The Effect of Different Drying Methods on Contents of Iridoid Glycosides in Rehmannia glutinosa Libosch. and Scrophularia ningpoensis Hessl

Objective To investigate the effect of different drying methods on contents of iridoid glycosides in Rehmannia glutinosa Libosch and Scrophularia ningpoensis Hessl.Methods After vacuum torrafaction and commonl torrefaction in 1,3,5,7,9 h,both at 105℃,the content of catalpol in Radix Rehmanniae and harpagoside in Scrophularia ningpoensis Hessl.was detected by high performance liquid chromatography.Results Compared with untreated group,the content of the catalpol in Rehmannia glutinosa Libosch.decreased by 60% and harpagoside in Scrophularia ningpoensis Hessl.dropped by 80% treated with common torrefaction.No clear change was observed in the contents in vacuum torrafaction.Conclusion Vacuum torrafaction is a better drying methods for iridoid glycosides.