Quick and easy preparation method for decoctions of kampo formula (part 3): <scp>E</scp>xtraction efficiency of the <scp>IPCD</scp> method for volatile compounds

ABSTRACT Aim The immersing powdered crude drugs ( IPCD ) method was developed as a quick, easy and high‐yield way to prepare decoctions. IPCD may be very useful for decoctions of crude drugs containing volatile compounds because it does not involve boiling. The aim of this study was therefore to test this hypothesis using cinnamon bark (the bark of the trunk of C innamomum cassia ) and perilla herb (the leaves and the tips of the branches of P erilla frutescens var. acuta ). Methods The amounts of the marker compounds in the IPCD immersion prepared from cinnamon bark or perilla herb were measured and compared with those prepared with the conventional decoction method. Results The amounts of cinnamaldehyde and perillaldehyde in the IPCD immersion per 1 g of crude drugs exceeded those in the conventional decoctions by two‐fold and 30‐fold, respectively. Conclusion The IPCD method is outstanding for the decoction of crude drugs containing volatile compounds.