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Robert B. Kargbo

Usona Institute

41 papers in the library · 427 citations · publishing 2019-2026

Papers

Synthesis and Biological Evaluation of Tryptamines Found in Hallucinogenic Mushrooms: Norbaeocystin, Baeocystin, Norpsilocin, and Aeruginascin

Journal of Natural Products February 20, 2020 Alexander M. Sherwood, Adam L. Halberstadt, Adam K. Klein et al. 79 citations

A new synthetic method allows access to tryptamine natural products found in psilocybin-producing mushrooms. Laboratory and animal experiments tested whether these compounds are psychoactive. In mice, the natural product baeocystin did not produce a head twitch response, a behavioral marker of psychedelic activity, even though its predicted breakdown product, norpsilocin, strongly activates the 5-HT2A receptor, which is associated with psychedelic effects. This suggests that baeocystin itself may not be psychedelic, despite its metabolite's activity.

Psilocybin Therapeutic Research: The Present and Future Paradigm

ACS Medicinal Chemistry Letters March 2, 2020 Robert B. Kargbo 48 citations

Psilocybin, the active component in magic mushrooms, may offer therapeutic benefits for conditions like major depressive disorder and addiction without the addictiveness or overdose risk of drugs such as cocaine, heroin, alcohol, and methamphetamine. The need for new treatments is urgent due to rising rates of addiction, overdose, and suicide in the United States and worldwide. Anecdotal and contemporary pharmacological reports suggest psilocybin's potential for treating mental health disorders. This Viewpoint summarizes current psilocybin therapeutic research and offers insights into future directions for scientific focus.

Scalable Hybrid Synthetic/Biocatalytic Route to Psilocybin

Chemistry - A European Journal February 26, 2020 Janis Fricke, Robert B. Kargbo, Lars Regestein et al. 48 citations

Psilocybin, the main psychoactive alkaloid in Psilocybe mushrooms, is being tested as a treatment for depression. Pharmaceutical psilocybin is currently made by synthetic chemistry. Replacing a difficult chemical phosphorylation step with the mushroom enzyme PsiK allowed production of one gram of psilocybin from psilocin in 20 minutes. A pilot-scale protocol also yielded 150 mg of active, soluble PsiK enzyme. This combination of tryptamine chemistry and enzymatic catalysis may provide access to psilocybin at potentially lower cost.

Direct Phosphorylation of Psilocin Enables Optimized cGMP Kilogram-Scale Manufacture of Psilocybin

ACS Omega July 1, 2020 Jessica Sable, Tura Patterson, Gary Tarpley et al. 41 citations

A new chemical process produces over one kilogram of high-purity psilocybin, the active compound in psychedelic mushrooms, using a second-generation synthesis designed for large-scale manufacturing. The method improves on earlier procedures by optimizing the Speeter-Anthony tryptamine synthesis to create the intermediate psilocin with better control and impurity removal. It then directly phosphorylates psilocin with phosphorous oxychloride, avoiding a complex benzyl-protecting group strategy used in previous methods. This approach addresses challenges in yield, purity, atom economy, and suitability for pilot plant-scale reactors, providing a more efficient and consistent route for producing psilocybin under current Good Manufacturing Practices.

Taking Different Roads: l‐Tryptophan as the Origin of Psilocybe Natural Products

ChemPlusChem October 1, 2020 Claudius Lenz, Alexander M. Sherwood, Robert B. Kargbo et al. 40 citations

Psilocybe fungi, known as magic mushrooms, produce psilocybin from the amino acid L-tryptophan. Recent research shows these fungi have a more varied secondary metabolism derived from this amino acid. This review describes psilocybin and related compounds, including blue-colored psilocyl oligomers, beta-carbolines, and N,N-dimethyl-L-tryptophan, along with current knowledge of their biosynthesis. The work covers pharmacological, medicinal, ecological, biochemical, and evolutionary aspects of these natural products.

Enzymatic Route toward 6‐Methylated Baeocystin and Psilocybin

ChemBioChem May 31, 2019 Janis Fricke, Alexander M. Sherwood, Robert B. Kargbo et al. 38 citations

Psilocybin and its precursor baeocystin are indole alkaloids from psychotropic Psilocybe mushrooms, currently under clinical investigation for depression and anxiety. A biocatalytic route was developed to synthesize 6-methylated psilocybin and baeocystin from 4-hydroxy-6-methyl-L-tryptophan, using the Psilocybe cubensis enzymes PsiD and PsiK for decarboxylation and phosphorylation, and PsiM for N-methylation. An in silico structural model of PsiM revealed a well-conserved SAM-binding core with peripheral nonconserved elements that likely determine substrate preferences.

