Determination of Perilla ketone in Perilla Herb by capillary gas chromatography/mass spectrometry.

Abstract

Perilla ketone (PK), a potent lung toxin, in Perilla Herb was determined by capillary gas chromatography/mass spectrometory (capillary GC-MS). Without any cleanup, PK in ethyl acetate extract from a Perilla Herb sample was well separated by using a middle polar fused silica column (DB-17), and for the identification, mass chromatography monitoring m/z 166 from the molecular ion and m/z 110 and 95 from the fragment ions was carried out under an E.I. condition. Selective ion monitoring (SIM) of the both McLafferty rearrangement peaks, m/z 110 from PK and 112 from menthone added as an internal standard, allows sensitive and accurate quantification. The calibration curve was rectilinear in the range from 0.005 ng to 10 ng with the identification limit of 0.001 ng. The average recovery was 97.6% for PK added to Perilla Herb at the level of 300μg/500 mg. By this method, crude drugs on the market were analyzed : PK detected from 9 out of 25 samples (36%), and the amounts of PK ranged from 1.1 to 119.9 mg/100 g. It turned out that the PK doses taken in a day are less than 1/104-1/103 levels of LD50 to the mice.