Several cannabis extracts reduced seizure-like activity in zebrafish as effectively as pure CBD, even though they contained much less CBD, suggesting an entourage effect.
Epilepsy researchers and cannabis scientists studying the entourage effect.
Cannabis extracts matched pure CBD for seizure control despite containing much lower CBD levels
What the researchers found
In a PTZ-induced zebrafish seizure model, 5.7 ug/mL of pure CBD and 10 ug/mL of various cannabis extracts both significantly reduced hyperactivity compared to both PTZ alone and the standard anti-epileptic drug valproic acid. Effective extracts achieved similar results to pure CBD despite containing much lower CBD concentrations, supporting a possible entourage effect.
Why it matters
If whole cannabis extracts can match or exceed pure CBD for seizure control at lower doses, this could make treatment more accessible and potentially reduce side effects associated with high CBD doses.
The numbers in context
5.7 ug/mL pure CBD and 10 ug/mL extracts both significantly reduced movement. Effective extracts contained much lower CBD levels than the pure CBD comparison. Three strains tested with three extraction methods each.
How the study worked
Pentylenetetrazole (PTZ)-induced hyperactivity model in zebrafish larvae. Three cannabis strains tested with three different extraction methods each. Results benchmarked against pure CBD and valproic acid (VPA).
What this study cannot tell us
Zebrafish model is a basic screening tool with limited translation to mammalian or human epilepsy. PTZ-induced hyperactivity is not identical to seizures. Extract composition varies with strain and extraction method. Cannot identify which non-CBD compounds contribute to efficacy.
How to read the evidence
Zebrafish screening model provides preliminary evidence only. Results need validation in mammalian models and clinical trials.
When this study was published
2025 publication.
The bigger picture
This adds to the preclinical evidence for an entourage effect in epilepsy treatment, complementing clinical observations that some patients respond better to full-spectrum cannabis products than CBD isolate.
Questions still open
- Which specific minor cannabinoids or terpenes contribute to the enhanced anti-seizure effects?
- Would clinical trials comparing extracts to pure CBD show the same pattern?
Read the original research
The Anticonvulsant Effects of Different Cannabis Extracts in a Zebrafish Model of Epilepsy.
Biomolecules, 15(5)
Citation
Jackson, Karen; Shabat-Simon, Maytal; Bar-On, Jonathan; Steckler, Rafi; Khatib, Soliman; Tamir, Snait; Pitashny, Paula Adriana. (2025). The Anticonvulsant Effects of Different Cannabis Extracts in a Zebrafish Model of Epilepsy.. Biomolecules, 15(5). https://doi.org/10.3390/biom15050654
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