Enhanced silymarin accumulation is related to calcium deprivation in cell suspension cultures of Silybum marianum (L.) Gaertn.

Elimination of calcium ions from the medium of cell cultures of Silybum marianum (L.) Gaertn increased flavonolignan production. Silymarin accumulation was not altered by treatment of cultures with the calcium ionophore A23187. The specific Ca2+ chelator, EGTA, enhanced the silymarin content in cells by 200%, and its secretion by 3-4 times. The inorganic ion La3+, as well as the calcium channel inhibitor verapamil, also stimulated production. Several reagents known to block intracellular calcium movement, such as ruthenium red, thapsigargin and TMB-8 appreciably increased silymarin accumulation. These results suggest that inhibition of external and internal calcium fluxes plays a significant role in flavonolignan metabolism of S. marianum cell cultures.