Potential neuroprotective effects of blueberry and lingonberry fruits and leaves

• Main Author: Kalidindi, Swetha
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2014
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/6444/; https://research.library.mun.ca/6444/1/Kalidindi_Swetha_052014_MSc.pdf; https://research.library.mun.ca/6444/3/Kalidindi_Swetha_052014_MSc.pdf

Production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are natural processes occurring in the brain. However, overproduction of ROS and RNS may occur during aging and contribute to neurodegenerative diseases and disorders such as stroke. Phenolic compounds constitute a large class of phytochemicals that are widespread in the plant kingdom and known to have antioxidant capacities. This study aimed to determine the radical scavenging capacity and reducing power, as well as the polyphenolic content in fruits and leaves of blueberries and lingonberries growing in Newfoundland. We determined the potential neuroprotective effect of extracts against glutamate-mediated excitotoxicity, which is believed to contribute to disorders such as stroke and neurodegenerative diseases. We found that extracts of fruits and leaves of blueberry and lingonberry plants have high levels of total soluble phenolics, anthocyanins, tannins, and flavonoids. Overall, the levels of these compounds were significantly higher in the leaves of these plants versus the fruits. Total antioxidant capacity, in terms of radical scavenging activity and reducing power, were much higher in the leaves of both plants as compared to their fruits. We then tested the effects of the extracts against glutamate-mediated excitotoxicity, a pathological process partially involving overproduction of ROS and RNS. Brain-derived cortical cell cultures from neonatal rat pups were prepared and grown for 9-16 days in vitro. Cells were exposed to glutamate (100 μM) for 24 hours. Glutamate-exposed cells displayed morphological alterations such as disrupted cell bodies, and increased dark punctae, which is often indicative of condensed nuclei and delayed cell death. Glutamate caused a ~23% cell loss after 24 hours as determined by the amount of DAPI-positive nuclei. A specific NMDA receptor blocker (AP5) was used to determine the contribution of this receptor type to cell damage. While lingonberry fruit extract did not provide protection from glutamate ...