Hyoscyamine

Hyoscyamine is an AChR inhibitor with IC50 of 7.5 nM.

Use of atropine-diphenoxylate compared with hyoscyamine to decrease rates of irinotecan-related cholinergic syndrome.[Pubmed:25839059]

J Community Support Oncol. 2015 Jan;13(1):3-7.

BACKGROUND: Cholinergic syndrome is a well established acute adverse reaction associated with irinotecan. Cholinergic side effects can be ameliorated or prevented with anticholinergic agents. To date, no formal studies have compared atropine-diphenoxylate and Hyoscyamine as premedications for prophylaxis of the cholinergic syndrome with irinotecan infusion. OBJECTIVES: To compare the incidence of cholinergic syndrome with irinotecan using atropine-diphenoxylate or Hyoscyamine as premedication. METHODS: We conducted a retrospective, single-center, nonrandomized, cohort study of adult patients treated with atropine-diphenoxylate or Hyoscyamine as premedication before receiving irinotecan. For all irinotecan infusions, intravenous atropine was administered for patients experiencing any cholinergic reaction. RESULTS: A total of 532 irinotecan cycles (354 cycles for atropine-diphenoxylate group; 178 cycles for Hyoscyamine group) were analyzed in 80 patients. Overall incidence of cholinergic syndrome did not differ between atropine-diphenoxylate (8.2%) and Hyoscyamine (9.0%) groups (P = .76). The incidence of cholinergic syndrome after the poundrst cycle of irinotecan was similar between the 2 arms, atropine-diphenoxylate (14.6%) and Hyoscyamine (10.7%), with P = .74. The most common cholinergic symptoms documented were abdominal pain or cramping, and diarrhea. LIMITATIONS: This study was subjected to vulnerabilities to bias and random error because of its observational retrospective design and small number of participants. CONCLUSIONS: Lack of difference in the incidence of cholinergic syndrome observed in irinotecan-treated patients suggests atropinediphenoxylate and Hyoscyamine may both be effective prophylactic options. The findings support the need for a larger, randomized study to assess and compare these agents with other potential premedications such as scopolamine and atropine in prevention of irinotecan-related cholinergic syndrome.

Antispasmodic drugs to reduce discomfort and colonic spasm during barium enemas: comparison of oral hyoscyamine, i.v. glucagon, and no drug.[Pubmed:8273637]

AJR Am J Roentgenol. 1993 Nov;161(5):965-8.

OBJECTIVE: Parenterally administered glucagon is currently the agent of choice for reducing abdominal discomfort and colonic spasm during a barium enema. Because glucagon is expensive and frequently causes nausea, we evaluated the use of oral Hyoscyamine sulfate as an alternate agent and compared it with IV glucagon and no medication. SUBJECTS AND METHODS: A total of 349 adult patients undergoing barium enema examinations were randomly assigned in a prospective fashion to one of four groups: (1) no medication (87 patients); (2) 1 mg of IV glucagon (88 patients); (3) 0.125 mg of oral Hyoscyamine sulfate (87 patients); and (4) 0.25 mg of oral Hyoscyamine sulfate (87 patients). The degree of distension of the colon on radiographs obtained after fluoroscopy, the amount of abdominal distress after the procedure, and the number of side effects (nausea, palpitations, blurred vision, dry mouth) were analyzed. To evaluate the amount of abdominal discomfort more completely, we asked the last 248 patients to estimate the level of severity of the discomfort (none, mild, moderate, or severe). RESULTS: We found no difference in the degree of distension of the colon in the four groups (p = .63). Most patients (79%) had some degree of abdominal discomfort. Fewer patients in the group who received no medication (10%) had no or mild pain compared with those given glucagon (15%, p < .05), 0.125 mg of Hyoscyamine (14%, p < .05), or 0.25 mg of Hyoscyamine (12%, p = .15). Less nausea occurred in the group that received 0.125 mg of Hyoscyamine than in the other groups (p < .03). No patients in any of the groups had allergic or severe side effects. CONCLUSION: When compared with IV glucagon, oral Hyoscyamine had fewer side effects, but the degree of colonic distension or abdominal distress was not significantly different. In addition, Hyoscyamine is considerably less expensive than glucagon and can be given orally. Patients who received medications had less discomfort than those who did not. However, the degree of distension was not different.

Multi-development-HPTLC method for quantitation of hyoscyamine, scopolamine and their biosynthetic precursors in selected solanaceae plants grown in natural conditions and as in vitro cultures.[Pubmed:23839972]

Phytochem Anal. 2014 Jan-Feb;25(1):29-35.

INTRODUCTION: Hyoscyamine and scopolamine, anti-cholinergic agents widely used in medicine, are typically obtained from plants grown under natural conditions. Since field cultivation entails certain difficulties (changeable weather, pests, etc.), attempts have been made to develop a plant in vitro culture system as an alternative source for the production of these compounds. During experiments to locate the limiting steps in the biotechnological procedure, it is important to monitor not only the levels of the final products but also the changes in the concentration of their precursors. OBJECTIVE: To develop a HPTLC method for the separation and quantitation of the main tropane alkaloids Hyoscyamine and scopolamine, their respective direct precursors littorine and anisodamine, and cuscohygrine, a product of a parallel biosynthetic pathway that shares a common precursor (N-methyl-(1) -pyrrolium cation) with tropane alkaloids. METHODS: Using alkaloid extracts from Atropa baetica hairy roots, different TLC chromatographic systems and developing procedures were investigated. RESULTS: Full separation of all compounds was obtained on HPTLC Si60 F254 plates preconditioned with mobile phase vapours (chloroform:methanol:acetone:25% ammonia ratios of 75:15:10:1.8, v/v/v/v). The chromatograms were developed twice (at distances of 4.0 and 3.0 cm) in a Camag twin trough chamber and visualised with Dragendorff's reagent. Densitometric detection (lambda = 190 and 520 nm) was used for quantitative analyses of the different plant samples. CONCLUSION: This method can be recommended for quantitation of Hyoscyamine, scopolamine, anisodamine, littorine and cuscohygrine in different plant material (field grown vs. in vitro cultures).

Expression of Brugmansia candida Hyoscyamine 6beta-Hydroxylase gene in Saccharomyces cerevisiae and its potential use as biocatalyst.[Pubmed:18505565]

Microb Cell Fact. 2008 May 27;7:17.

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 that this alkaloid is potentially applicable in medicine. The gene that codifies for Hyoscyamine 6-beta hydroxylase, the enzyme responsible for Hyoscyamine hydroxylation and epoxidation, leading to scopolamine was isolated from Brugmansia candida. RESULTS: The h6hcDNA was cloned into pYES2.1 and pYES2.1/V5-His-TOPO vectors to produce an untagged and a tagged protein, respectively. The H6H enzyme was produced in Saccharomyces cerevisiae in order to obtain a biological catalyst for potential industrial applications. Protein extracts of the induced yeast were analyzed by Western blot. The expression was detected 4 h after induction and no degradation was observed during the period assayed. The tagged and the untagged proteins were able to transform Hyoscyamine, showing a functional expression of the h6hcDNA. CONCLUSION: The strains obtained in this work are promising and potentially applicable in biocatalytic processes.