Amanita muscaria (fly agaric): from a shamanistic hallucinogen to the search for acetylcholine.

The mushroom Amanita muscaria (fly agaric) is widely distributed throughout continental Europe and the UK. Its common name suggests that it had been used to kill flies, until superseded by arsenic. The bioactive compounds occurring in the mushroom remained a mystery for long periods of time, but eventually four hallucinogens were isolated from the fungus: muscarine, muscimol, muscazone and ibotenic acid. The shamans of Eastern Siberia used the mushroom as an inebriant and a hallucinogen. In 1912, Henry Dale suggested that muscarine (or a closely related substance) was the transmitter at the parasympathetic nerve endings, where it would produce lacrimation, salivation, sweating, bronchoconstriction and increased intestinal motility. He and Otto Loewi eventually isolated the transmitter and showed that it was not muscarine but acetylcholine. The receptor is now known variously as cholinergic or muscarinic. From this basic knowledge, drugs such as pilocarpine (cholinergic) and ipratropium (anticholinergic) have been shown to be of value in glaucoma and diseases of the lungs, respectively.

Characterisation of the membrane transport of pilocarpine in cell suspension cultures of Pilocarpus microphyllus.

Pilocarpine is an alkaloid obtained from the leaves of Pilocarpus genus, with important pharmaceutical applications. Previous reports have investigated the production of pilocarpine by Pilocarpus microphyllus cell cultures and tried to establish the alkaloid biosynthetic route. However, the site of pilocarpine accumulation inside of the cell and its exchange to the medium culture is still unknown. Therefore, the aim of this study was to determine the intracellular accumulation of pilocarpine and characterise its transport across membranes in cell suspension cultures of P. microphyllus. Histochemical analysis and toxicity assays indicated that pilocarpine is most likely stored in the vacuoles probably to avoid cell toxicity. Assays with exogenous pilocarpine supplementation to the culture medium showed that the alkaloid is promptly uptaken but it is rapidly metabolised. Treatment with specific ABC protein transporter inhibitors and substances that disturb the activity of secondary active transporters suppressed pilocarpine uptake and release suggesting that both proteins may participate in the traffic of pilocarpine to inside and outside of the cells. As bafilomicin A1, a specific V-type ATPase inhibitor, had little effect and NH4Cl (induces membrane proton gradient dissipation) had moderate effect, while cyclosporin A and nifedipine (ABC proteins inhibitors) strongly inhibited the transport of pilocarpine, it is believed that ABC proteins play a major role in the alkaloid transport across membranes but it is not the exclusive one. Kinetic studies supported these results.

Induction of pilocarpine formation in jaborandi leaves by salicylic acid and methyljasmonate.

Jaborandi seedlings were subjected to different treatments in order to study the induction of pilocarpine in the leaves. In addition four extraction methods were assessed to extract the alkaloid from dried leaves. The highest yielding extraction and recovery was observed when dried leaves were first treated with base and then extracted with chloroform. Salt stress (NaCl), wounding, hypoxia, and N and K omission of the nutrient soln caused reductions in pilocarpine contents. Whereas complete nutrient soln and P omission maintained normal levels of the alkaloid. Salicylic acid and methyljasmonate induced a 4-fold increase of pilocarpine, but this increase was dependent on the concentration and time after exposure.

Synthesis and analysis of O,O'-dicarboxylate (dibenzyl) bispilocarpates as possible prodrugs of pilocarpine.

As a part of a series of studies to develop prodrug derivatives of pilocarpine, the O,O'-succinyl (dibenzyl), O,O-adipoyl (dibenzyl), O,O-fumaryl (dibenzyl), and O,O-terephthaloyl (dibenzyl) bispilocarpate fumarates were synthesized as a new class of pilocarpine prodrugs. The compounds were prepared from pilocarpic acid benzyl monoester by coupling two pilocarpic acid benzyl monoesters together with spacer chains by usual esterification methods. Liquid chromatography, thermospray liquid chromatography-mass spectrometry, high-resolution mass spectrometry, and NMR spectroscopy were applied to the identification and the purity evaluation of the synthetic products.

Problems connected with HPLC separation of pilocarpine from its degradation products by means of silica gel and water-based mobile phase.

HPLC separation of pilocarpine from its degradation products (isopilocarpine, pilocarpic acid and isopilocarpic acid) was studied on unmodified silica gel stationary phase. An acidified aqueous solution of inorganic salts with addition of methanol served as the mobile phase. The influence of silica gel used, methanol content, mobile phase pH, anion of acids and/or inorganic salts and column temperature on solute retention, separation selectivity as well as peak shape was studied and partly explained. A significant dependence of the properties of the resulting separation system on the silica gel used was found. A test was proposed for evaluation of silica gel suitability.

Effect of pH on charcoal adsorption of lidocaine, methadone, pilocarpine, and procaine.

The charcoal adsorption from aqueous solution of four weak bases (lidocaine, methadone, pilocarpine, and procaine) was studied at a variety of pH values representing large differences in percent ionization. The measure of charcoal adsorption used was percent of the ligand adsorbed (constant starting ligand concentrations of 3 X 10(-4) M) by a variety of quantities of charcoal ranging from 3 to 30 mg per 10 mL of mixture. In addition, moles of ligand adsorbed/gram of charcoal values were calculated. The data indicated that for a given ligand, charcoal adsorption was statistically the same (p = 0.05) at all pH values. It is concluded that the generalization for weak bases that charcoal adsorption increases with increasing pH may not be universally valid.

Separation and analysis of pilocarpine, isopilocarpine, and pilocarpic acid by reverse phase liquid chromatography: collaborative study.

A method for separating and determining pilocarpine and 2 degradation products was developed and subjected to collaborative study. Pilocarpine, isopilocarpine, and pilocarpic acid were isolated on a reverse phase liquid chromatographic phenyl bonded column and detected by UV spectrophotometry at 220 nm. Nine collaborators received commercial samples labeled to contain 2, 1, and 0.5% pilocarpine and a 2% practice sample. The collaborative results for pilocarpine were excellent; coefficients of variation ranged from 3.20 to 4.10%. The method was adopted official first action for determination of the active component, pilocarpine, in the presence of isopilocarpine and pilocarpic acid. Although quantitative results for the degradation products were not as good, the method is suitable as a limits test for these substances.

Synthesis of d-pilocarpine-N-14CH3.

The total synthesis of d-pilocarpine specifically labeled as N-14CH3 is reported. dl-Homopilopic acid was prepared as a key intermediate and resolved into the d-enantiomer via the alpha-methylbenzylamine salt. The penultimate intermediate, 2-mercaptopilocarpine, was desulfurized by oxidation with dilute hydrogen peroxide, minimizing isomerization to isopilocarpine. Procedures for the analysis of pilocarpine-isopilocarpine mixtures by high-pressure liquid chromatography are also described.