Biotransformation of Cardiac Glycosides by Immobilized Cells of Digitalis lanata¹

Immobilised Plant Cell Culture Systems

“…Brodelius et al (1979) found that the 12,,8-hydroxylation of digitoxin to digoxin occurred in cells immobilised in a calcium alginate gel with the same efficiency of conversion as freely suspended cells, and activity was maintained for 33 days. Alfermann et al (1980) have reported how similarly immobilised D. lanata cells glycosylate digitoxin to purpure a glycoside A and hydroxylat~ ,8-methyldigitoxin to ,8-methyldigoxin in a way which is qualitatively identical to freely-suspended cells. The hydroxylation activity was only 50% that of suspended cells, but was maintained for at least 61 days.…”

“…The first is one-or twostep biotransformations such as hydroxylations, glycosylations, acetylations, and demethylations. The greatest volume of published data so far has been on the hydroxylation or glycosylation of cardiac glycosides in either Digitalis lanata (Brodelius et al 1979;Alfermann et al 1980) or in Daucus carota (Jones and Veliky 1981). Brodelius et al (1979) found that the 12,,8-hydroxylation of digitoxin to digoxin occurred in cells immobilised in a calcium alginate gel with the same efficiency of conversion as freely suspended cells, and activity was maintained for 33 days.…”

Glucosylation of cyclodextrin-complexed podophyllotoxin by cell cultures of Linum flavum L.

“…Therefore, studies on glycosylation of natural or synthetic compounds by plant cell enzymes can contribute to the production of glycosides of pharmaceutical interest. Several plant cell cultures have been shown to be capable to glucosylate exogenously supplied compounds including cardenolides (Alfermann et al 1980;D6Uer et al 1977), flavonoids (Lewinson et al 1989), phenolics (Mizukami et al 1983(Mizukami et al , 1986Scholten et al 1991;Tabata et al 1976Tabata et al , 1984Tabata et al , 1988, steroids (Furuya 1978) and terpenoids (Furuya 1978).…”

Vegetables as Chemical Reagents

“…81 Similar results were subsequently observed by Reinhard and coworkers using immobilized cells of Digitalis lanata Ehrhart to transform cardiac glycosides. 82 In this instance, digitoxin (45) was transformed to purpurea glycoside A (47), and 16-hydroxylation to digoxin (49) also occurred. The metabolic activity remained constant for at least 61 days.…”

“…The metabolic activity remained constant for at least 61 days. 82 Suga and co-workers were the first to examine the biotransformation of simple monoterpenes by plant tissue cultures when they cultured Nicotiana tabacum "Bright Yellow" with a series of monoterpenes for 7 days. The dominant reaction was regioselective oxidation of the E-methyl group to a hydroxymethyl group.…”