An Improved, Practical, and Scalable Five-Step Synthesis of Psilocybin

Synthesis January 8, 2020 Robert B. Kargbo, Alexander M. Sherwood, Poncho Meisenheimer et al. 31 citations

An improved chemical synthesis of psilocybin produces multigram quantities in five steps with 23% overall yield from an inexpensive acetoxyindole starting material. The protocol identifies critical in-process parameters and isolates psilocybin without chromatography, thin-layer chromatography, or aqueous workup. The procedure emphasizes process control and impurity fate and removal to deliver high-quality psilocybin.

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

Journal of Natural Products March 5, 2021 Janis Fricke, Alexander M. Sherwood, Adam L. Halberstadt et al. 18 citations

A novel analogue of psilocybin, 5-methylpsilocybin, was produced through a hybrid chemoenzymatic synthesis, combining chemical synthesis of 5-methylpsilocin with enzymatic phosphorylation using a purified kinase from Psilocybe cubensis. The product was isolated with high purity via solvent-antisolvent precipitation. In a mouse head-twitch response assay, 5-methylpsilocybin showed psychedelic-like activity more potent than dimethyltryptamine but less potent than psilocybin.

Microbiome–Gut–Brain Axis Modulation: New Approaches in Treatment of Neuropsychological and Gastrointestinal Functional Disorders

ACS Medicinal Chemistry Letters May 11, 2023 Robert B. Kargbo 15 citations

The gut-brain axis (GBA) is a bidirectional communication system linking the digestive system and the central nervous system through neuro-immune and hormonal pathways. The gut microbiome plays a key role in this communication, influencing mental health. This Patent Highlight describes methods to promote colonization of spore-forming bacteria in the gastrointestinal tract by administering serotonin receptor agonists, including psychedelic compounds such as psilocybin, psilocin, N,N-dimethyltryptamine, bufotenine, 5-methoxy-N,N-dimethyltryptamine, lysergic acid diethylamide, ergine, mescaline, 3,4-methylenedioxyamphetamine, and 2,5-dimethoxy-4-methylamphetamine.

5-MeO-DMT: Potential Use of Psychedelic-Induced Experiences in the Treatment of Psychological Disorders

ACS Medicinal Chemistry Letters October 21, 2021 Robert B. Kargbo 15 citations

5-MeO-DMT, a potent psychedelic, may be useful in treating psychological disorders by inducing profound experiences that facilitate therapeutic breakthroughs. The article discusses how psychedelic-induced experiences could help patients with conditions such as depression, anxiety, and addiction by promoting neuroplasticity and emotional processing. It highlights the potential of 5-MeO-DMT to produce rapid and sustained improvements in mental health, though further research is needed to understand its mechanisms and optimize therapeutic protocols. The work emphasizes the importance of set and setting in maximizing therapeutic outcomes and minimizing risks.

Tryptamines and Mental Health: Activating the 5-HT Receptor for Therapeutic Potential

ACS Medicinal Chemistry Letters September 15, 2023 Robert B. Kargbo 11 citations

Tryptamines, which activate serotonin receptors, are being investigated as potential treatments for mental health disorders. The FDA has designated psilocybin and MDMA as breakthrough therapies for conditions like treatment-resistant depression, major depressive disorder, and PTSD. Clinical trials show significant improvements in patient-reported outcomes through reductions in experiential avoidance, indicating a promising future for these compounds in mental health therapy.

Psilocybin: crystal structure solutions enable phase analysis of prior art and recently patented examples

Acta Crystallographica Section C Structural Chemistry December 20, 2021 Alexander M. Sherwood, Robert B. Kargbo, Kristi W. Kaylo et al. 10 citations

Psilocybin, a natural product from psychoactive fungi, exists in three distinct crystal forms: Hydrate A, Polymorph A, and Polymorph B. This article presents newly solved crystal structures for the two anhydrate forms using X-ray diffraction and computational methods. Analysis of psilocybin samples produced between 1963 and 2021 shows that all contain one or more of these three forms, with no additional forms needed to explain their diffraction patterns. The composition correlates with process methods, sample age, and storage conditions. The authors also identify that a recently granted patent incorrectly described a mixture of about 81% Polymorph A and 19% Polymorph B as a single-phase variant, recommending revision of such characterizations.

