ASCERTAINING THE ANTIOXIDANT PROPERTIES OF QUERCETIN AGAINST OXIDATIVE STRESS IN COMBATING ALZHEIMER’S DISEASE: A REVIEW

Quercetin is a flavonoid compound mostly found in plants including fruits, vegetables, green tea, red wine etc. Apart from having many health effects, quercetin possesses antioxidant capacities. It can scavenge hydroxyl radical (OH-), hydrogen peroxide (H2O2), nitric oxide (NO) and other free radicals. The reactive oxygen species have high potential to interrupt the functions of lipids, proteins, DNA and RNA which can lead to various epigenetic changes. These components in the neurons are more vulnerable to oxidative stress. Mitochondrial dysfunctions, amyloidopathy, taopathy, metal accumulation, synaptic dysfunctions, genetic and neuro- inflammation can cause oxidative stress in a cell, which is responsible for development of Alzheimer’s disease (AD). The relationship between oxidative stress and AD suggests that oxidative stress is an important contributor of the pathological process for AD and antioxidants may be useful for the treatment. It is proposed that quercetin would be the best choice to act against oxidative stress and hence to AD as it has antioxidant properties as well can inhibit the crowding of macromolecules such as Aβ, Tau protein etc. The neuroprotective effects of quercetin are regulated through nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Paraoxonase-2, c-Jun- N-terminal kinase (JNK), Protein kinase C, Mitogen-activated protein kinase (MAPK) and PI3K/AKt pathways. Therefore the aim of this review is to study the antioxidant effects of quercetin against oxidative stress and hence to prevent the pathogenesis of AD.