Spearmint oil

Spearmint oils are obtained by steam distillation of the flowering herbs of Mentha spicata L. ssp. spicata (native spearmint; in China and India also from other varieties) andMentha x gracilis Sole (syn.Mentha cardiaca Ger., Scotch spearmint). They are colorless to yellow-green liquids with a fresh, caraway, minty odor.
d²⁰₂₀ 0.921–0.938; n²⁰_D 1.484–1.491; α²⁰_D ?59 ° to ?48 °; solubility: 1 vol in ≤3 vol of 70% ethanol at 20 °C; carbonyl number: ≥224, corresponding to a carvone content of 60%.
The main producer of spearmint oil is the United States, primarily the state of Washington. Smaller amounts are also produced in some Midwest states and Canada.
Total annual North American production is ～1200 t, 30–50% being of the native type and 50–70% of the Scotch type. Other cultivation areas for spearmint oils exist in China and India (together ～800 t), where oils of a native type are produced with very similar compositions to the US oils. Oils with a higher carvone content are obtained by redistillation.
By far, spearmint oil is themost used for flavoring toothpaste and chewing gum. Smaller quantities are used in other oral care products and in pharmaceutical preparations.

The oil is a colorless, pale-yellow to greenish-yellow liquid. It may be rectified by distillation.

spearmint oil (Mentha viridis) is a cooling, aromatic stimulant described as having cleansing and decongesting properties. It is also astringent, and can add fragrance while helping mask odor. Its use is indicated for acne and oily skin. Its fragrance and therapeutic activity is similar to that of peppermint but fresher and less harsh.

The oil contains α-pinene, α-phellandrene, l-limonene, octyl alcohol, dipentene cineol (in some varieties only), dihydrocarveol and carvone. Esters of acetic butyric and caproic acids are also reported present in the oil.

Mildly toxic by ingestion. Mutation data reported. A skin irritant and an allergen. When heated to decomposition it emits acrid smoke and irritating fumes. Used as a flavoring agent.