Biotransformation of 5?H-pregnan-3?ol-20-one and cardenolides in cell suspension cultures of Nerium oleander L.

Paper, D.; Franz, Gerhard

doi:10.1007/bf00269985

Cited by 15 publications

(4 citation statements)

References 17 publications

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“…suspension cultures or root cultures of various plant species (see the reviews by Reinhard & Alfermann 1980, Suga& Hiram 1990. Suspension cultures of Nerium oleander were shown to form digitoxigenin fl-D-glucoside and 3-epidigitoxigenin H-Dglucoside (Paper & Franz 1990). Similar results have been obtained with cell suspension cultures of various Digitalis (see Reinhard & Alfermann 1980, for a review) and Strophanthus species (Kawaguchi et al 1988(Kawaguchi et al , 1989(Kawaguchi et al , 1991.…”

Section: Discussionsupporting

confidence: 69%

Glycosylation in cardenolide biosynthesis

Theurer

Treumann

Faust

et al. 1994

Plant Cell Tiss Organ Cult

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The glycosylation and deglycosylation of cardiac glycosides was investigated using cell suspension cultures and shoot cultures, both established from Digitalis lanata EHRH. plants, as well as isolated enzymes. Shoots were capable of glucosylating digitoxigenin, evatromonoside, digiproside, glucodigitoxigenin and digitoxin. Suspension cultured Digitalis cells glucosylated all the substrates mentioned but digiproside, whereas the UDP-glucosedependent cardenolide glucosyltransferase isolated from that source did not accept digitoxigenin and digiproside as substrates. It is concluded that at least three different glucosyltransferases are involved in cardiac glycoside formation in Digitalis. Similar experiments carried out with glucosylated cardenolides which were administered to cultured cells, shoots and a cardenolide/~-glucosidase isolated from young leaves revealed that at least two different glucosidases occur in Digitalis lanata, albeit in different tissues or during different phases of development. The biotransformation of glucoevatromonoside was investigated using unlabelled compound and [lac-glucose]glucoevatromonoside synthesized enzymatically. After 7 d of incubation almost no radioactivity could be recovered from the cardenolide fraction, indicating that the terminal glucose of glucoevatromonoside was now incorporated into volatile, hydrophilic and insoluble compounds. Since, on the other hand, large amounts of cardenolides were found in the experiments with unlabelled glucoevatromonoside it is assumed that steady state or pool size regulation is achieved by the coordinated action of a cardenolide glucosidase and a glucosyltransferase.Abbreviations: Acdox -D-acetyldigitoxose, dgen-digoxigenin, dox-D-digitoxose, dten -digitoxigenin, dtl -Ddigitalose, fuc-D-fucose, gten-gitoxigenin, qun-D-quinovose, CGH-cardenolide 16'-O-glucohydrolase, DFT -UDP-fucose:digitoxigenin 3-O-fucosyltransferase, DGT-UDP-glucose:Digitoxin 16'-O-glucosyltransferase, DQT -UDP-quinovose:digitoxigenin 3-O-quinovosyltransferase

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Section: Discussionsupporting

confidence: 69%

Glycosylation in cardenolide biosynthesis

Theurer

Treumann

Faust

et al. 1994

Plant Cell Tiss Organ Cult

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“…Digitoxigenin (1) has so far been fed to cell suspension cultures of several plant species [see (10) for a reviewl. In cell cultures initiated from Nerium oleander, I was either converted into 10 or epimerized via 3 into 2, which in turn was glucosylated to yield 3-epidigitoxigenin J3-u-glucoside (23).…”

Section: Discussionmentioning

confidence: 99%

Effects of Digitoxigenin, Digoxigenin, and Various Cardiac Glycosides on Cardenolide Accumulation in Shoot Cultures ofDigitalis lanata

Theurer

Kreis²,

Reinhard³

1998

Planta Med

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Various cardenolide genins and cardenolide glycosides were administered to light-grown and dark-grown Digitalis lanata shoot cultures to investigate conversion reactions related to the formation and rearrangement of the sugar side chain of Digitalis glycosides. Digitoxigenin was converted to digitoxigen-3-one, 3-epidigitoxigenin, and digoxigenin. In addition, various cardiac glycosides were formed, including mono-glycosides with glucose, glucomethylose, fucose, and digitalose, as well as the corresponding diglycosides, all containing a terminal glucose. Digitoxosylated cardenolides were not formed, although the light-grown shoot cultures were capable of producing these compounds. Exogenous cardenolide fucosides were not converted into cardenolide digitoxosides. Administration of evatromonoside (digitoxigenin monodigitoxoside) did not force the formation of cardenolide di- or tridigitoxosides. Our results support the hypothesis that cardenolide fucosides and digitoxosides are formed via different biosynthetic routes and that cardenolide genins can be fucosylated but not digitoxosylated, indicating that digitoxosylation may only occur at an earlier stage in the cardenolide pathway.

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“…Enzymes involved in the final glycosylation stage have been described from Digitalis species 1225,1226 and Nerium oleander. 1227 The biosynthesis of 5 -cardenolides in Asclepias curassavica has also been studied [1228][1229][1230] and the topic of cardenolide biosynthesis has been reviewed. 1231 Steroidal sapogenins such as diosgenin (106) 1232 and steroidal alkaloids such as solanidine (107), 1233 compounds probably involved in defence against fungal pathogens, are believed to be biosynthesised from cholesterol (Nohara has 672 Natural Product Reports, 1998 isolated a 26-aminocholestanol derivative which may be an intermediate in the formation of the steroidal alkaloids).…”

Section: Biosynthesis Of Plant Steroids and Triterpenes As Secondary ...mentioning

confidence: 99%

The biosynthesis of steroids and triterpenoids

Brown¹

1998

Nat. Prod. Rep.

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Biotransformation of 5?H-pregnan-3?ol-20-one and cardenolides in cell suspension cultures of Nerium oleander L.

Cited by 15 publications

References 17 publications

Glycosylation in cardenolide biosynthesis

Glycosylation in cardenolide biosynthesis

Effects of Digitoxigenin, Digoxigenin, and Various Cardiac Glycosides on Cardenolide Accumulation in Shoot Cultures ofDigitalis lanata

The biosynthesis of steroids and triterpenoids

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