Miscellaneous Contributions to the Essential Oils of Plants from Various Territories. XLVIII. A Biochemical Study of the Essential Oils of Schizonepeta tenuifolia BRIQ.

Abstract

The seasonal variations in the essential oil of Schizonepeta tenuifolia BRIQ. (Labiatae, Japanese name, "Keigai") was studied. During the growing season, (-)-pulegone content decreased from 77.3 to 21.2%, (+)-menthone concentration varied from 11.1 to 61.5%. These changes of contents in the oils are similar to those of Mentha, namely toward the climax stage of vegetation, pulegone was gradually reduced to menthone. The essential oils of leaves, spikes, and stems were analyzed by using gas chromatography-mass spectrometry, and 43 constituents were positively identified, including 26 newly identified ones.