Mentha oil is obtained by steam distillation of the fresh flowering tops of the plants known as Mentha piperita Linn; and Mentha arvensis varpiperascens (Japanese Mint (Family: Labiatae).
Mentha oil are colourless or pale yellow liquid; a strong and penetrating odour and taste is pungent and sensation of a cool feeling when air is drawn into the mouth.
Mentha oil contains chiefly l-menthol to the extent of 70% in free, as well as, in the form of esters, depending upon variety (like American, Japanese, Indian).
American mentha oil contains 80% menthol while Japanese oil contains 70–90%.
Other important constituents of peppermint oil are menthone, menthofuran, Jasmone, menthyl isovalerate, menthyl acetate, and several other terpenes derivatives.
The other terpene includes 1-limonene, isopulegone, cineole, pinene, camphene, etc.,
Jasmone and esters are responsible for pleasant flavour, while menthofuran causes resinilication and develops dirty smell.
