Anticomplement and antitussive activities of major compound extracted from Chimonanthus nitens Oliv. Leaf.

The Chimonanthus nitens Oliv. leaf (CNOL), as a traditional Chinese medicine (TCM), has been widely used for the treatment of influenza and colds for a long history. However, the mechanism of colds and related the effects in CNOL have been little studied. In this study, anticomplement and antitussive activities of different polarity extracts of CNOL were evaluated. Ethyl acetate extract (EAE) among different extracts not only decreased significantly cough times by 21-58% (p < 0.01), but also had anticomplement effects which exhibited with the CH₅₀ values of 0.100 mg/mL. A total of 28 constituents (10 coumarins, 13 flavonoids and 5 phenolics) were identified in EAE based on the ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) technique. Eight compounds in EAE were evaluated by ammonia-induced cough model for their reveal the antitussive mechanisms and classical anticomplement pathway as well. The results indicated the antitussive effects of scopoletin, kaempferol-3-O-rutinoside and kaempferol may depend on central mechanisms and the flavonoids such as compounds of kaempferol-3-O-rutinoside and kaempferol have better anticomplementary activity than coumarins like compounds of scopolin, scopoletin and isofraxidin. Taken together, kaempferol-3-O-rutinoside and kaempferol could be important chemical markers in the present study which might be used to evaluate the quality and biological activity of CNOL.