LAUSR

The aim of the paper was the phytosociological study and its influence upon the biosynthesis of active compounds of two medicinal plants (Mentha piperita L. peppermint and Melissa officinalis L. lemon balm), which are widely used in phytotherapy. Our research was performed on dried leaves and the active substances content was determined by means of spectrophotometric (for evaluation of flavones, phenolcarboxylic acids and total phenolic contents) and volumetric methods (for evaluation of the essential oil content). Our results have shown that in the common (phytosociological) crops the active compounds are synthesized in higher amounts compared to the control crops. Moreover, for the common crops, horizontal and vertical development was much more obvious. In addition, our results regarding peppermint leaves, have shown that the active substances content have a different distribution throughout the day, with an upwards course during the morning and midday, whilst a descending direction was seen in the evening.