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Time-Course Studies on The Use of Secologanin by Catharanthus roseus Cells Cultured in vitro

1989; Elsevier BV; Volume: 134; Issue: 5 Linguagem: Inglês

10.1016/s0176-1617(89)80156-7

1618-1328

F. Naudascher, Pierre Doireau, A. Guillot, C. Viel, Martine Thiersault,

Plant tissue culture and regeneration

Secologanin was not detected in Catharanthus roseus cell suspensions which had not been supplied with this compound. Secologanin introduced into a suspension 10 days after the start of subculture rapidly disappeared from the medium. The intracellular content of secologanin peaked at 75 %, then decreased to 20 % of the amount provided and remained at this level. This observation might be explained by the existence of an inactive pool which would not have been fed in the control cells. During the first hours after secologanin had been added, about 40 % of the total quantity (in both cells and medium) seemed to temporarily disappear. Such a disappearance is governed by the presence of cells, for it does not occur in a culture medium deprived of cells. Re-conversion of secologanin into loganin, demethylation of secologanin or loganin, conjugation of loganin or loganic acid with p-coumaric acid do not account for this disappearance. No clear explanation of this disappearance phenomenon can be given at present. Similar results were obtained when secologanin was added 4 days after initiation of subculture. However, in this case, intracellular content peaked at 96 %; the final constant level was about 50 %. The results are discussed in light of previous reports describing alkaloid accumulation and time-courses of related enzyme activities in the same material.