Silymarin attenuates aspartame-induced variation in mouse behaviour, cerebrocortical morphology and oxidative stress markers.

Objective: We assessed the impacts of silymarin co-administration on aspartame-induced changes in novelty-induced behaviours, memory, anxiety-related behaviours, cerebral antioxidant status and histomorphology in mice.

Method: Six groups of mice were administered vehicle (distilled water), silymarin (25mg/kg), aspartame (at 160 or 320mg/kg), and silymarin (25mg/kg) co-administered with aspartame at 160 or 320mg/kg daily for 21days, via an oral cannula. Behaviours were assessed after the first and last dose of treatment. Animals were sacrificed thereafter. Brain homogenates were used to assess antioxidant status; while sections of the cerebral cortex were processed for routine histology.

Result: Repeated co-administration of silymarin with aspartame resulted in significant suppression of horizontal locomotion and rearing, while grooming behaviour was enhanced; when compared to aspartame alone. Spatial working-memory showed significant improvement only after acute co-administration, while anxiety-related behaviours were reduced after repeated administration of both silymarin and aspartame. Cerebral cortical morphological integrity was better preserved, and astrocytic reactivity reduced with silymarin co-administration. Brain activity of superoxide dismutase and nitric oxide levels were decreased, while glutathione peroxidase activity was increased, when compared to levels seen with aspartame alone.

Conclusion: The study shows that co-administration of silymarin with aspartame was associated with significant attenuation of central effects, when compared to administration of aspartame alone.