What is the form of muscimol from fly agaric mushroom (Amanita muscaria) in water? An insight from NMR experiment supported by molecular modeling

The biologically active alkaloid muscimol is present in fly agaric mushroom (Amanita muscaria), and its structure and action is related to human neurotransmitter _γ -aminobutyric acid (GABA). The current study reports on determination of muscimol form present in water solution using multinuclear ¹ H and ¹³ C nuclear magnetic resonance (NMR) experiments supported by density functional theory molecular modeling. The structures of three forms of free muscimol molecule both in the gas phase and in the presence of water solvent, modeled by polarized continuous model, and nuclear magnetic isotropic shieldings, the corresponding chemical shifts, and indirect spin-spin coupling constants were calculated. Several J-couplings observed in proton and carbon NMR spectra, not available before, are reported. The obtained experimental spectra, supported by theoretical calculations, favor the zwitterion form of muscimol in water. This structure differs from NH isomer, previously determined in dimethyl sulfoxide (DMSO) solution. In addition, positions of signals C3 and C5 are reversed in both solvents.

Effects of Amanita muscaria extract on different in vitro neurotoxicity models at sub-cellular and cellular levels

Muscimol is the main compound found in Amanita muscaria. Several studies have proven that muscimol has suppressive effects on essential tremor, without impairing speech and coordination. The effects of muscimol in Parkinson-affected patients is also described in a number of studies. These studies describe the free radical scavenging and antioxidant activity of the mushroom extract. We have evaluated the possible neuroprotective effects of a standardized extract from A. muscaria, containing high amounts of muscimol, on different models of neurotoxicity in rat brain microsomes, mitochondria, synaptosomes as well as on neuroblastoma cell line SH-SY5Y. The possible inhibitory effect on human recombinant monoaminoxidase-B (hMAOB) enzyme was also studied. The extract revealed statistically significant neuroprotective effects on the in vitro neurotoxicity models and no inhibitory activity on hMAOB.

Catching flies with Amanita muscaria: traditional recipes from Slovenia and their efficacy in the extraction of ibotenic acid

ETHNOPHARMACOLOGICAL RELEVANCE

Fly control is necessary for maintaining good hygiene on farms. Because organic farmers are skeptical about chemical pesticides, alternative fly control remedies are being considered. Amanita muscaria is a widespread fungus that contains ibotenic acid and muscimol. This fungus has been used to catch flies for centuries, but traditional recipes are poorly described, documented and characterized.

AIM OF THE STUDY

The aim of the present study was to collect the traditional methods for preparing A. muscaria for catching flies in Karst and Gorjanci and to investigate the influence of different traditional methods on the release of ibotenic acid and muscimol from the fungal material.

MATERIALS AND METHODS

The research was conducted in villages in Karst and in the foothills of Gorjanci, Slovenia. Data regarding the traditional recipes of A. muscaria for catching flies were collected through structured interviews with 31 people in Karst and 28 in Gorjanci. Eight preparations were prepared based on traditional methods, and the amount of ibotenic acid and muscimol released from the fungal material at five different time points (0.5, 1, 2, 3 and 24h) was determined by high-performance liquid chromatography (HPLC).

RESULTS

Detailed descriptions of preparations used for catching flies were obtained from three informants in Karst, who were originally from other parts of Slovenia, and 13 informants in the foothills of Gorjanci. However, there were no reports regarding current usage. A total of 9 different methods were collected. Some methods were simple and included soaking in milk or water or dripping a little milk onto the mushroom. Others were more complex and included a combination of heat or mechanical processing and soaking in milk or water. For all preparations, the release of ibotenic acid was time-dependent, with the extracted amount increasing over time. Although milk was used more often than water in the traditional recipes, the release of both substances was not dependent on the solvent used. Fungal material that was exclusively soaked in water or milk released the smallest amount of ibotenic acid and muscimol at each time point. Additional heat and mechanical processing led to faster release of ibotenic acid and muscimol from the fungal material.

CONCLUSIONS

The tradition of using A. muscaria for catching flies was present in Gorjanci but not in Karst. The methods used to prepare the fungal material vary, and these differences are reflected in the release profile of ibotenic acid.

