The protective role of plant biophenols in mechanisms of Alzheimer's disease  Syed H. Omar, Christopher J. Scott, Adam S. Hamlin, Hassan K. Obied  Journal of Nutritional Biochemistry  Volume 47, Pages 1-20 (September 2017) DOI: 10.1016/j.jnutbio.2017.02.016 Copyright © 2017 Elsevier Inc. Terms and Conditions

Fig. 1 Schematic diagram illustrating AD pathology and the potential role of biophenols. (a) In amyloidogenic pathway, enzymatic action (β-secretase) producing extracellular Aβ peptide and ultimately leads to AD. Biophenols covalently bond to Aβ and inhibit their further aggregation. (b) Soluble tau attached with the microtubules and supports axonal transport, became hyperphosphorylated in AD, caused detachment of tau from microtubules and led to formation of neurofibrillary tangles and, ultimately, neuronal death followed by cognition impairment. Biophenols inhibited the tau fibrillization or aggregation along with inhibition of unfolding of tau from microtubule and ceases further tangle formation. (c) Increase in production of free radicals leading to disrupt the equilibrium between production and clearance of RONS, causing neuronal hypoxia and degeneration and, ultimately, involved in the pathogenesis of AD. Biophenols reduces the RONS production and oxidative stress. (d) Altered mitochondrial enzyme release causes defect in ETC, leading to produce increased RONS and altered calcium homeostasis. Biophenols inhibited the increase in RONS production which ultimately leads to decrease in production of Aβ. Journal of Nutritional Biochemistry 2017 47, 1-20DOI: (10.1016/j.jnutbio.2017.02.016) Copyright © 2017 Elsevier Inc. Terms and Conditions

Fig. 2 Chemical structures of important biophenols with anti-AD activities. Journal of Nutritional Biochemistry 2017 47, 1-20DOI: (10.1016/j.jnutbio.2017.02.016) Copyright © 2017 Elsevier Inc. Terms and Conditions

Fig. 3 A holistic approach is required to evaluate the anti-AD properties of phytochemicals where activity is examined at cellular, tissue and functional levels. Journal of Nutritional Biochemistry 2017 47, 1-20DOI: (10.1016/j.jnutbio.2017.02.016) Copyright © 2017 Elsevier Inc. Terms and Conditions

Journal of Nutritional Biochemistry 2017 47, 1-20DOI: (10. 1016/j Journal of Nutritional Biochemistry 2017 47, 1-20DOI: (10.1016/j.jnutbio.2017.02.016) Copyright © 2017 Elsevier Inc. Terms and Conditions