Laudanosine

Death from Poppy Tea Consumption.[Pubmed:33043985]

J Anal Toxicol. 2020 Oct 12;44(7):734-740.

The historical practice of brewing poppy tea for its opioid-like effects is reoccurring with modern-day substance users. We present four postmortem cases with toxicology results that serve as case studies for the potential hazards of poppy tea ingestion. There is limited information regarding the risks of this practice due to the variability of the morphine content of the opium exuded from the plant. While internet tea recipes offer guidance, differences in poppy cultivation, washing, and infusing time are some of the reasons why the beverage may contain inconsistent and clinically significant alkaloid concentrations for each preparation. Variability in opioid tolerance along with additional drugs taken will impact the overall degree of toxicity experienced from the opiates in the tea. Advancements in the genetic modification of the poppy plant could greatly alter the ratio of alkaloids seen in biological fluids and will be highly dependent on the source of the poppy product. The blood concentrations of free morphine and free codeine in cases 1-3 where the toxicity from the tea was considered the primary cause of death were 0.94 and 0.11 mg/L, 0.62 and 0.034 mg/L, and 0.16 and 0.010 mg/L, respectively. The urine concentrations of morphine and codeine were 13 and 0.94 mg/L in case 1 and 16 and 1.6 mg/L in case 2, respectively. The opium alkaloids thebaine and Laudanosine were identified qualitatively by our routine organic base/neutral drug detection procedure.

HPLC-Based Activity Profiling for Antiprotozoal Compounds in Croton gratissimus and Cuscuta hyalina.[Pubmed:32922290]

Front Pharmacol. 2020 Aug 14;11:1246.

In a screening of Sudanese medicinal plants for antiprotozoal activity, the chloroform fractions obtained by liquid-liquid partitioning from ethanolic extracts of fruits of Croton gratissimus var. gratissimus and stems of Cuscuta hyalina Roth ex Schult. exhibited in vitro activity against axenically grown Leishmania donovani amastigotes. This antileishmanial activity was localized by HPLC-based activity profiling. Targeted preparative isolation afforded flavonoids 1-6, 3-methoxy-4-hydroxybenzoic acid (7), and benzyltetrahydroisoquinoline alkaloids laudanine (8) and Laudanosine (9) from C. gratissimus, and pinoresinol (10), isorhamnetin (11), (-)-pseudosemiglabrin (12), and kaempferol (13) from C. hyalina. The antiprotozoal activity of 1-13 against L. donovani (axenic and intracellular amastigotes), Trypanosoma brucei rhodesiense (bloodstream forms), and Plasmodium falciparum (erythrocytic stages), and the cytotoxicity in L6 murine myoblast cells were determined in vitro. Quercetin-3,7-dimethylether (6) showed the highest activity against axenic L. donovani (IC50, 4.5 microM; selectivity index [SI], 12.3), P. falciparum (IC50, 7.3 microM; SI, 7.6), and T. b. rhodesiense (IC50, 2.4 microM; SI, 23.2). The congener ayanin (2) exhibited moderate antileishmanial (IC50, 8.2 microM; SI, 12.2), antiplasmodial (IC50, 7.8 microM; SI, 12.9), and antitrypanosomal activity (IC50, 11.2 microM; SI, 8.9). None of the compounds showed notable activity against the intramacrophage form of L. donovani.

General and Efficient Copper-Catalyzed Oxazaborolidine Complex in Transfer Hydrogenation of Isoquinolines under Mild Conditions.[Pubmed:32875258]

ACS Omega. 2020 Aug 13;5(33):21219-21225.

A general and efficient method for copper-catalyzed transfer hydrogenation of isoquinolines with an oxazaborolidine-BH3 complex, under mild reaction conditions, is successfully developed. A broad range of isoquinolines has been reduced to the corresponding products with 61-85% yields. The method is applied to the synthesis of biologically active tetrahydrosioquinoline alkaloid (+/-)-norLaudanosine in 62% yield, which is the key precursor for the preparation of (+/-)-Laudanosine, (+/-)-N-methyl-Laudanosine, and (+/-)-xylopinine in one or two steps.

Effect of age on cis-atracurium besylate pharmacokinetics following a single 1 mg kg(-1) intravenous bolus in young pigs.[Pubmed:31155378]

Vet Anaesth Analg. 2019 Sep;46(5):643-651.

