Chemoenzymatic Synthesis of 5-Methylpsilocybin: A Tryptamine with Potential Psychedelic Activity

Characterization of the Gateway Decarboxylase for Psilocybin Biosynthesis

The l-tryptophan decarboxylase PsiD catalyzes the initial step of the metabolic cascade to psilocybin, the major indoleethylamine natural product of the "magic" mushrooms and a candidate drug against major depressive disorder. Unlike numerous pyridoxal phosphate (PLP)-dependent decarboxylases for natural product biosyntheses, PsiD is PLP-independent and resembles type II phosphatidylserine decarboxylases. Here, we report on the in vitro biochemical characterization of Psilocybe cubensis PsiD along with in silico modeling of the PsiD structure. A non-canonical serine protease triad for autocatalytic cleavage of the pro-protein was predicted and experimentally verified by site-directed mutagenesis.

Indole-Containing Natural Products 2019-2022: Isolations, Reappraisals, Syntheses, and Biological Activities

Indole alkaloids represent a large subset of natural products, with more than 4100 known compounds. The majority of these alkaloids are biologically active, with some exhibiting excellent antitumor, antibacterial, antiviral, antifungal, and antiplasmodial activities. Consequently, the natural products of this class have attracted considerable attention as potential leads for novel therapeutics and are routinely isolated, characterized, and profiled to gauge their biological potential. However, data on indole alkaloids, their various structures, and bioactivities are complex due to their diverse sources, such as plants, fungi, bacteria, sponges, tunicates, and bryozoans; thus, isolation methods produce an incredible trove of information. The situation is exacerbated when synthetic derivatives, as well as their structures, bioactivities, and synthetic schemes, are considered. Thus, to make such data comprehensive and inform researchers about the current field's state, this review summarizes recent reports on novel indole alkaloids. It deals with the isolation and characterization of 250 novel indole alkaloids, a reappraisal of previously reported compounds, and total syntheses of indole alkaloids. In addition, several syntheses and semi-syntheses of indole-containing derivatives and their bioactivities are reported between January 2019 and July 2022.

Structure Elucidation and Spectroscopic Analysis of Chromophores Produced by Oxidative Psilocin Dimerization

Psilocin (1) is the dephosphorylated and psychotropic metabolite of the mushroom natural product psilocybin. Oxidation of the phenolic hydroxy group at the C-4 position of 1 results in formation of oligomeric indoloquinoid chromophores responsible for the iconic blueing of bruised psilocybin-producing mushrooms. Based on previous NMR experiments, the hypothesis included that the 5,5'-coupled quinone dimer of 1 was the primary product responsible for the blue color. To test this hypothesis, ring-methylated 1 derivatives were synthesized to provide stable analogs of 1 dimers that could be completely characterized. The chemically oxidized derivatives were spectroscopically analyzed and compared to computationally derived absorbance spectra. Experimental evidence did not support the original hypothesis. Rather, the blue color was shown to stem from the quinoid 7,7'-coupled dimer of 1.