Impact of different formulations of pharmaceutical cannabis-based extracts on the neuroprotective effect in cerebellar granule cell cultures

Abstract

Preclinical research supports the benefits of pharmaceutical cannabis-based extracts for treating different medical conditions (e. g., epilepsy); however, their neuroprotective potential has not been widely investigated. In addition, there is still controversy about the impact of other factors in the beneficial effect of these extracts (e.g., the entourage effect, and oil formulations). We evaluated the neuroprotective activity of Epifractan (EPI), a cannabis-based medicinal extract containing a high level of cannabidiol (CBD), components like terpenoids and flavonoids, and trace levels of Δ9-tetrahydrocannabinol and the acid form of CBD. Using primary cultures of cerebellar granule cells, we determined the ability of EPI to counteract the rotenone-induced neurotoxicity by analyzing cell viability and morphology of neurons and astrocytes by immunocytochemical assays. The effect of EPI was compared with XALEX, a plant-derived and highly purified CBD formulation (XAL), and pure CBD crystals (CBD). The results revealed that EPI induced a significant reduction in the rotenone-induced neurotoxicity in a wide range of concentrations without causing neurotoxicity per se. EPI showed a similar effect to XAL suggesting that no additive or synergistic interactions (i.e., entourage effect) between individual substances present in EPI occurred. In contrast, CBD crystals did show a different profile to EPI and XAL since a neurotoxic effect per se was observed at the higher concentrations assayed. Medium-chain triglyceride oil used in EPI formulation could explain this difference. Our data support a neuroprotective effect of EPI which may provide neuroprotection in different neurodegenerative processes. The results highlight the role of CBD as the active component of EPI but also support the need for an appropriate formulation to dilute pharmaceutical cannabis-based product