In vitro cultures were initiated using plants of Mentha viridis L. originating from Greece. The shoots tips were sterilised with chloramine-T (5% solution) for 25 minutes. The initiation medium was Murashige-Skoog (1962) (MS) enriched with various combinations of cytokinins and auxins. The main morphogenetic reaction of the inoculated explants (shoot tips and nodes) was neoplantlet regeneration. Shoot and root formation was inhibited only on medium formula comprising 2,4-D, that provided a cream-green friable callus, deprived of organogenetic capacity. MS medium with benzylaminopurine (BAP) and giberellic acid (GA) stimulated multiple shooting and (seldom) root formation. In vitro regenerants were transfered to septic medium and subsequently to experimental fields during 2004 and 2005. The regenerants (first and second year of vegetation) were submitted to biochemical tests in 2005. The best output for polyphenols and flavons was registered for the ethanolic extractions (both warm and cold, 70% ethanol). The quantities of this biologically active principles are similar to those of control plants. There are higher amounts of flavons and lower amounts of polyphenols compared to control. TLC qualitative analysis for triterpenes and phytosteroles (in warm ethanolic extractions) evinced the presence of ? sitosterole and of ursolic acid. The amount of volatile oils in control plants reaches 0.7% and was exceeded in case of vitroclones (3.33% for the first year regenerants and 4.00% in case of the second year regenerants). In vitro regenerants displayed a narrower range of volatile oil compounds. The amount of carvone was much higher (59.11 – 59.16%) compared to control (34.46%). The quantity of 2-cyclohexene-1-one is much lower in regenerants (0 – 1.65%) than in control plants (25.10%).