OBJECTIVE: To determine the cis-atracurium pharmacokinetic data and Laudanosine production of a single 1 mg kg(-1) cis-atracurium dose in the pig and to compare the pharmacokinetics between two groups of different ages. STUDY DESIGN: Prospective experimental study. ANIMALS: Sixteen female pigs in two groups. Group A included eight animals aged 2.0-2.5 months and weighed 26.6 +/- 3.6 kg. Group B included eight animals aged 4.0-5.0 months and weighed 57.4 +/- 8.3 kg. METHODS: The pigs were anaesthetized and monitored throughout the procedure. Arterial blood samples collected at 0, 0.5, 1, 2, 5, 10, 20, 30, 45, 60, 90, 120 and 180 minutes after cis-atracurium injection were cooled and centrifuged. Plasma was acidified and stored at -20 degrees C for subsequent cis-atracurium and Laudanosine analyses. RESULTS: Anaesthetic parameters were within normal ranges throughout the procedure. Plasma cis-atracurium and Laudanosine concentrations were measured for the 16 pigs. Elimination rate constant, elimination half-life, area under the curve, mean residence time, distribution volume and total clearance were calculated for each pig. Statistical differences (p < 0.05) in the elimination rate constant, elimination half-life, mean residence time and distribution volume values were observed between the two groups. Elimination half-life, mean residence time and distribution volume values were higher and elimination rate constant lower in younger pigs than in older pigs. No plasma Laudanosine concentrations were detected in any pig. CONCLUSION AND CLINICAL RELEVANCE: Longer duration of plasma cis-atracurium concentrations were observed in younger pigs. Distribution volume was also higher in younger pigs. Conversely, total clearance and area under the curve were similar between the two age groups. No Laudanosine production was detected, suggesting a different cis-atracurium metabolism in the pig compared with other species.

Antimicrobial activity of leaf extracts and isolated constituents of Croton linearis.[Pubmed:30849504]

J Ethnopharmacol. 2019 May 23;236:250-257.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaves of Croton linearis, known as "rosemary", are widely used in folk medicine in Caribbean countries to treat fever and colds (associated to infections). AIM OF THE STUDY: To evaluate the in vitro antimicrobial activity of extracts and fractions derived from C. linearis leaves. MATERIALS AND METHODS: Bioassay-guided fractionation and isolation of compounds from an ethanolic extract of C. linearis, using flash chromatography and semi-preparative HPLC-DAD-MS (High Performance Liquid Chromatography - Diode Array Detection - Mass Spectrometry). Isolated compounds were characterized by MS, 1D- and 2D-NMR (Nuclear Magnetic Resonance) spectroscopy. The microdilution method with resazurin, as well as direct counting with an optical microscope, were used to determine the in vitro antimicrobial activity against bacteria, fungi and parasites. Moreover, the cytotoxicity on human fetal lung fibroblasts (MRC-5) was evaluated. RESULTS: The total extract and chloroform fraction (ClF) showed high activity against protozoa with IC50 values ranging from 1 to 26mug/mL, but also cytotoxicity on MRC-5 and PMM (Peritoneal Murine Macrophages). Seven compounds were isolated and characterized for first time in this species: the alkaloids laudanidine, Laudanosine, reticuline, corydine, glaucine and cularine and the flavonoid glycoside isorhamnetin-3-O-(6''O-p-trans-coumaroyl)-beta-glucopyranoside. Reticuline showed a weak activity against L. infantum (IC50 148.0+/-1.2muM), while the flavonoid was active against T. cruzi (IC50 35.6+/-2.3muM). CONCLUSIONS: The results show the antiprotozoal potential of the extract and some isolated constituents, which supports the use of this species in Caribbean folk medicine.

Total Synthesis of (-)-Oxycodone via Anodic Aryl-Aryl Coupling.[Pubmed:30775928]

Org Lett. 2019 Mar 15;21(6):1828-1831.

A fully regio- and diastereoselective electrochemical 4a-2'-coupling of a 3',4',5'-trioxygenated Laudanosine derivative enables the synthesis of the corresponding morphinandienone. This key intermediate is further transformed into (-)-oxycodone through conjugate nucleophilic substitution for E-ring closure and [4 + 2] cycloaddition with photogenerated singlet oxygen to accomplish diastereoselective hydroxylation at C-14. The anodic transformation provides high yields and can be performed under constant current conditions both in a simple undivided cell or in continuous flow.

