EGCG and Curcumin Combo Reverses Cognitive Decline: New Findings

Highlights

• Mouse models for aging exhibit memory impairments, yet the combination of epigallocatechin 3 gallate (EGCG) and curcumin restores youthful cognition.
• The combination of EGCG and curcumin reverses the age-associated decline of neuronal antioxidant enzymes glutathione (GSH) and superoxide dismutase (SOD).
• EGCG and curcumin combined blunt age-associated neuronal stress from highly reactive, oxygen-containing molecules (reactive oxygen species [ROS]).

A primary driver of neuronal aging is oxidative stress — cellular damage caused by the buildup of highly reactive byproducts of physiological reactions (ROS). To counter oxidative stress, the body possesses native antioxidants like GSH and SOD, however, their concentrations and thus, their capabilities to offset ROS, decline with age. Therefore, plant-derived antioxidants like ECGC found in green tea and curcumin from turmeric have been proposed to counter ROSs’ contribution to cognitive decline during aging. Yet their capabilities to reverse age-related cognitive decline when combined hadn’t been explored until a recent study published in Scientific Reports.

In the study, Reza and colleagues from North South University in Bangladesh show that treating mouse models for aging with a combination of EGCG and curcumin restores their memory-forming capacities to that of youthful mice. The EGCG and curcumin combination likely works against cognitive aging by restoring antioxidant enzyme concentrations of GSH and SOD to youthful levels. Moreover, EGCG and curcumin together lower levels of molecular markers for oxidative stress — nitrous oxide (NO) and malondialdehyde (MDA) — confirming their benefits as antioxidant boosters. These findings show that EGCG and curcumin combined restore cognition and memory in aged mice better than treatment with either molecule alone by improving natural antioxidant levels and thwarting oxidative stress.

“Our present study concludes that the combined EGCG and curcumin substantiate the powerful protection via producing potential pharmacological actions in brain aging,” said Reza and colleagues.

EGCG and Curcumin Restore Memory to a Youthful State and Suppress Oxidative Stress

To determine whether EGCG and curcumin together enhance cognition better than either molecule supplemented on its own, Reza and colleagues used a passive avoidance test. In this test, mice had to choose whether to localize to a lit chamber or a dark chamber. Mice typically prefer the dark chamber, but the catch was that they experienced an electrical foot shock in the dark chamber. The amount of time they spent in the lit chamber thus represented their memory of the foot shock that went along with entering the dark chamber.

Moreover, Reza and colleagues utilized two mouse models for aging, mice exposed to an oxidative stress-inducing molecule called D-galactose that rapidly induces brain aging, and naturally aged mice. Interestingly, both mouse models for aging spent less time in the lit chamber (retention time) compared to young mice. For the D-galactose aged mouse model, neither EGCG nor curcumin supplementation alone significantly improved this retention time. However, the EGCG plus curcumin combination did, leading to retention times similar to astaxanthin, a potent antioxidant found in seafood and some algae.

In contrast, the naturally aged mouse model showed improved retention times with EGCG alone and with the EGCG plus curcumin combination, with the EGCG plus curcumin retention time surpassing EGCG alone. The EGCG plus curcumin treatment again showed benefits to memory similar to astaxanthin for the naturally aged mouse model. These findings show that cognitive benefits from the combination of EGCG and curcumin surpass those of either molecule on its own and that they are comparable to the effective antioxidant astaxanthin.

Reza and colleagues sought to find whether the benefits of EGCG and curcumin for cognition and memory stem from their abilities to increase cell native antioxidants GSH and SOD. They measured the effects of EGCG and curcumin on their own and together and again compared them to the effective antioxidant astaxanthin. The combination of EGCG and curcumin drove significantly higher GSH and SOD concentrations in the two brain aging models compared to either molecule on its own. These data show that the EGCG and curcumin combination restores native antioxidants GSH and SOD to youthful concentrations, similar to astaxanthin, providing insight into its actions against oxidative stress.

Since increasing levels of the natural antioxidants GSH and SOD should theoretically diminish oxidative stress arising from ROS, Reza and colleagues measured the combination’s effects on markers of oxidative stress. The researchers found for both mouse models of aging that the EGCG and curcumin combination provided superior antioxidant benefits against oxidative stress markers NO and MDA than either molecule on its own. The benefits of EGCG and curcumin combined against ROS markers NO and MDA were also similar to astaxanthin. These results show that the EGCG and curcumin combination confers benefits against ROS that surpass those from either molecule on its own.

“We investigated the beneficial effects of EGCG and curcumin on oxidative stress in the two robust aging mice models by performing behavioral and biochemical studies,” said Reza and colleagues. “A combination of EGCG with curcumin exhibits greater protection from aging-related memory impairment by modulating oxidative stress biomarkers.”

Potential Synergistic Benefits from Combining Nutraceuticals

The study shows that the combination of EGCG and curcumin has a greater beneficial effect on cognition than either molecule alone. Combining these antioxidant supplements increases neuronal concentrations of native antioxidants GSH and SOD, diminishing oxidative stress.

Interestingly, the other antioxidant Reza and colleagues compared EGCG and curcumin to, astaxanthin, has already been shown to improve memory dysfunction in rodents. This effective antioxidant has also been shown to alleviate memory impairments and brain protein aggregations in a mouse model for Alzheimer’s disease. Along those lines, it would be interesting to find whether combining astaxanthin with EGCG and curcumin provides further cognition enhancement during aging.

EGCG, curcumin, and astaxanthin are all available as supplements. EGCG, a green tea component, can be purchased for $15 to $20 for a month’s supply in supplement capsule form. Curcumin, an orange substance found in turmeric, can be purchased for between $13 and $20 for a month’s supply of supplement tablets. Moreover, astaxanthin, a substance with a pink hue found in many seafoods including shrimp and lobster, can be purchased as a supplement for $10 to $25 for a month’s supply of capsules.