C. Psilocybin
Synonym Indocybin;
Biological Sources These are same as mentioned in psilocin ‘B’ above.
Chemical Structure
3-[2-(Dimethylamino) ethyl]-1H-indol-4-ol dihydrogen phosphate ester; (C12H17N2O4P).
Isolation The method of isolation of psilocybin is the same as stated under psilocin.
Characteristic Features
1. Psilocybin is obtained as crystals from boiling water having mp 220-228°C; and from boiling methanol mp 185-195°C.
2. It has uvmax (methanol): 220, 267, 290 nm (log ε 4.6, 3.8, 3.6).
3. The pH of a saturated solution in 50% aqueous ethanol is 5.2.
4. Solubility Profile: It is soluble in 20 parts of boiling water, 120-parts of boiling methanol; sparingly soluble in ethanol; and practically insoluble in chloroform, benzene.
Uses It is a hallucinogenic substance and exerts its action at a dose level of 6-20 mg.
Biosynthesis of Serotonin, Psilocin and Psilocybin The different steps involved in the biosynthesis of serotonin, psilocin and psilocybin may be summarized as stated below:
1. L-Tryptophan upon oxidation gives rise to the corresponding hydroxylated derivative known as 5-hydroxyl-L-tryptophan, which further undergoes decarboxylation to yield serotonin also termed as 5-hydroxytryptamine (or 5-HT).
2. L-Tryptophan undergoes decarboxylation to yield the tryptamine, which affords N-Methylation and N,N-dimethylation in the presence of S-adenosylmethionine (SAM). The resulting dimethyl derivative upon oxidation gives rise to the product psilocin another hydroxylated derivative.
3. Phosphorylation of the hydroxyl function in psilocin affords psilocybin.
4. Interestingly, both psilocin and psilocybin are solely responsible for attributing the hallucinogenic properties of the so-called ‘magic mushrooms’, that include species of Psilocybe, Panaeolus and the like.
* Hofmann et al., Experientia, 14, 107 (1958); Heim et al., Helv. Chim. Acta, 42, 1557 (1959).
