Characterization of the chemical constituents of Croton crassifolius Geisel extract and plasma pharmacokinetics of 6 terpenoids after oral administration by UPLC-Q/TOF-MS.

Introduction: Croton crassifolius Geisel. (CCG) is a traditional Chinese medicine widely used in South China. It has various pharmacological effects and is often used in treating rheumatoid arthritis and gastric and duodenal ulcers. However, the chemical characteristics and its effective constituents are still scarcely studied.

Objective: To determine the phytochemical profile of the CCG extract and to investigate the chemical characteristics of terpenoids extracted from rat plasma following oral administration of CCG extract based on UPLC-Q/TOF-MS. Moreover, six terpenoids in CCG were quantified, and in vivo pharmacokinetic behavior after oral CCG extract was further explored.

Results: In total, 56 terpenoids were tentatively identified in the CCG extract and 16 terpenoids were detected in rat plasma after oral CCG extract. In addition, the contents of six terpenoids in CCG were clarified. The plasma quantification method of six terpenoids was further established, validated, and confirmed to have good sensitivity and specificity. The six analytes exhibited excellent linearity in respective concentration ranges (r ≥ 0.998). The intra-day and inter-day precisions relative standard deviation (RSD, %) were less than 11.27%, and the accuracies ranged from -7.06% to 9.91%. Stability, extraction recovery, and matrix effect in plasma were within the required limits (RSD < 15%).

Conclusion: A total of 56 terpenoids were identified in CCG and 16 prototype components in plasma after oral CCG. The validated quantitative method was successfully applied to the simultaneous determination of six major terpenoids in plasma. The pharmacokinetic parameters are clarified, which can guide the clinical application of CCG.