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Study breakdown

CBD Inhibited a Brain Enzyme Linked to Neurodegeneration at Nanomolar Concentrations in Lab Tests

Lab StudyPreliminary evidence
The takeaway

Virtual screening and lab experiments identified CBD as a selective inhibitor of phosphodiesterase 9 (PDE9), an enzyme implicated in neurodegeneration, with nanomolar-range potency confirmed in vitro.

Neuroscience researchers, pharmacologists, drug development scientists studying neurodegeneration.

CBD inhibited brain enzyme PDE9 at nanomolar concentrations in vitro

What the researchers found

Computational screening of 7 phytocannabinoids and 4 terpenes identified CBD as a potential PDE9 ligand with a calculated binding energy of -9.1 kcal/mol and stable molecular dynamics interaction. In vitro PDE9 inhibition assay confirmed CBD inhibits the enzyme in the nanomolar range.

Why it matters

PDE9 inhibitors are being studied as potential treatments for Alzheimer disease and other neurodegenerative conditions. If CBD acts partly through PDE9 inhibition, this could explain some of its reported neuroprotective effects and open a new avenue for drug development.

The numbers in context

Binding energy: -9.1 kcal/mol. CBD inhibited PDE9 in the nanomolar range in vitro. 7 phytocannabinoids and 4 terpenes screened.

How the study worked

Combined ligand-based and structure-based virtual screening (docking and molecular dynamics simulations) followed by in vitro PDE9 enzymatic inhibition assay. Screened 7 phytocannabinoids and 4 terpenes.

What this study cannot tell us

In vitro enzymatic assay does not confirm in vivo relevance. Nanomolar potency in a cell-free system may not translate to effective brain concentrations. CBD has many proposed molecular targets, and PDE9 may be one of many. No animal or human data yet.

How to read the evidence

Computational screening validated by in vitro enzymatic assay. Preliminary evidence requiring in vivo confirmation.

When this study was published

Published in 2023.

The bigger picture

CBD has shown neuroprotective effects in various studies, but the mechanisms remain unclear. Identifying PDE9 as a specific molecular target adds a concrete mechanism to what has been a vague body of evidence about CBD and brain health.

Questions still open

  • Does CBD reach brain concentrations sufficient for PDE9 inhibition at typical doses?
  • Would CBD-based PDE9 inhibition show benefits in animal models of neurodegeneration?

Common questions

How might CBD protect the brain?
This study found CBD inhibits PDE9, an enzyme linked to neurodegeneration, at very low concentrations. PDE9 inhibitors are being developed as potential Alzheimer treatments.
Is this evidence that CBD treats Alzheimer disease?
No. This is a lab finding showing CBD can inhibit a relevant enzyme. Whether this translates to neuroprotective effects in humans requires extensive further research.

Read the original research

Virtual screening and in vitro experiments highlight cannabidiol as a drug-like phosphodiesterase 9 inhibitor.

The European journal of neuroscience, 57(12), 1954-1965

Citation

Ribaudo, Giovanni; Landucci, Elisa; Giannangeli, Matteo; Mazzantini, Costanza; Maccarinelli, Giuseppina; Mastinu, Andrea; Bonini, Sara Anna; Memo, Maurizio; Pellegrini-Giampietro, Domenico E; Gianoncelli, Alessandra. (2023). Virtual screening and in vitro experiments highlight cannabidiol as a drug-like phosphodiesterase 9 inhibitor.. The European journal of neuroscience, 57(12), 1954-1965. https://doi.org/10.1111/ejn.15869

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