The natural variation of the pulegone content in various oils of peppermint

Abstract A total of 375 samples of American peppermint oil from three consecutive crops 1977–1979 grown in Eastern Oregon USA were analysed by gas‐liquid chromatography (g.l.c). The pulegone content showed large variations in samples from different fields. This variation in percentage pulegone composition was shown to be directly related to the harvest date. The pulegone content of first year mint normally harvested at the end of the season was found to be very low when compared to older mints harvested earlier, and to other commercially available peppermint oils from various countries of origin. The pulegone content of the commercially available samples showed large variation with origin.