Chemical and Morphometrical Comparison Between two Peppermint Notomorphs.

Flowers and leaves were collected for the comparison of the trichome morphometrical data and the oil chemical data between two peppermint notomorphs ( PALLESCENS and RUBESCENS Camus). The counting of the glandular trichomes was undertaken by means of scanning electron microscope (SEM) and the averages were analyzed for variation (F-ratio). The two plants showed differences in density and number of trichomes, superior values being obtained by the M. RUBESCENS notomorph. The leaves showed a positive correlation between the number of trichomes and the oil yielded. The oil, analyzed using GC-MS coupling, showed high percentages of menthol (53.76) in the leaves and of menthol (36.65), menthone (19.71) and menthofuran (17.70) in the M. RUBESCENS flowers. The M. PALLESCENS notomorph showed high percentages of menthyl acetate (28.86) and moderate percentages of menthol (25.75) in the leaves, while in the flowers menthofuran with 21.10% gave the highest value.