ABSTRACT
Neurodegenerative disorders have been reported to be related to aging, inammation, and oxidative stress. These risk factors contribute to the degeneration of neural cells, leading to neuronal dysfunction and disorders. Neural cells in aging brains are more vulnerable to oxidative stress because of their high metabolic activity and low antioxidant defense capacity (Aruoma 2002; Floyd et al. 2001; Halliwell 1992). Functional deterioration of neural cells and neurotoxic substances cause the vicious
8.1 Introduction .................................................................................................. 275 8.2 Dietary and Citrus Flavonoids ...................................................................... 276 8.3 Antioxidant Properties of Dietary and Citrus Flavonoids ............................ 277 8.4 Flavonoids: Antioxidants or Signaling Molecules? ...................................... 277 8.5 Benecial Bioactivities of Flavonoids on Neurological Processes
via Signaling Regulations ............................................................................. 278 8.6 Neuroprotection via Citrus Flavonoids and Effects on Memory
and Cognition................................................................................................280 8.7 Anti-Inammatory Actions of Citrus Flavonoids Conferring
Neuroprotective Effects ................................................................................ 281 8.8 Molecular Mechanisms Underlying the Neuroprotection of Dietary
and Citrus Flavonoids ................................................................................... 282 8.8.1 Demand for Flavonoids as Pharmacological
and Neuroprotective Agents ............................................................. 282 8.8.2 Neuroprotective Signaling Pathways of Flavonoids ......................... 283 8.8.3 Mechanisms Underlying the Neuroprotection of Citrus Flavonoids .... 283
8.9 Applications of Citrus Flavonoids to Other Neurodegenerative Disorders ....285 8.10 Applied Issues of Citrus Flavonoids as Neuroprotective Agents .................286 8.11 Conclusions ................................................................................................... 289 Acknowledgment ................................................................................................... 289 References .............................................................................................................. 289
cycles of oxidative stress, inammation, and disruption of calcium homeostasis during brain aging, which can result in neurotoxicity, memory and cognition declines, and neurodegenerative diseases (Annunziato et al. 2002; Buttereld et al. 1999; Yuan and Yankner 2000). Additionally, hydrogen peroxide is produced in β-amyloid (Aβ) aggregation, dopamine oxidation, and brain ischemia/reperfusion, leading to protein and lipid oxidation and DNA damage in neurons (Mattson 2004; Oikawa et al. 2006; Warner et al. 2004).
