Abstract
Nepeta sibirica L. has been used for the treatment of various diseases and is one of the traditional medicines of Mongolia. The essential oil of N. sibirica was shown to contain a single component by gas chromatography–mass spectrometry (GC–MS) analysis. The optical rotation and nuclear magnetic resonance (NMR) analyses demonstrated that the component was 4aα,7α,7aα-nepetalactone. This essential oil, that is, 4aα,7α,7aα-nepetalactone, showed antimicrobial activity against Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus fumigatus. Cell cytotoxicity testing showed that the nepetalactone was cytotoxic to HL60 myeloma and Kato III stomach carcinoma cell lines. The essential oil of this Mongolian N. sibirica is useful for researching the bioactivity of nepetalactone, which has been difficult to prepare.