Neuroprotection induced by catechins in aging

Abstract

[eng] New treatments for several diseases of young and middle age have increased life expectancy significantly, but as a consequence disorders associated with brain dysfunction are emerging. Even in the absence of brain disorders, aging is related to cognitive deficits, such as memory impairment and motor disabilities that compromise the quality of life. It is generally accepted that oxidative stress, as well as chronic mild inflammation, play a role in the aging process, with the brain being particularly vulnerable to their effects. In this context, one of the main research objectives is the search for strategies or treatments to delay or reduce the effects of brain aging (e.g., the neuroprotective effects of antioxidant natural molecules). In this context, catechins are natural compounds found in fruits and vegetables, especially abundant in some beverages widely consumed around the world for their health benefits due to their antioxidant and anti-inflammatory properties, such as green tea. The neuroprotective properties of catechins associated with sirtuin 1 (SIRT1) protein are revised. This chapter also discusses the role of catechins in molecules vulnerable to oxidative stress that affect brain neurotransmission. Among them, monoamines are neurotransmitters/neuromodulators involved in many functions throughout the brain, such as serotonin, which is a key neurotransmitter influencing hippocampal neurotransmission and memory/learning processes. Monoamine synthesis decreases with age, mainly as a consequence of reduced tryptophan hydroxylase (TPH) and tyrosine hydroxylase (TH) (monoamine synthesis-limiting enzymes) activities due to oxidative damage. In this way, the role of catechins protecting TPH and TH enzymes as well as inhibition of MAO-B enzyme is suggested. In summary, the consumption of catechins or green tea could delay or reverse some manifestations of brain aging; in fact, evidence suggests that they can improve the quality of life of the elderly.