Curcumin and Dementia: A Systematic Review of Its Effects on Oxidative Stress and Cognitive Outcomes in Animal Models

Abstract

Dementia is marked by progressive cognitive decline linked to oxidative stress, neuroinflammation, and synaptic dysfunction. Curcumin, a natural compound from Curcuma longa, has shown promising neuroprotective effects. This systematic review analyzed 29 preclinical studies using rodent models of dementia induced by chemical, genetic, or dietary methods. The review focused on curcumin's effects on oxidative stress, inflammation, and cognitive outcomes. All studies assessing malondialdehyde (MDA) reported significant reductions, indicating reduced oxidative stress. Superoxide dismutase (SOD) activity increased in all measured cases, while glutathione (GSH) levels rose in about one-third of studies. A literature search was comprehensively conducted using PubMed, Scopus, AMED, and LILACS databases through April 2024. Curcumin also demonstrated anti-inflammatory properties, with over 80% of studies showing reduced levels of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β. Additionally, 40% of studies noted increases in anti-inflammatory markers like IL-4 and IGF-1. Cognitive performance improved in around 80% of studies, especially in spatial learning and memory. Some studies also reported behavioral improvements, including reduced anxiety and enhanced locomotion. Curcumin demonstrated potent antioxidative, anti-inflammatory, and cognitive-enhancing effects across diverse dementia models. Its ability to modulate multiple pathological pathways highlights its potential as a bioactive compound for mitigating cognitive decline associated with neurodegenerative diseases. However, variability in study design and curcumin formulations suggests the need for standardized protocols and further high-quality research to facilitate clinical translation.

Keywords: animal models; antioxidant; cognitive function; curcuma longa; curcumin; dementia; neuroinflammation; oxidative stress.

Figure 1

PRISMA flow diagram of study selection.

Figure 2

Quality of reporting and bias evaluation conducted with SYRCLE’s risk of bias tool (Risk-of-bias VISualization (robvis) [57]) illustrating the quality of reporting and bias risk in the included studies [28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56].

Figure 3

Quality of reporting and bias evaluation conducted with SYRCLE’s risk of bias tool evaluating biases related to selection, performance, detection, attrition, and other factors [57].

Figure 4

Geographical distribution ((A)—upper panel) and publication year ((B)—lower panel) of included studies.

Figure 5

Types of rodents (A), gender of rodents (B), age of rodents (C,D), and weight distribution of the rodents (E,F) used in the included studies reflect the demographics of rodents assessed for the effects of curcumin in research on dementia.

Figure 6

The detailed methods for inducing dementia in these rodents (A,B) are included in the studies.

Figure 7

Treatment duration of curcumin/Curcuma in the rodents.

Figure 8

Beneficial effects of curcumin on cognitive functions, inflammatory markers, and oxidative stress.