Hyoscyamine-6beta-hydroxylase (H6H; EC 1.14.11.11) catalyses oxidative reactions in the biosynthetic pathway leading from hyoscyamine to the more pharmaceutically valuable tropane alkaloid scopolamine. The h6h gene encoding H6H from Hyoscyamus niger was introduced, under the control of the CaMV 35S promoter, into non-hyoscyamine-producing Nicotiana tabacum and hyoscyamine-producing Hyoscyamus m...

Hyoscyamine, anisodamine and scopolamine are tropane alkaloids present in some Solanaceae species used modern medicine. L-Hyoscyamine is hydroxylated to 6β-hydroxyhyoscyamine (anisodamine) then epoxidated by the dual action of hyoscyamine 6β-hydroxylase (H6H), a 2-oxoglutarate dependent dioxygenase. A natural mutation Gly-220 residue Cys was previously shown be associated with loss function H6H...

BACKGROUND Tropane alkaloids, mainly hyoscyamine and scopolamine, are widely used in medicine due to their anticholinergic activity. Scopolamine has a higher demand being the more valuable alkaloid due to its fewer side effects and higher physiological activity. Anisodamine (6beta-hydroxyhyoscyamine) is the intermediate in the conversion of hyoscyamine into scopolamine. Current studies report t...

Reversible acetylcholinesterase inhibitors are used as first-line treatment for myasthenia gravis. They improve symptoms by increasing concentration of acetylcholine at the neuromuscular junction and stimulating nicotinic receptors. Serious bradyarrhythmias can occur from muscarinic stimulation in heart, which in rare cases may progress to asystole. These patients can initially be managed with ...

Hyoscyamine is epoxidized to scopolamine via 6beta-hydroxyhyoscyamine in several solanaceous plants. 6,7-Dehydrohyoscyamine has been proposed to be an intermediate in the conversion of 6beta-hydroxyhyoscyamine to scopolamine on the basis of the observation that this unsaturated alkaloid is converted to scopolamine when fed to a Datura scion. To determine whether a dehydration step is involved i...

For 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 t...

Hyoscyamus albus is a well-known source of the tropane alkaloids, hyoscyamine and scopolamine, which are biosynthesized in the roots. To assess the major biochemical adaptations that occur in the roots of this plant in response to iron deficiency, we used a small-scale proteomic approach in which 100 mg of root tips were treated with and without Fe, respectively, for 5 days. Two-dimensional min...

The tropane alkaloids, hyoscyamine and scopolamine, are medicinal compounds that are the active components of several therapeutics. Hyoscyamine and scopolamine are synthesized in the roots of specific genera of the Solanaceae in a multistep pathway that is only partially elucidated. To facilitate greater understanding of tropane alkaloid biosynthesis, a de novo transcriptome assembly was develo...