A Review of Synthetic Access to Therapeutic Compounds Extracted from Psilocybe

Psychedelics are used for various pathologies of the central nervous system and are currently the subject of much research, some of which relates to the compounds contained in various Psilocybe-type hallucinogenic mushrooms. It is difficult, however, to obtain and purify sufficient quantities of these compounds from fungi to carry out biological studies, hence the need to develop simple and efficient synthetic routes. We review here the various syntheses used to obtain these molecules, focusing first on the classic historical syntheses, then the use of more recent metallo-catalyzed couplings and finally the known biocatalytic methods for obtaining these molecules. Other access routes are certainly possible and should be the subject of future research given the therapeutic interest of these compounds.

Enzymatic Strategy for the Resolution of New 1-Hydroxymethyl Tetrahydro-β-carboline Derivatives in Batch and Continuous-Flow Systems

Many alkaloids containing a tetrahydro‐β‐carboline skeleton have well‐known therapeutic effects, leading to increased interest in the synthesis of these natural products. Enantiomers of N‐Boc‐protected 1‐hydroxymethyl‐1,2,3,4‐tetrahydro‐β‐carboline [(±)‐7], 1‐hydroxymethyl‐6‐methoxy‐1,2,3,4‐tetrahydro‐β‐carboline [(±)‐8], and 1‐hydroxymethyl‐6‐fluoro‐1,2,3,4‐tetrahydro‐β‐carboline [(±)‐9] were prepared through enzymecatalyzed asymmetric acylation of their primary hydroxyl group. The preliminary experiments were performed in a continuous‐flow system, while the preparative‐scale resolutions were done as batch reactions. Excellent enantioselectivities (E>200) were obtained with Candida antarctica lipase B (CAL‐B) and acetic anhydride in toluene at 60 °C. The recovered alcohols and the produced esters were obtained with high enantiomeric excess values (ee≥96 %). The O‐acylated enantiomers [(S)‐10–(S)‐12)] were transformed into the corresponding amino alcohols [(S)‐7–(S)‐9)] with methanolysis. Microwave‐assisted Boc removals were also performed and resulted in the corresponding compounds (R)‐4–(R)‐6 and (S)‐4–(S)‐6 without a drop in the enantiomeric excess values (ee≥96 %).

Recent pharmacological developments in β-carboline alkaloid "harmaline"

Peganum harmala (L) is a perennial plant which is native of eastern Iranian and west of India but also found in different regions of western USA. A number of β-carboline compounds with therapeutic importance and different pharmacological effects, are present in this plant. Among other alkaloids, such as, harmine, harmalol and vasicine, isolated from various parts of the plant, harmaline is considered as most valuable with reference to its medicinal importance. Harmaline has been extensively studied in last decade and known to exert multiple pharmacological effects including antileishmanial, antimicrobial, antiplatelet, antiplasmodial, antitumoral, hypothermic and vasorelaxant activity. The proposed work is intended to highlight the recent pharmacological aspects of β-carboline alkaloid "harmaline".

Tetrahydro-beta-carboline carboxylic acids in smoked foods

This paper reports for the first time in smoked foods the presence of three tetrahydro-beta-carboline carboxylic acids. One of these, 1-hydroxymethyl-tetrahydro-beta-carboline-3-carboxylic acid, which is derived from the interaction of tryptophan and glycolaldehyde, and which has not previously been reported in foods, was observed in 20 samples at levels up to 444 micrograms/kg. The corresponding products which are derived from tryptophan and formaldehyde or tryptophan and acetaldehyde were found respectively in 28 samples at levels up to 22 mg/kg and in 16 samples at levels up to 881 micrograms/kg. Greater concentrations were generally found in those smoked foods having a lower pH value and produced by using a longer fermentation or maturation. Only 1-methyl-tetrahydro-beta-carboline carboxylic acid (156-574 micrograms/kg) was found in the four unsmoked samples analysed.

Concentrations of tryptoline and methtryptoline in rat brain

Combined gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry have been used to identify and quantify tryptoline, methtryptoline, 5-hydroxytryptoline, and 5-hydroxymethtryptoline as their heptafluorobutyryl derivatives in extracts of rat brain. Tryptoline and methtryptoline were identified on the basis of their retention times and mass spectral characteristics: they were reliably detected in brain tissue extracts without interference from artifactual formation; their whole brain concentrations ranged between 0.2 and 3 ng/g; and they had a similar neuroanatomical distribution, with the highest concentrations in the cerebellum and the cortex. Smaller quantities of 5-hydroxytryptoline and 5-hydroxymethtryptoline were also identified on the basis of their retention times and mass spectral characteristics. However, the significance of this finding is unclear, because these two compounds were accompanied by larger quantities of their tetradeuterated analogues formed from tetradeuterated-5-hydroxytryptamine added at the time of tissue homogenization; this result suggests that formation of 5-hydroxytryptoline and 5-hydroxymethtryptoline occurred during tissue homogenization, sample preparation, or both.

Rapid hydroxylation of methtryptoline (1-methyltetrahydro-beta-carboline) in rat: identification of metabolites by chiral gas chromatography-mass spectrometry

Racemic methtryptoline (1-methyltetrahydro-beta-carboline) and 5-hydroxymethtryptoline-9-carboxylic acid (6-hydroxy-1-methyltetrahydro-beta-carboline-1-carboxylic acid) were administered intraperitoneally to rats and the components of their urine was subsequently investigated by chiral gas chromatography-mass spectrometry. Methtryptoline rapidly became hydroxylated in the 5- and 6-position and excreted in urine. There was about a ninefold predominance of the S(-) enantiomer over the other in the 5-hydroxylated species, while the 6-hydroxylation produced a small excess of the R(+) enantiomer. About 75% of the injected dose of methtryptoline was recovered in the urine as 5- and 6-hydroxylated compounds during the first 24 h period, demonstrating that hydroxylation represents the major metabolic pathway. Treatment with 6-hydroxymethtryptoline-9-carboxylic acid led to a fivefold increase in the urinary excretion of 5-hydroxymethtryptoline during the first 24 h period with a predominance of the S(-)-enantiomer, indicating a much smaller conversion rate than from methtryptoline. It was concluded that hydroxylation of methtryptoline is a likely pathway for the natural formation of 5-hydroxymethtryptoline.