Hallucinogens and dissociative agents naturally growing in the United States

It is usually believed that drugs of abuse are smuggled into the United States or are clandestinely produced for illicit distribution. Less well known is that many hallucinogens and dissociative agents can be obtained from plants and fungi growing wild or in gardens. Some of these botanical sources can be located throughout the United States; others have a more narrow distribution. This article reviews plants containing N,N-dimethyltryptamine, reversible type A monoamine oxidase inhibitors (MAOI), lysergic acid amide, the anticholinergic drugs atropine and scopolamine, or the diterpene salvinorin-A (Salvia divinorum). Also reviewed are mescaline-containing cacti, psilocybin/psilocin-containing mushrooms, and the Amanita muscaria and Amanita pantherina mushrooms that contain muscimol and ibotenic acid. Dangerous misidentification is most common with the mushrooms, but even a novice forager can quickly learn how to properly identify and prepare for ingestion many of these plants. Moreover, through the ever-expanding dissemination of information via the Internet, this knowledge is being obtained and acted upon by more and more individuals. This general overview includes information on the geographical range, drug content, preparation, intoxication, and the special health risks associated with some of these plants. Information is also offered on the unique issue of when bona fide religions use such plants as sacraments in the United States. In addition to the Native American Church's (NAC) longstanding right to peyote, two religions of Brazilian origin, the Santo Daime and the Uniao do Vegetal (UDV), are seeking legal protection in the United States for their use of sacramental dimethyltryptamine-containing "ayahuasca."

GABA agonists. Resolution, absolute stereochemistry, and enantioselectivity of (S)-(+)- and (R)-(-)-dihydromuscimol

(RS)-5-(Aminomethyl)-2-isoxazolin-3-ol (dihydromuscimol, DHM) is a potent 4-aminobutyric acid (GABA) agonist, the inhibitory effects of which on neurons are sensitive to the antagonist bicuculline methochloride (BMC), and it also interacts with the GABA uptake system in vitro. (S)-(+)-DHM (4) and (R)-(-)-DHM (5) were obtained in optically pure forms via resolution of tert-butyloxycarbonyl-protected DHM (1) using cinchonidine as the only resolving agent. The optical purity and absolute stereochemistry of 4 and 5 were established by chemical correlation to the (S)-(+) enantiomer of 3-hydroxy-4-aminobutyric acid (GABOB). While 4 was a specific and potent BMC-sensitive GABA agonist in vivo and in vitro, possibly the most potent GABA agonist so far described, the inhibition of GABA uptake by DHM proved to reside exclusively in the (R)-(-) enantiomer (5). The affinity of 5 for BMC-sensitive GABA receptor sites in vitro was some 50 times lower than that of 4. Compounds 4 and 5 can be considered semirigid isosteres of the conformationally flexible GABA analogues (S)-(+)- and (R)-(-)-GABOB, respectively, which show a very low degree of enantioselectivity with respect to GABA synaptic mechanisms. This correlation between the degree of enantioselectivity and conformational mobility of chiral GABA analogues might be of importance for the design of new drugs with specific actions at synapses at which GABA is the transmitter.

Excitatory amino acids: studies on the biochemical and chemical stability of ibotenic acid and related compounds

The complex pharmacological profile (excitation/inhibition) of ibotenic acid on single neurons in the mammalian CNS prompted studies on the stability of ibotenic acid and a number of structurally related excitatory amino acids under different in vitro conditions in the presence or absence of enzymes. Ibotenic acid, (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-7-carboxylic acid (7-HPCA), (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and (RS)-alpha-amino-3-hydroxy-4-bromo-5-isoxazolepropionic acid (4-Br-homoibotenic acid) were all inhibitors of (S)-glutamic acid decarboxylase (GAD) in mouse brain homogenates, but only ibotenic acid was shown to undergo decarboxylation during incubation with brain homogenates. The formation of the decarboxylated product, muscimol, which primarily occurred in a synaptosomal fraction, was dependent on the presence of pyridoxal-5-phosphate (PALP) and was inhibited by (S)-glutamic acid, 3-mercaptopropionic acid (3MPA), aminooxyacetic acid (AOAA), and allyglycine, suggesting that ibotenic acid is a substrate for GAD. The overall decomposition rate for ibotenic acid (8.7 nmol min-1 mg-1 of protein), which apparently embraces other reactions in addition to decarboxylation to muscimol, was higher than the rate of decarboxylation of (S)-glutamic acid (3.2 nmol min-1 mg-1 of protein). At pH 7.4 and 37 degrees C, but in the absence of enzymes, none of the excitatory amino acids under study underwent any detectable decomposition, whereas ibotenic acid and 7-HPCA, but not AMPA and 4-Br-homoibotenic acid, decomposed, partially by decarboxylation, at 100 degrees C in a pH-dependent manner. In the presence of liver homogenates, ibotenic acid was also shown to decompose.(ABSTRACT TRUNCATED AT 250 WORDS)