Scopolamine Production in Suspension Cultures and Redifferentiated Roots of<i>Hyoscyamus niger</i>

Hashimoto, Takashi; Yamada, Yasuyuki

doi:10.1055/s-2007-969984

Cited by 85 publications

(24 citation statements)

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“…Part of these data has been reported (11). Duboisia shoot cultures and Hyoscyamus callus cultures were established as described previously (24,25), and cultured on LS agar medium, respectively, with 10 This finding argues against the proposed biosynthetic pathway for scopolamine (22) in which hyoscyamine is first dehydrogenated to 6,7-dehydrohyoscyamine. If 6,7-dehydrohyoscyamine is a precursor of scopolamine, it shoud be located between 6fl-hydroxyhyoscyamine and scopolamine (14,19).…”

Section: Discussionmentioning

confidence: 99%

“…Root cultures of Hyoscyamus niger L. have notably high ratios of scopolamine to hyoscyamine. The remarkable ability of the root cultures of this species to synthesize scopolamine was demonstrated in an experiment in which a large proportion of an exogeneous supply of hyoscyamine was converted to scopolamine (10). Thus, root cultures of H. niger appear to be of use for studies of the biosynthetic pathway from hyoscyamine to scopolamine.…”

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confidence: 99%

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Hyoscyamine 6β-Hydroxylase, a 2-Oxoglutarate-Dependent Dioxygenase, in Alkaloid-Producing Root Cultures

Hashimoto

Yamada²

1986

Plant Physiol.

173

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Root cultures of various solanaceous plants grow well in vitro and produce large amounts of tropane alkaloids. Enzyme activity that converts hyoscyamine to 6,6-hydroxyhyoscyamine is present in cell-free extracts from cultured roots of Hyoscyamus niger L. The enzyme hyoscyamine 6,6-hydroxylase was purified 3.3-fold and characterized. The hydroxylation reaction has absolute requirements for hyoscyamine, 2-oxoglutarate, Fe2" ions and molecular oxygen, and ascorbate stimulates this reaction. Only the L-isomer of hyoscyamine serves as a substrate; Dhyoscyamine is nearly inactive. Comparisons were made with a number of root, shoot, and callus cultures of the Atropa, Datura, Duboisia, Hyoseyamus, and Nicotiana species for the presence of the hydroxylase activity. Decarboxylation of 2-oxoglutarate during the conversion reaction was studied using [1-'4Cj-2-oxoglutarate. A 1:1 stoichiometry was shown between the hyoscyamine-dependent formation of CO2 from 2-oxoglutarate and the hydroxylation of hyoscyamine. Therefore, the enzyme can be classified as a 2-oxoglutarate-dependent dioxygenase (EC 1.14.11.-). Both the supply of hyoscyamine and the hydroxylase activity determine the amounts of 6,B-hydroxyhyoscyamine and scopolamine produced in alkaloid-producing cultures.Tropane alkaloid molecules are characterized by the presence ofa bicyclic amine tropane ring system. Although these alkaloids are distributed in several families that are not related taxonomically, tropic acid esters of hydroxytropane derivatives (e.g. hyoscyamine and scopolamine) are restricted to Solanaceae species Atropa, Datura, Duboisia, Hyoscyamus, and Scopolia (3, 18). The biosynthesis of tropane alkaloids in plants has been investigated extensively with labeled precursors (for a recent review, see Leete [14]). Ornithine is incorporated into the pyrrolidine ring of tropine, whereas tropic acid is formed by the intramolecular rearrangement of thQ side chain of phenylalanine. Tropine and tropic acid then condense to give hyoscyamine. Scopolamine is formed from hyoscyamine via 6(-hydroxyhyoscyamine (19) (Fig. 1). 63-Hydroxyhyoscyamine has been isolated from several solanaceous plants (4,11,18).None of the exact biosynthetic reactions or enzymes that function in the oxidative conversion of hyoscyamine to scopolamine are known. Fodor et al. (5) reported that when a solution of 6,7-dehydrohyoscyamine was fed to almost alkaloid-free scions of Datura ferox L. grafted on Cyphomandra betacea cv Sendtn., scopolamine could be isolated from the Datura scions after a week (Fig. 1). On the basis of that report, Waller and Nowacki (22) speculated that hyoscyamine is first dehydrogenated to 6,7-dehydrohyoscyamine which then is converted via 6j3-hydroxyhyoscyamine to scopolamine. By contrast, Fodor et al. (5) Previously (1 1), we reported the successful establishment of root cultures of several alkaloid-containing solanaceous plants. These cultured roots grow vigorously when the culture medium is supplemented with IBA,' and alkaloid biosynthesis is stimulated aft...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Hyoscyamine 6β-Hydroxylase, a 2-Oxoglutarate-Dependent Dioxygenase, in Alkaloid-Producing Root Cultures

Hashimoto

Yamada²

1986

Plant Physiol.

173

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“…Furthermore a potentiometric determination, a radioimmune assay and even N M R spectroscopy have been reported [3 -11]; these procedures have mostly used dried plant material. Our procedure is a modification of an extraction protocol for Datura cell suspension cul tures [12] in combination with a HPLC protocol ap plied for the determination of nicotine from tobacco [13]. After completion of this work, an HPLC assay was described [14] based on a reversed phase matrix.…”

Section: Introductionmentioning

confidence: 99%

Determination of Hyoscyamine and Scopolamine in Datura innoxia Plants by High Performance Liquid Chromatography

Plank¹,

Wagner²

1986

Zeitschrift Für Naturforschung C

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Datura innoxia, Tropane Alkaloids, High Performance Liquid ChromatographyFor the determination of the hyoscyamine-scopolamine content in small quantities of fresh plant tissue an HPLC assay was developed; with a sensitivity of about 20 ng alkaloid per run. Analysis of the different organs of Datura innoxia plants are in accord with the concept that hyoscyamine is synthesized in the roots, whereas transformation to scopolamine starts in these organs and proceeds in the aerial parts of the plant.

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“…It seems that the epoxidation reaction occurs much more slowly than the hydroxylation reaction. The tropane alkaloids seem to be formed in the roots and then transported to the aerial parts of the plant (163).…”

Section: Tropane Alkaloidsmentioning

confidence: 99%

Alkaloid Biosynthesis

O’Connor

2008

Wiley Encyclopedia of Chemical Biology

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How nature synthesizes complex secondary metabolites, or natural products, can be studied only by working within the disciplines of both chemistry and biology. Alkaloids are a complex group of natural products with diverse mechanisms of biosynthesis. This article highlights the biosynthesis of four major classes of plant‐derived alkaloids. Only plant alkaloids for which significant genetic information has been obtained were chosen for review. Isoquinoline alkaloid, terpenoid indole alkaloid, tropane alkaloid, and purine alkaloid biosynthesis are described here. The article is intended to provide an overview of the basic mechanism of biosynthesis for selected members of each pathway. Manipulation of these pathways by metabolic engineering is highlighted also.

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Scopolamine Production in Suspension Cultures and Redifferentiated Roots ofHyoscyamus niger

Cited by 85 publications

References 11 publications

Hyoscyamine 6β-Hydroxylase, a 2-Oxoglutarate-Dependent Dioxygenase, in Alkaloid-Producing Root Cultures

Hyoscyamine 6β-Hydroxylase, a 2-Oxoglutarate-Dependent Dioxygenase, in Alkaloid-Producing Root Cultures

Determination of Hyoscyamine and Scopolamine in Datura innoxia Plants by High Performance Liquid Chromatography

Alkaloid Biosynthesis

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