Table: Essential Oil Components of Two Commonly Used Species of Asarum Used as a Source of Xi Xin.
Each of these herbs has about 2.5% essential oil, and the figures shown are the proportions of that oil (6). A dash (-) indicates that the content is relatively low, less than 1% each. According to Japanese studies (8), the essential oil content can vary markedly, depending on growing conditions, so these figures should be considered as only one example of the distribution of amounts of component ingredients.
Essential Oil Content A. heterotropoides A. sieboldii
methyl eugenol 51.6% 42.4%
safrole 12.0% -
eucarvone 9.8% -
sabinene 3.8% -
elemicin 3.4% -
estragole 1.9% -
croweacin - 14.5%
asaricin - 9.3%
beta-pinene 1.1% 2.8%
alpha-terpineol - 2.6%
others 27.4% 28.4%http://www.itmonline.org/pdf/asarum.pdf (http://www.itmonline.org/pdf/asarum.pdf)