The mint oils could in a way be regarded as standardized products because oils from different sources are mixed to meet composition requirements set by the International Standardization Organisation (ISO) or by different pharmacopoeias. For instance, the European pharmacopoeia sets the following requirements for the composition of peppermint oil: limonene 1.0-5.0%, cineole 3.5-14.0%, menthone 14.0-32.0%, menthofuran 1.09.0%, isomenthone 1.5-10.0%, menthyl acetate 2.8-10.0%, menthol 30.055.0%, pulegone not more than 4.0%, and carvone not more than 1.0%. In addition, the ratio of cineole content to limonene content is to be greater that 2 (3). Menthol may be produced by freezing cornmint oil, which gives the pure (—)-enantiomer plus dementholized oil, which is utilized to flavor toothpastes and chewing gum. Menthol can also be produced by semisyn-thesis starting from pinene or by total synthesis, which yields racemic menthol. Menthol is largely consumed by the tobacco industry and by the pharmaceutical industry in itch-relieving creams, cough mixtures, and preparations to relieve the symptoms of the common cold (2).
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