mimulone and diplacone

Flavonoids form a diverse class of naturally occurring polyphenols ascribed various biological activities, including inhibition of amyloid β (Aβ) fibrillisation and neurotoxicity of relevance to Alzheimer's disease. Cannabis contains a unique subset of prenylated flavonoids, the cannflavins. While selected conventional flavonoids have demonstrated anti-amyloid and neuroprotective potential, any neuroprotective bioactivity of prenylated flavonoids has not been determined. We evaluated the in vitro neuroprotective and anti-aggregative properties of the novel geranylated cannabis-derived flavonoid, cannflavin A against Aβ. Neuronal viability were assessed in PC12 cells biochemically using the MTT assay in the presence of each flavonoid (1-200 µM) for 48 h. Sub-toxic threshold test concentrations of each flavonoid were then applied to cells, alone or with concomitant incubation with the lipid peroxidant tert-butyl hyrdroperoxide (t-bhp) or amyloid β (Aβ. Cannflavin A demonstrated intrinsic hormetic effects on cell viability, increasing viability by 40% from 1 to 10 µM but displaying neurotoxicity at higher (>10-100 µM) concentrations. Neither mimulone nor diplacone exhibited such a biphasic effect, instead showing only concentration-dependent neurotoxicity, with diplacone the more potent (from >1 µM). However at the lower concentrations (<10 µM), cannflavin A increased cell viability by up to 40%, while 10 µM cannflavin A inhibited the neurotoxicity elicited by Aβ. These findings highlight a concentration-dependent hormetic and neuroprotective role of cannflavin A against Aβ-mediated neurotoxicity, associated with an inhibition of Aβ fibrillisation. The efficacy of the cannabis flavone may itself direct further lead development targeting neurodegeneration in Alzheimer's disease. However, the geranylated flavonoids generally displayed a comparatively potent neurotoxicity not observed with many conventional flavonoids in vitro.

Topics: Amyloid beta-Peptides; Animals; Benzothiazoles; Cell Survival; Dose-Response Relationship, Drug; Flavanones; Flavones; Fluorescence; Hormesis; Microscopy, Electron, Transmission; Models, Molecular; Neuroprotective Agents; Neurotoxicity Syndromes; PC12 Cells; Rats

Diplacone (1) and mimulone (2), two geranylated flavanones, have previously shown anti-inflammatory and antiradical activity in vitro. The present study aimed to evaluate their activity in vivo on a model of colitis induced in Wistar rats by an oral administration of dextran sulfate sodium (DSS). Diplacone (1) and mimulone (2) were administered at a bolus dose of 25mg/kg by gastric gavage 48 and 24h prior to the induction of colitis by DSS and every 24h on the following days of the experiment. The effect of the treatment was assessed by monitoring the disease activity index (DAI), histopathological examination, evaluation of the weight and length of the colon and by analysis of the levels and activities of cyclooxygenase-2 (COX-2), matrix metalloproteinase-2 (MMP2), superoxide dismutase-2 (SOD2), and catalase (CAT) in the inflamed tissue. Administration of the test compounds prior and after induction of colitis ameliorated the symptoms of colitis (diarrhea, presence of the blood in the stool) and delayed their onset. The ability of compounds 1 and 2 to reduce the levels of COX-2 and to increase the ratio of pro-MMP2/MMP2 activity correlates with the values of the DAI. The lowering of the levels of the antioxidant enzymes SOD2 and CAT reflects the ability of the test compounds to scavenge reactive oxygen species.

Topics: Animals; Catalase; Colitis; Colon; Cyclooxygenase 2; Dextran Sulfate; Disease Models, Animal; Flavanones; Male; Matrix Metalloproteinase 2; Molecular Structure; Rats, Wistar; Superoxide Dismutase