Stimulation of menthol production in Mentha piperita cell culture

Plant cell culture provides an alternative means for producing secondary metabolites. In this study, experiments were carried out to study the impact of several parameters, independently and in combination, on the stimulation of menthol production in the cell suspension culture of Mentha piperita. Callus was obtained from leaf segments of in vitro grown plantlets on Murashige and Skoog (MS) medium supplemented with 0.2 mg l(-1)of 2,4-dichlorophenoxy acetic acid to initiate cell suspension culture. This culture was maintained in half-strength MS medium supplemented with 0.2 mg l(-1)of 2,4-dichlorophenoxy acetic acid at 15 d interval and used for further studies. Precursor feeding alone, i.e., menthone, at 35 mu M concentration showed slightly improved productivity. gamma-Cyclodextrin alone at 60 mu M concentration and in combination with menthone feeding at 35 mu M increased menthol yield up to 92 and 110 mg l(-1) in comparison to 77 mg l(-1) of control culture. Synergistic potentiation effect of menthone feeding at 35 mu M and gamma-cyclodextrin at 60 mu M treatment followed by in situ adsorption with RP-8 also showed potential stimulation of menthol production in M. piperita cell culture. Fungal elicitor treatment showed enhanced production level up to 140.8 mg l(-1) in comparison to that of control. Further studies were carried out with the establishment of Agrobacterium tumefaciens (Ach5) gall-mediated calli, and consequently, cell suspension culture and results showed the significant enhancement of menthol yield up to 278 mg l(-1).