ANALYSIS AND DISTRIBUTION OF FLAVONOID GLYCOSIDES AND ROSMARINIC ACID IN 40 MENTHA X PIPERITA CLONES

A reversed-phase high-performance liquid chromatographic method has been developed for the qualitative and quantitative analysis of a caffeic acid derivative, rosmarinic acid, and the main flavone and flavanone glycosides in leaves of Mentha x piperita, namely eriocitrin, luteolin 7-O-rutinoside, hesperidin, isorhoifolin, diosmin, eriodictyol 7-O-glucoside, and narirutin. The last two were identified for the first time in M. x piperita and Mentha genus, respectively. Forty clones, belonging to the three varieties of M. X piperita, were investigated. The eight phenolic constituents are present in all clones. The flavonoid content of the leaves ranged from 8.6 to 17.8% on dry weight basis. In all instances, eriocitrin, with a concentration range of 6.6-15.0%, is the dominant flavonoid glycoside accompanied by an appreciable amount of luteolin 7-O-rutinoside, hesperidin, and rosmarinic acid. The chemotaxonomic and therapeutic relevances of these results are discussed.