Individual Monitoring to Study Organ and Diurnal Variations in Mentha longifolia L.

Growing aromatic  plants as a  source of bioactive compounds  and extracts requires the production of raw  materials with a standardized chemical composition. For this purpose, besides the selection of most suitable chemotypes, organ variations and phenotypic plasticity should be taken into account. The aim of this work is to carry out a first approach to diurnal variation for leaves and inflorescences in Mentha longifolia L. by means of individual monitoring as a way to bear in mind the intrapopulational variability. A total amount of 36 samples were processed from 3 individuals that were monitored during two days with different meteorological conditions. The extraction was performed by means of an ultrasound assisted method at low temperature in order to avoid the formation of artifacts. Two individuals showed a-terpineol acetate and carvone acetate as major compounds. No organ and diurnal variations were observed in neither of both individuals. Pulegone was found the major compound in the third individual, alt hough considerable amounts of 1,8-cineole, isomenthone, trans-isopulegone, carvone acetate (only in inflorescences) and sesquiterpenes were also observed. Some great changes affecting major compounds were registered in this individual, both regarding organ differences and diurnal variations. Nevertheless, the most noteworthy result was the differences found related to meteorological conditions. This way, hot and dry periods could have a different and relevant influence on volatile chemical profile according to the M. longifolia chemotype.