Effects of Sub-acute Administration of Onion Waste Quercetin on the Hippocampus of Mice: A Histological Approach

Quercetin is a flavonoid with a great capability of crossing the blood-brain barrier. It is reported to exert numerous beneficial effects on both animal and human health. The study evaluates the effects of onion waste quercetin (OWQ) on the histology of the hippocampus and dentate gyrus of mice. Twenty mice were assigned into four groups (n=5). The groups were given distilled water, and OWQ at 95mg/kg, 190mg/kg, and 380mg/kg respectively for 28 days. The brain of each mouse was harvested afterward, weighed, and processed for light microscopy. The normal and degenerating cells in the dentate gyrus and hippocampus Cornu Ammonis (CA1 & CA3) were counted. The micrographs of the dentate gyrus showed normal molecular, granular, and polymorphic layers in the control mice, as well as the mice, treated with OWQ with few degenerating cells in the granular layer of OWQ-treated (190mg/kg) mice. The CA3 area of the hippocampus showed normal molecular and polymorphic layers in OWQ-treated mice. However, the granular layer of the mice that received OWQ at 190mg/kg showed numerous degenerating cells. OWQ especially at 95mg/kg was found to significantly increase the number of normal cells in the dentate gyrus and hippocampus (CA1 & CA3) of the brain compared to the control at P< .05. It also significantly decreased degenerating cells compared to the control (P< .05). In conclusion, onion waste quercetin, especially at 95mg/kg was found to maintain the pool of normal cells within the dentate gyrus and hippocampus of mice brain.