In vitro multiplication of Mentha piperita L. and comparative evaluation of some biochemical compounds in plants regenerated by micropropagation and conventional method

The aim of this study was to elaborate an efficient in vitro multiplication protocol for Mentha piperita L. (peppermint) and to perform a comparative evaluation of some biochemical compounds in plants regenerated by micropropagation and conventional method. The use of a plain Murashige and Skoog (MS) basal medium favored the induction of regenerative processes, the percentage of explants that started to grow four weeks after inoculation being 92%. The highest multiplication rate (7.12 shoots/explant) and the highest average shoot length (8.11 cm) were obtained on the MS medium supplemented with 1 mg/L benzylaminopurine, when nodal fragments were used as explants. The rooting phase was not necessary, the shoots developing roots on the multiplication medium. The acclimatization rate of in vitro regenerated plants to ex vitro conditions was 96%. Although biochemical investigations revealed some differences between in vitro regenerated plants and those obtained by conventional methods, the results obtained show that micropropagation can be used successfully to obtain high-quality peppermint biological material, a potential source of bioactive compounds with therapeutic effect.