Use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease

Abstract

This review summarizes and describes the use of curcumin in diagnosis, prevention, and treatment of Alzheimer's disease. For diagnosis of Alzheimer's disease, amyloid-β and highly phosphorylated tau protein are the major biomarkers. Curcumin was developed as an early diagnostic probe based on its natural fluorescence and high binding affinity to amyloid-β. Because of its multi-target effects, curcumin has protective and preventive effects on many chronic diseases such as cerebrovascular disease, hypertension, and hyperlipidemia. For prevention and treatment of Alzheimer's disease, curcumin has been shown to effectively maintain the normal structure and function of cerebral vessels, mitochondria, and synapses, reduce risk factors for a variety of chronic diseases, and decrease the risk of Alzheimer's disease. The effect of curcumin on Alzheimer's disease involves multiple signaling pathways: anti-amyloid and metal iron chelating properties, antioxidation and anti-inflammatory activities. Indeed, there is a scientific basis for the rational application of curcumin in prevention and treatment of Alzheimer's disease.

Keywords: Alzheimer's disease; biological availability; chemical components; curcumin; early diagnosis; magnetic resonance imaging; nerve regeneration; neural regeneration; neurodegeneration; positron emission tomography; senile dementia.

Figure 1

Curcumin is a sensitive fluorochrome for AD diagnosis. (A) Curcumin derivatives for PET imaging. [¹⁸F] fluoropropyl-substituted curcumin, Ki = 0.07 nM to Aβ (Ryu et al., 2006); ¹⁸F-curcumin derivative (Rokka et al., 2014). (B) Curcumin analogue CRANAD-28 for two-photon microscopy imaging (Zhang et al., 2014). Aβ₄₀ monomers: Kd = 68.80 nM, Aβ₄₂ monomers: Kd = 159.70 nM, Aβ₄₂ dimers: Kd = 162.90 nM, Aβ₄₂ oligomers: Kd = 85.70 nM, Aβ₄₀ aggregates: Kd = 52.40 nM. (C) Curcumin analogue FMeC1 for magnetic resonance imaging (Yanagisawa et al., 2011). (D) Curcumin analogues for near-infrared fluorescence imaging. CRANAD-1, Kd =38.00 nM; CRANAD-58, Aβ₄₀: Kd = 105.80 nM, Aβ₄₂: Kd = 45.80 nM; CRANAD-3, Aβ₄₀ monomers: Kd = 24.00 nM, Aβ₄₂ monomers: Kd = 23.00 nM (Ran et al., 2009; Zhang et al., 2013, 2015). AD: Alzheimer's disease; Aβ: amyloid-β; PET: positron emission tomography.

Figure 2

Curcumin: a pleiotropic agent for treatment of Alzheimer's disease. Curcumin decreases Aβ production, inhibits Aβ aggregation, and promotes Aβ clearance. Besides, curcumin inhibits inflammatory signal pathways and decreases the production of inflammatory cytokines. Additionally, curcumin reduces oxidative stress and scavenge radicals. Aβ: Amyloid β-protein.