Evaluation of the enantioselectivity of capillary electrokinetic chromatography using ethanediamine-bonded poly (glycidyl methacrylate) microspheres as the pseudostationary phases.[Pubmed:30609130]

Chirality. 2019 Feb;31(2):118-126.

In this work, a new capillary electrokinetic chromatography (EKC) approach using ethanediamine-bonded poly (glycidyl methacrylate) (Ami-PGMA) microspheres as pseudostationary phases (PSPs) for enantioseparation with a polysaccharide, chondroitin sulfate E (CSE), as the chiral selector. The CSE@Ami-PGMA EKC system was applied to enantioseparate basic drugs, and distinct improved separations of tested enantiomers were obtained while comparing with the single CSE system (the resolution increased from 0.41 to 1.26 for nefopam, from 1.24 to 2.15 for Laudanosine, and from 0.92 to 2.36 for amlodipine). The Ami-PGMA microspheres were fully characterized by scanning electron microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy, and the results showed Ami-PGMA microspheres were uniform and spherical in size (1 mum). Several principal parameters were systematically investigated, and the optimal chiral separations were obtained with Tris/H3 PO4 (20 mM, pH 2.4, and 3.4 for NEF) containing 2.5% (w/v) CSE and 20-mug Ami-PGMA microspheres in 20 degrees C. Subsequently, the concentrations of Ami-PGMA microspheres and CSE were proved to be the dominant factors for the separation in the CSE@Ami-PGMA EKC system by Statistical Product and Service Solutions (SPSS).

A Regio- and Diastereoselective Anodic Aryl-Aryl Coupling in the Biomimetic Total Synthesis of (-)-Thebaine.[Pubmed:29786941]

Angew Chem Int Ed Engl. 2018 Aug 20;57(34):11055-11059.

The biosynthesis of thebaine is based on the regioselective, intramolecular, oxidative coupling of (R)-reticuline. For decades, chemists have sought to mimic this coupling by using stoichiometric oxidants. However, all approaches to date have suffered from low yields or the formation of undesired regioisomers. Electrochemistry would represent a sustainable alternative in this respect but all attempts to accomplish an electrochemical synthesis of thebaine have failed so far. Herein, a regio- and diastereoselective anodic coupling of 3',4',5'-trioxygenated Laudanosine derivatives is presented, which finally enables electrochemical access to (-)-thebaine.

Real-time potentiometric sensor; an innovative tool for monitoring hydrolysis of chemo/bio-degradable drugs in pharmaceutical sciences.[Pubmed:29549855]

J Pharm Biomed Anal. 2018 May 30;154:166-173.

In recent years, the whole field of ion-selective electrodes(ISEs) in pharmaceutical sciences has expanded far beyond its original roots. The diverse range of opportunities offered by ISEs was broadly used in a number of pharmaceutical applications, with topics presented ranging from bioanalysis of drugs and metabolites, to protein binding studies, green analytical chemistry, impurity profiling, and drug dissolution in biorelevant media. Inspired from these advances and with the aim of extending the functional capabilities of ISEs, the primary focus of the present paper is the utilization of ISE as a tool in personalized medicine. Given the opportunity to explore biological events in real-time (such as drug metabolism) could be central to personalized medicine. (ATR) is a chemo-degradable and bio-degradable pharmaceutically active drug. Laudanosine (LDS) is the major degradation product and metabolite of ATR and is potentially toxic and reported to possess epileptogenic activity which increases the risk of convulsive effects. In this work, ATR have been subjected to both chemical and biological hydrolysis, and the course of the reactions is monitored by means of a ISE. In this study, we have designed an efficient real-time tracking strategy which substantially resolve the challenges of the ATR chemical and biological degradation kinetics. By utilizing a potentiometric sensor, tracking of ATR chemical and biological degradation kinetics can be performed in a very short time with excellent accuracy. The LOD was calculated to be 0.23mumolL(-1), the potential drift was investigated over a period of 60min and the value was 0.25mVh(-1). Real serum samples for measurement the rate of in vitro metabolism of ATR was performed. Furthermore, a full description of the fabricated screen-printed sensor was presented.

Cholinesterase and Prolyl Oligopeptidase Inhibitory Activities of Alkaloids from Argemone platyceras (Papaveraceae).[Pubmed:28708094]

Molecules. 2017 Jul 14;22(7). pii: molecules22071181.

