Chemical composition of essential oils of two Mentha species

Abstract

the order of the retention indices. Twenty compounds were identified in M. vagans Boriss., which represented 97.1% of the oil. The oil consisted mainly of five oxygenated monoterpenes (83.4%), seven monoterpene hydrocarbons (8.7%), four sesquiterpene hydrocarbons (1.7%), and three oxygenated sesquiterpenes (3.1%). The main components were piperitenone oxide (68.5%), 1,8-cineole (13.5%),-myrcene (2.1%), caryophyllene oxide (2.0%), and -pinene (2.0%). In M. dahurica Fisch., twenty-four compounds representing 94.2% of the total oil were identified. The most abundant components were oxygenated monoterpenes (67.9%) and monoterpene hydrocarbons (29.3%). Piperitenone oxide (52.7%), -terpinene (8.5%), terpine-4-ol (6.4%), 1,8-cineole (4.8%), and -myrcene (4.5%) were the major components. The highest content of these two Mentha species is piperitenone oxide, which has been previously reported as the main component of the essential oils of M. spicata Linn. [9], M. rotundifolia Huds. [10], Calamintha nepeta subsp. glandulosa [11], and Tagetes erecta Linn. [12]. Plant Material. The aerial parts of M. vagans Boriss. were collected from Xinjiang area of China in June 2008, and the aerial parts of M. dahurica Fisch. were collected from Jiling area of China in June 2007, during the flowering period. Plant materials were taken immediately to the laboratory to be dried at ambient temperature. Voucher specimens were deposited in the Herbarium of the Botanical Institute of Jiangsu Province and the Chinese Academy of Sciences. Essential Oil Isolation. Air-dried plant materials were subjected to hydrodistillation using a Clevenger-type apparatus for 3 h. The obtained essential oils were dried over anhydrous sodium sulfate and, after filtration, stored in sealed vials under refrigeration until tested and analyzed. GC Analysis. GC analysis was performed on a Shimadzu 2010 gas chromatograph equipped with a DB-1 silica column (30 m 0.25 mm, film thickness 0.25 m). Nitrogen was used as carrier gas (1.0 mL/min). Injector and detector(FID) temperatures were kept at 250C and 280C, respectively. The oven temperature program was as follows: initial temperature 60C, held for 3 min and then increased at 3C/min to 240C, and kept at this temperature for 10 min. The split ratio was kept