RESUMO
BACKGROUND: Phytocannabinoids (pCBs) have been shown to inhibit the aggregation and neurotoxicity of the neurotoxic Alzheimer's disease protein beta amyloid (Aß). We characterized the capacity of six pCBs-cannabichromene (CBC), cannabigerol (CBG), cannabinol (CBN), cannabidivarin (CBDV), cannabidiol (CBD) and Δ9 -tetrahydrocannabinol (Δ9 -THC)-to disrupt Aß aggregation and protect against Aß-evoked neurotoxicity in PC12 cells. METHODS: Neuroprotection against lipid peroxidation and Aß-induced cytotoxicity was assessed using the MTT assay. Transmission electron microscopy was used to visualize pCB effects on Aß aggregation and fluorescence microscopy, with morphometrics and principal component analysis to assess PC12 cell morphology. RESULTS: CBD inhibited lipid peroxidation with no significant effect on Aß toxicity, whilst CBN, CBDV and CBG provided neuroprotection. CBC, CBG and CBN inhibited Aß1-42 -induced neurotoxicity in PC12 cells, as did Δ9 -THC, CBD and CBDV. CBC, CBN and CBDV inhibited Aß aggregation, whilst Δ9 -THC reduced aggregate density. Aß1-42 induced morphological changes in PC12 cells, including a reduction in neuritic projections and rounded cell morphology. CBC and CBG inhibited this effect, whilst Δ9 -THC, CBD and CBDV did not alter Aß1-42 effects on cell morphology. CONCLUSIONS: These findings highlight the neuroprotective activity of CBC, CBG and CBN as novel pCBs associated with variable effects on Aß-evoked neurite damage and inhibition of amyloid ß aggregation.