Alzheimer's disease is an age-related, neurodegenerative disorder, characterized by cognitive impairment and restrictions in activities of daily living. This disease is the most common form of dementia with complex multifactorial pathological mechanisms. Many therapeutic approaches have been proposed. Among them, inhibition of acetylcholinesterase, butyrylcholinesterase, and prolyl oligopeptidase can be beneficial targets in the treatment of Alzheimer's disease. Roots, along with aerial parts of Argemone platyceras, were extracted with ethanol and fractionated on an alumina column using light petrol, chloroform and ethanol. Subsequently, repeated preparative thin-layer chromatography led to the isolation of (+)-Laudanosine, protopine, (-)-argemonine, allocryptopine, (-)-platycerine, (-)-munitagine, and (-)-norargemonine belonging to pavine, protopine and benzyltetrahydroisoquinoline structural types. Chemical structures of the isolated alkaloids were elucidated by optical rotation, spectroscopic and spectrometric analysis (NMR, MS), and comparison with literature data. (+)-Laudanosine was isolated from A. platyceras for the first time. Isolated compounds were tested for human blood acetylcholinesterase, human plasma butyrylcholinesterase and recombinant prolyl oligopeptidase inhibitory activity. The alkaloids inhibited the enzymes in a dose-dependent manner. The most active compound (-)-munitagine, a pavine alkaloid, inhibited both acetylcholinesterase and prolyl oligopeptidase with IC50 values of 62.3 +/- 5.8 microM and 277.0 +/- 31.3 microM, respectively.

Structural and Functional Studies of Pavine N-Methyltransferase from Thalictrum flavum Reveal Novel Insights into Substrate Recognition and Catalytic Mechanism.[Pubmed:27573242]

J Biol Chem. 2016 Nov 4;291(45):23403-23415.

Benzylisoquinoline alkaloids (BIAs) are produced in a wide variety of plants and include many common analgesic, antitussive, and anticancer compounds. Several members of a distinct family of S-adenosylmethionine (SAM)-dependent N-methyltransferases (NMTs) play critical roles in BIA biosynthesis, but the molecular basis of substrate recognition and catalysis is not known for NMTs involved in BIA metabolism. To address this issue, the crystal structure of pavine NMT from Thalictrum flavum was solved using selenomethionine-substituted protein (dmin = 2.8 A). Additional structures were determined for the native protein (dmin = 2.0 A) as well as binary complexes with SAM (dmin = 2.3 A) or the reaction product S-adenosylhomocysteine (dmin = 1.6 A). The structure of a complex with S-adenosylhomocysteine and two molecules of tetrahydropapaverine (THP; one as the S conformer and a second in the R configuration) (dmin = 1.8 A) revealed key features of substrate recognition. Pavine NMT converted racemic THP to Laudanosine, but the enzyme showed a preference for (+/-)-pavine and (S)-reticuline as substrates. These structures suggest the involvement of highly conserved residues at the active site. Mutagenesis of three residues near the methyl group of SAM and the nitrogen atom of the alkaloid acceptor decreased enzyme activity without disrupting the structure of the protein. The binding site for THP provides a framework for understanding substrate specificity among numerous NMTs involved in the biosynthesis of BIAs and other specialized metabolites. This information will facilitate metabolic engineering efforts aimed at producing medicinally important compounds in heterologous systems, such as yeast.

Isolation and Characterization of O-methyltransferases Involved in the Biosynthesis of Glaucine in Glaucium flavum.[Pubmed:26297140]

Plant Physiol. 2015 Oct;169(2):1127-40.

