Psilocin and Psilocybin in Fungi

Determination of the indole alkaloids psilocin and psilocybin in fungi has been the most popular application of EC in the analysis of alkaloids in a plant matrix. This research has primarily been done by two groups Christiansen and co-workers in Norway, and Kysilka and Wurst in the Czech Republic. Especially psilocin is well suited for EC, due to its hydroxy substituent on the indole ring, essentially a phenol, whereas in psilocybin this group is phosphorylated. Since the pH of the mobile phase is not critical to the oxidation of either the phenolic group or indole nucleus, it has been possible to use different separation techniques. 

Christiansen et al. developed an HPLC method of screening Norwegian mushrooms for the presence of psilocin and psilocybin. The alkaloids were extracted from powdered dried mushrooms with methanol which contained 10% IN ammonium nitrate (Christiansen et al. 1981). The recovery of psilocybin was at least 98%, whereas the recovery of psilocin was not reported. The analytes were separated on an unmodified silica column using an alkaline eluent (Christiansen and Rasmussen 1983). After separation, the effluent was split to UV and FL detectors, and an EC detector was connected downstream of the UV detector. Psilocybin was identified and determined by both UV and FL detection. EC was optimized for psilocin due to its low concentration in the mushroom. The detection limit of psilocin by EC was 100 and 250 times lower than by UV and FL, respectively. Psilocybin gave only a small response by EC, since it is optimally oxidized at a higher potential. By this method, it was found that Conocybe cyanopus and Pluteus salicinus also contained psilocin and psilocybin (Christiansen et al. 1984). 

Kysilka and Wurst have studied the biosynthesis of psilocin and psilocybin in mushrooms for many years. Recently, they thoroughly studied the extraction of psilocin and psilocybin and found that different extraction systems must be used for each alkaloid (Kysilka and Wurst 1990). Psilocin was extracted with best recovery by ethanol water (3 1) and psilocybin by methanol water (3 1) saturated with potassium nitrate. The recoveries of psilocin and psilocybin were about 10 and 1.3 times higher, respectively, than with just methanol extraction for Psilocybe bohemica. These researchers also used a separation technique different from that of Christiansen s group. Psilocin and psilocybin were eluted on a reversed- 

Analyte Matrix Column Mobile phase CelF Potential s Detection limit d (ng) Reference 

Castanospermine Leaves Dionex CSS 0.01 M HCl post-column addition of 0.3 M NaOH PAD +0.05 0.75 Donaldson et al. (1990) 

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