摘要
Copper is a vital trace element in biological systems. However, toxic levels can precipitate neurodegenerative diseases like Alzheimer’s disease which occurs with advancement in age. Chlorogenic acid (CGA) is a phytonutrient widely distributed in the diet. This study serves as a preliminary investigation to studying the preventive or ameliorative role of CGA in the light of Alzheimer’s disease with copper toxicity being the model in Drosophila melanogaster.
- melanogaster (Oregon strain) were allotted into four (4) groups of five vials with 50 flies each and exposed to copper sulphate 0, 0.25, 0.5 and 1.0 mM, respectively) for 7 days for survival assay, biochemical indices (H2O2, non-protein thiols, total thiol and nitric oxide (NO), and behavioural activities (negative geotaxis and eclosion rate). For the study with CGA, the flies were allotted to six (6) groups of five vials with 50 flies each and treated as follows: 0- control (distilled water), 2% ethanol (vehicle), 15, 30, 45, and 60 mg/kg diet of CGA, respectively for 28 days for the longevity assay. Biochemical (H2O2, non-protein thiols, total thiol and nitric oxide (NO) and behavioural (negative geotaxis and eclosion rate) assays were performed in flies treated with CGA for 7 days using similar groups comprising of 2% ethanol (control), and CGA at 15, 30, and 45 mg/kg diet.
Copper reduced the survival of the flies, especially at 1mM, and the non-protein thiol and total thiol levels were significantly (p < 0.05) reduced while negative geotaxis and eclosion rate were unaffected. At 15, 30, and 45 mg/kg diet of CGA, the longevity of the flies was improved. The concentrations of hydrogen peroxide and nitric oxide were significantly (p < 0.05) douced in a dose-dependent manner, and levels of total thiol and non-protein thiols increased in a dose-dependent fashion with it being significant at 45 mg/kg diet of CGA. CGA did not affect the negative geotaxis and the eclosion rate of the flies.
Copper demonstrated toxicity at the concentrations tested, and chlorogenic acid gives the presentation that it is a potential antioxidant agent.