[GC-MS analysis of volatile oil from the ear of Schizonepeta tenifolia Briq].

Volatile oil was extracted from the ear of Schizonepeta tenifollia Briq. by supercritical carbon dioxide extraction and steam distillation, then GC-MS was used to analyse their components and determine the content. There were 41 components identified from products of supercritical carbon dioxide extraction, while 32 from those of steam distillation. The content of the main component, pulegone, was also different in the two extracts. It showed that the two extractions have differences in component and content to a certain extent.