Microbiome: The Next Frontier in Psychedelic Renaissance

Journal of Xenobiotics July 25, 2023 Robert B. Kargbo 5 citations

The gut microbiome may influence how individuals respond to psychedelic substances used in therapy. This review examines the gut–brain axis and its effects on mood, cognition, and behavior, and discusses how microbiome variations could affect the metabolism and bioavailability of psychedelics. It also considers microbiome-targeted interventions as a potential way to enhance psychedelic therapy's effectiveness. By integrating psychopharmacology, microbiology, and neuroscience, the authors aim to advance understanding of the microbiome-psychedelic relationship and optimize mental health outcomes in the current psychedelic renaissance.

Psilocybin: Characterization of the Metastable Zone Width (MSZW), Control of Anhydrous Polymorphs, and Particle Size Distribution (PSD)

ACS Omega February 7, 2022 Robert B. Kargbo, Alexander M. Sherwood, Poncho Meisenheimer et al. 5 citations

A thermodynamically controlled crystallization process for psilocybin, a serotonergic agonist granted breakthrough therapy status for depression, produces crystals with stronger interactions, a controlled particle size distribution, and an improved impurity profile compared to a faster, kinetically controlled process that yields smaller particles. Real-time monitoring with high-resolution inline microscopy measured particle size and metastable zone width and nucleation induction. Water recrystallization forms polymorph B (trihydrate) independently of the method, while polymorph A (anhydrate) and polymorph H (anhydrate) depend on drying: room-temperature vacuum drying yields mainly polymorph A, and heating even at low temperatures produces a mixture of polymorphs A and H.

Orally Active Forms of DMT, 5-MeO-DMT, and Long-Acting MDMA for the Treatment of Neuropsychiatric Disorders.

ACS medicinal chemistry letters April 13, 2023 Robert B. Kargbo 4 citations

This patent describes prodrugs—compounds that are metabolically converted into active forms—of DMT, 5-MeO-DMT, and MDMA. When given to a subject, these prodrugs could potentially be used to treat neurological diseases. The disclosure outlines methods for potentially treating conditions including major depressive disorder, post-traumatic stress disorder, Alzheimer's disease, Parkinson's disease, schizophrenia, frontotemporal dementia, Parkinson's dementia, dementia, Lewy body dementia, multiple system atrophy, or substance abuse.

Innovative Psychedelic Therapies: Harnessing 5-MeO-DMT and DMT for Mental Health Treatment.

ACS medicinal chemistry letters November 14, 2024 Robert B. Kargbo 3 citations

Recent patents show new ways to use the psychedelic compounds 5-MeO-DMT and DMT to treat mental health disorders like depression, anxiety, and trauma-related conditions. Innovations include combining 5-MeO-DMT with mood preparation agents to improve safety and effectiveness, creating DMT prodrugs for better drug absorption and processing in the body, and designing tailored therapies for specific groups such as breastfeeding mothers. These developments offer potential new options for patients with treatment-resistant mental disorders, reflecting the growing role of psychedelics in mental health care.

Psychoplastogens: A Novel Therapeutic Approach for Neurological Diseases and Disorders.

ACS medicinal chemistry letters September 14, 2023 Robert B. Kargbo 3 citations

Psychoplastogens—substances that stimulate neuronal growth and enhance neural structures—may help counteract changes in synaptic connectivity and plasticity common in neurological diseases. These compounds activate key targets such as AMPA receptors, TrkB, and mTOR. Examples include ketamine, scopolamine, N,N-dimethyltryptamine, and rapastinel. Clinical trials show psychedelic psychoplastogens have antidepressant, anxiolytic, and anti-addictive effects. The patent highlights potential novel therapies for neurological disorders by modulating synaptic connections and plasticity.

Pioneering Changes in Psychiatry: Biomarkers, Psychedelics, and AI.

ACS Med Chem Lett August 18, 2023 Robert B. Kargbo 3 citations

This viewpoint argues that combining biomarkers, psychedelics, and artificial intelligence could improve psychiatric diagnostics, prognosis, and treatment. Psychedelics show promise in therapy, and AI may help predict how individuals will respond to treatments. However, significant challenges remain, including ethical and practical hurdles. The authors call for further research to develop more precise, personalized psychiatric care.

Advancements in Psychoactive Alkaloid Delivery, Neuroenhancement, and Psychedelic Therapies: Exploring the Frontiers of Modern Pharmacology

ACS Medicinal Chemistry Letters May 8, 2024 Robert B. Kargbo 2 citations

Advancements in pharmacology are being made through novel delivery and application of psychoactive substances. Innovations include transdermal formulations for psychoactive alkaloids, neuroenhancement techniques to augment emotional responses, and intravenous infusion of psilocybin or psilocin for therapeutic purposes. The characterization and potential uses of crystalline forms of tryptamine derivatives are also explored. These developments represent progress in drug delivery systems, neurostimulation methods, and the therapeutic use of psychedelic compounds, potentially revolutionizing treatment for psychological and neurological disorders.