Transcriptome resources for the medicinal plant Glaucium flavum were searched for orthologs showing identity with characterized O-methyltransferases (OMTs) involved in benzylisoquinoline alkaloid biosynthesis. Seven recombinant proteins were functionally tested using the signature alkaloid substrates for six OMTs: norlaudanosoline 6-OMT, 6-O-methyllaudanosoline 4'-OMT, reticuline 7-OMT, norreticuline 7-OMT, scoulerine 9-OMT, and tetrahydrocolumbamine OMT. A notable alkaloid in yellow horned poppy (G. flavum [GFL]) is the aporphine alkaloid glaucine, which displays C8-C6' coupling and four O-methyl groups at C6, C7, C3', and C4' as numbered on the 1-benzylisoquinoline scaffold. Three recombinant enzymes accepted 1-benzylisoquinolines with differential substrate and regiospecificity. GFLOMT2 displayed the highest amino acid sequence identity with norlaudanosoline 6-OMT, showed a preference for the 6-O-methylation of norlaudanosoline, and O-methylated the 3' and 4' hydroxyl groups of certain alkaloids. GFLOMT1 showed the highest sequence identity with 6-O-methyllaudanosoline 4'OMT and catalyzed the 6-O-methylation of norlaudanosoline, but more efficiently 4'-O-methylated the GFLOMT2 reaction product 6-O-methylnorlaudanosoline and its N-methylated derivative 6-O-methyllaudanosoline. GFLOMT1 also effectively 3'-O-methylated both reticuline and norreticuline. GFLOMT6 was most similar to scoulerine 9-OMT and efficiently catalyzed both 3'- and 7'-O-methylations of several 1-benzylisoquinolines, with a preference for N-methylated substrates. All active enzymes accepted scoulerine and tetrahydrocolumbamine. Exogenous norlaudanosoline was converted to tetra-O-methylated Laudanosine using combinations of Escherichia coli producing (1) GFLOMT1, (2) either GFLOMT2 or GFLOMT6, and (3) coclaurine N-methyltransferase from Coptis japonica. Expression profiles of GFLOMT1, GFLOMT2, and GFLOMT6 in different plant organs were in agreement with the O-methylation patterns of alkaloids in G. flavum determined by high-resolution, Fourier-transform mass spectrometry.

Unified Approach to Isoindolinones and THIQs via Lewis Acid Catalyzed Domino Mukaiyama-Mannich Lactamization/Alkylations: Application in the Synthesis of (+/-)-Homolaudanosine.[Pubmed:25992840]

Org Lett. 2015 Jun 5;17(11):2780-3.

A novel and efficient synthesis of a variety of isoindolinones and tetrahydroisoquinolines via a Lewis acid catalyzed domino Mukaiyama-Mannich lactamization/alkylation is achieved. This transformation comprises a sequential formation of three new bonds through a one-pot, three-component procedure to afford product in moderate to high yields. A concise synthesis of (+/-)-homoLaudanosine (2b) has been achieved using this method.

Organocatalytic enantioselective Pictet-Spengler approach to biologically relevant 1-benzyl-1,2,3,4-tetrahydroisoquinoline alkaloids.[Pubmed:25909585]

J Org Chem. 2015 May 15;80(10):5125-32.

A general procedure for the synthesis of 1-benzyl-1,2,3,4-tetrahydroisoquinolines was developed, based on organocatalytic, regio- and enantioselective Pictet-Spengler reactions (86-92% ee) of N-(o-nitrophenylsulfenyl)-2-arylethylamines with arylacetaldehydes. The presence of the o-nitrophenylsulfenyl group, together with the MOM-protection in the catechol part of the tetrahydroisoquinoline ring system, appeared to be a productive combination. To demonstrate the versatility of this approach, 10 biologically and pharmaceutically relevant alkaloids were prepared using (R)-TRIP as the chiral catalyst: (R)-norcoclaurine, (R)-coclaurine, (R)-norreticuline, (R)-reticuline, (R)-trimemetoquinol, (R)-armepavine, (R)-norprotosinomenine, (R)-protosinomenine, (R)-Laudanosine, and (R)-5-methoxyLaudanosine.

Capillary electrophoresis with electrochemiluminescence detection for the simultaneous determination of cisatracurium besylate and its degradation products in pharmaceutical preparations.[Pubmed:25872750]

J Sep Sci. 2015 Jul;38(13):2332-9.

Capillary electrophoresis with electrochemiluminescence detection for the simultaneous analysis of cisatracurium besylate and its degradation products (Laudanosine, quaternary monoacrylate) in pharmaceutical preparation was developed and fully validated. The significant parameters that influence capillary electrophoresis separation and electrochemiluminescence detection were optimized. The total analysis time of the analytes was 15 min. The linearities of the method were 0.1 approximately 40.0 mug/mL for cisatracurium besylate and 0.04 approximately 8.00 mug/mL for Laudanosine, with correlation coefficients (r) of 0.999 and 0.998, respectively. The detection limits (S/N = 3) were 83.0 ng/mL for cisatracurium besylate and 32.0 ng/mL for Laudanosine. The intraday relative standard deviations of the analytes were <3.0%, and the interday relative standard deviations were <8.0%. The developed method was cost-effective, sensitive, fast, and resource-saving, which was suitable for the ingredient analysis in pharmaceutical preparation.