from a Hydroethanolic Fritillariae thunbergii Bulbus Extract in 2,4-Dinitrobenzene Sulfonic Acid-Induced Colitis Rats.

Fritillariae thunbergii Bulbus (FTB), a member of the Liliaceae family, has a long history of use in many herbal formulations for traditional and modern clinical applications to treat various infections and inflammation. To understand FTB's diverse physiochemical properties, it is important to determine the pharmacokinetic properties of its active constituents, the steroidal alkaloids. The aim of the present study was to investigate the pharmacokinetic alterations of the alkaloids, the active components of FTB, in the presence of colitis. A single oral dose of FTB (1 g/kg) was treated to a 2,4-dinitrobenzene sulfonic acid (DNBS)-induced colitis rat model to assess whether the colitis condition could influence the pharmacokinetics of the major alkaloids present in FTB. Among the four major alkaloids, peimisine exhibited a significantly increased systemic exposure, approximately five times higher, under the colitis condition compared with the normal state. Meanwhile, peimine, peiminine, and sipeimine exhibited shorter half-lives in the DNBS group without significant changes in systemic absorption. As herbal medicine may contain active substances with different or opposing efficacies, careful consideration of pharmacokinetic changes in individual components due to diseases is necessary. Further experiments on peimisine are required to ensure the effectiveness and safety of FTB's clinical application in the presence of colitis.