Subhallucinogenic Concentrations of Substituted Phenethylamines as a Novel Therapeutic Approach for Inflammatory and Neurological Disorders.

ACS medicinal chemistry letters July 13, 2023 Robert B. Kargbo 2 citations

A patent describes a method for treating inflammatory or neurological disorders by administering a composition containing a subhallucinogenic dose of a substituted phenethylamine, such as those from the 2C-X family (e.g., 2C-H, 2C-I, 2C-B, or 2C-E). The dose depends on the severity of chronic inflammation: 25 mg for mild, 50 mg for moderate, and 100 mg for severe cases. The method is intended for subjects in need of treatment.

Synthesis of Psilocin, Psilocybin and 5‐MeO‐DMT Succinate, All Labelled With Carbon‐14 at the Indole 2‐Position

Journal of Labelled Compounds and Radiopharmaceuticals July 1, 2025 Rodney D. Brown, Niall M. Hamilton, Connor Mallon et al. 1 citation

Three new radiolabelled versions of the psychedelic compounds psilocin, psilocybin, and 5-MeO-DMT were synthesized, each with carbon-14 at the 2-position of the indole ring. The synthesis used a common route: attaching the dimethylaminoethyl side chain to substituted indole intermediates via oxalyl chloride, dimethylamine, and lithium aluminium hydride reduction. Psilocybin-2-14C at 234 μCi/mg showed limited stability, but a 5.5-fold dilution with unlabelled psilocybin maintained >97.5% radiochemical purity after one month at ≤−70°C. 5-MeO-DMT-2-14C succinate at 173 μCi/mg remained 98.0% pure after six months at ≤−70°C, supporting long-term studies. These labelled compounds enable in vivo pharmacokinetic and metabolic studies of psychedelic tryptamines, aiding ADME and mass balance research for potential regulatory approval in treating depression, anxiety, and PTSD.

Optimized Parenteral and Intranasal Formulations of Tryptamine Psychedelics for Rapid-Acting Antidepressant Therapy.

ACS medicinal chemistry letters June 12, 2025 Robert B. Kargbo 1 citation

New formulations of the psychedelic compounds DMT and 5-MeO-DMT allow injection or nasal spray delivery, bypassing the body's rapid breakdown of these drugs. These delivery methods produce fast-acting, short-lived therapeutic effects, making them suitable for controlled psychiatric treatments like depression that does not respond to standard therapies. The formulations aim to improve tolerability, ease of use, and clinical practicality.

Reducing Cardiovascular Side Effects of DMT Using Beta-Blockers.

ACS medicinal chemistry letters May 8, 2025 Robert B. Kargbo 1 citation

DMT produces fast-acting antidepressant effects, but its use is limited by acute side effects like high blood pressure and rapid heart rate. This work describes coformulations of DMT with short-acting beta-blockers or nitrates that are matched to DMT's pharmacokinetics. These combinations reduce peripheral cardiovascular risks without interfering with the central therapeutic effects, potentially enabling safer psychedelic therapy for vulnerable populations.

Expanding the Therapeutic Horizons of Psilocybin in Mental Health

ACS Medicinal Chemistry Letters October 15, 2024 Robert B. Kargbo 1 citation

Psilocybin, a naturally occurring psychedelic compound, shows promise as a therapeutic agent for mental health. Innovations include clinical trials targeting severe psychiatric conditions, incorporating low-dose psilocybin into dietary products for general mental well-being, and personalizing dosing for optimal treatment of depression and anxiety. These developments highlight psilocybin's versatility and potential to transform conventional mental health treatment through personalized medicine and accessible wellness applications.

Innovative Ketamine Formulations: Enhancing Therapeutic Efficacy and Safety.

ACS medicinal chemistry letters August 8, 2024 Robert B. Kargbo 1 citation

Ketamine, originally an anesthetic, is now used for depression and chronic pain but causes side effects like hallucinations and dizziness from rapid blood concentration spikes. Recent patents describe new delivery methods: subcutaneous injections, ketamine conjugates with other molecules, and dual-release formulations combined with aspirin. These innovations aim to improve how the drug is absorbed and processed in the body, potentially enhancing therapeutic outcomes and safety.