Antipruritic Effects of the Supercritical Fluid Extract from Cnidii monnieri fructus (dried fruits of Cnidium monnieri Cusson) in Mice

摘要

Antipruritic effects of a CO_2 supercritical fluid extract (SFE) of Cnidii monnieri fructus (CM-SFE; dried fruit of Cnidium monnieri CUSSON) were evaluated in mice and compared with a 70% ethanol-extract from Cnidii monnieri fructus (CM-EtOH). Thirty min after p.o. administration of CM-SFE (10, 20， 50,100 mg/kg) or CM-EtOH (100， 20O, 500 mg/kg), histamine or serotonin (5-HT,100 nmol/20 mul/site) was administered intradermally into the rostral back, and the number of scratch bouts in 60 min was counted in each mouse. CM-SFE inhibited the scratching behavior induced by both histamine and 5-HT in a dose dependent manner, whereas CM-EtOH inhibited these chemical mediator-induced scratching responses only at high doses and were accompanied by toxicity-like symptoms. In addition, CM-SFE inhibited histamine-induced vascular hyperpermeability in proportion to the administered dose; CM-EtOH also inhibited hyperpermeability, but its effect leveled off at doses of approximately 200 mg/kg. Quantitative analysis showed high concentrations of osthole and imperatorin, indicating that these coumarin derivatives contained in CM were present in CM-SFE, These results suggest that CM-SFE contains components that are more active in suppressing histamine- and 5-HT-induced itch-scratch responses than does CM-EtOH, and the antipruritic effects of CM-SFE may be caused by the synergistic action of osthole and imperatorin. The results show that SFE may be a useful method for obtaining antipruritogenic extracts from Cnidii monnieri fructus.