Effect of Watermelon Extract on Nerve Conduction Velocity, Memory, and T4 Level in Rats

Background: Watermelon is a fruit with the thirst-quenching effect and especially is consumed in summer. In this study, the effect of consumption of watermelon extract (in drinking water) on thyroid hormone level (TT4), animals' weight, water and food consumption, nerve conduction velocity (NCV), and memory in Wistar rats were investigated. Materials and Methods: Twenty-four male Wistar rats were divided into three groups: control, CT 1500 mg/kg, and CT 3000 mg/kg (n = 8, in each group). Watermelon extract was administered for 42 days. The results measured in this study were analyzed with repeated measures or one-way analysis of variance and compared by the least significant difference post hoc. P < 0.05 was considered as significant difference. Results: The results showed that animals' weight in both the treatment groups decreased compared to the control group (P < 0.05 and P < 0.01, respectively). Water and food consumption and the level of TT4 increased when compared to the control group in both the treated groups (both P < 0.001). NCV in both the treated groups decreased in comparison with the control group (both P < 0.001). Spatial memory did not change significantly, but passive avoidance memory in both the treated groups significantly decreased in comparison to the control group (respectively, with P < 0.05 and P < 0.01). Conclusion: Based on these finding, in spite of increase in food and water consumption in the treated groups, animal weight did not increase significantly. Impairment in memory and decrease in NCV were also occurred, but TT4 level was increased in animals treated with watermelon extract.