Chemical potential of Aphelandra sp. cell cultures

Abstract

Six different callus lines and three different suspension culture lines were established from plants of two Aphelandra species (Acanthaceae). All established lines were analyzed for secondary metabolite accumulation. A discrepancy between secondary metabolites accumulated in the plants and in the cell cultures could be observed. All established Aphelandrasp. cell cultures produced verbascoside (acteoside) as the major extractable metabolite. Time course experiments were carried out to investigate the relationship between cell growth and verbascoside production. In the present study it was shown that verbascoside accumulation was growth dependent and positively related to the presence of 2,4-D in the medium. The conditions in which verbascoside represents ca. 18% of cell culture weight have been defined. Free polyamines were detected in the cell culture lines cultivated in MS liquid medium (cysteine 10 mg l^-1, thiamine 1 mg l^-1, 2,4-D 1 mg l^-1, kinetin 0.2 mg l^-1 and sucrose 30 g l^-1). Putrescine and spermidine accumulated within 8 days to a maximum of 8.4 μmol g^-1 of dry wt and 2.6 μmol g^-1 of dry wt respectively and thereafter their concentration decreased rapidly. There was no evidence for the presence of spermine or any other type of free or conjugated polyamines in the tested cell culture lines.