Systematically identifying the anti-inflammatory constituents of Cimicifuga dahurica by UPLC-Q/TOF-MS combined with network pharmacology analysis

Cimicifuga dahurica (Turcz.) Maxim, which is also regarded as the main origin of "Shengma" in the Chinese Pharmacopoeia, has been used as a cooling and detoxification agent for thousands of years. Our previous phytochemical investigations of C. dahurica extracts (CDEs) led to the isolation of a series of 9,19-cycloalkane triterpenoids and phenolic acids showing a potential anti-inflammatory activity. However, the chemical profiling of CDEs and the material basis of its anti-inflammatory effect in vivo has not been clarified. In the present study, the CDE chemical profile and prototype components in rat plasma were identified via ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. As a result, a total of 106 components were identified or tentatively characterized in CDEs, including 54 triterpenoids, 35 phenolic acids, eight amides and nine other type constituents (39 compounds were confirmed with the reference standards). In addition, 20 prototype components (15 triterpenoids and five phenolic acids) were identified in rat plasma, which potentially related to the anti-inflammatory effects of CDEs. Moreover, the anti-inflammatory activities of the main prototype components were further evaluated by their inhibitory effects on the production of NO, as well as the expressions of iNOS and COX-2 in lipopolysaccharide-stimulated RAW264.7 cells, which indicated that 9,19-cycloalkane triterpenoids may play an anti-inflammatory role by down-regulating the expression of iNOS.