Oils, horsemint

Description

Various odorous erect herbs approximately 30 to 90 cm (12 to 35 in.) tall, Monarda punctata has toothed leaves and large, yellow or white flowers clustered in a few verticles surrounded by bracts. It has petioled, lanceolate leaves narrowing at the base and a nearly smooth corolla, yellowish with the upper lip spotted purple. The plant grows wild in the United States and is used for the extraction of thymol. The whole plant is used. Horsemint has a harsh, burning aromatic flavor and a thymol-like odor.
The essential oil is obtained by distillation of the freshly cut or partially dried herb in approximately 1% and 3% yields, respectively. The oil is a yellowish-red to brown liquid with an odor reminiscent of thymol. Its specific gravity at 20°C is 0.930 to 0.940.
On standing, the oil deposits large crystals of thymol (44 to 61% of the oil). Its main constituents include carvacrol, traces of limonene, and thymol hydroquionone. Other Monarda varieties also growing in the United States-M. fistulosa, M. didyma, and others-contain much less thymol.
The derivative is fluid extract.

Chemical properties

See Horsemint