ABSTRACT
Crude drugs that feature the name “gui” have appeared in classical medicinal textbooks with different names,and the correspondence between their names and origins remains the subject of research and discussion. In the present study, we investigated these correspondences using the descriptions in the annotations of the Bencaojingjizhu and through our previous study that revealed the standards of weights and measures in this book. Based on this investigation, we strongly speculate that “gui” in the Bencaojingjizhu was the branch skin of Cinnamomum cassia (C. cassia) (corresponding to cinnamon sticks in the market), which fits with the descriptions about the length and weight of “gui” -related crude drugs in this book. We measured the contents of cinnamic aldehyde and coumarin in the branch skin of C. cassia, and compared these to contents in other crude drugs related to “gui” that can be obtained on the market. The contents of these two compounds in the branch skin of C. cassia were similar to those in the bark of C. cassia from Vietnam that meets the standards for cinnamon bark in the Japanese Pharmacopoeia and is regarded as high-grade in the market. These results support our speculation, and it might be possible that the branch skin of C. cassia can be used as medicine instead of cinnamon bark.