In many countries, including Asian countries such as Japan, Singapore and
Thailand, aging populations have been increasing, thus promoting a high risk for ageassociated
chronic diseases. One of the devastating chronic diseases in people with old
age known to greatly impact the patients’ quality of life is a group of
neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. It has
been evident that neurotoxicity is a significant risk of neurodegenerative disorders. One
of the crucial contributing factors leading to neurotoxicity in humans is glutamate, the
excitatory neurotransmitter. If it is accumulated in the brain, this neurotransmitter can
result in neurotoxicity via either glutamate-dependent pathway or glutamateindependent
pathway. Glutamate neurotoxicity (GNT) is characterized by rising
damage of cell components leading to cell death. In the death process due to oxidative
stress, reactive oxygen species (ROS) are generated, thus impairing a vast array of
cellular functions in many organelles such as mitochondria and endoplasmic reticulum.
GNT has been clearly observed in the brain tissue because of the accumulation of
glutamate, not only from the endogenous source, but also the exogenous source such as
monosodium glutamate. Fortunately, numerous plant extracts and their chemical
constituents, particularly the ones with high anti-oxidant activity, have been found to
exhibit anti-GNT in both vitro and in vivo models. Herein, mechanisms of anti-GNT of
botanicals and their chemical constituents are presented and discussed in detail. Their
anti-GNT mechanisms elucidated could shed light on the discovery and application of
neutraceuticals, and the cell defense mechanisms of natural neuroprotectants could
certainly be beneficial to improve both healthspan and lifespan in humans.
Keywords: Glutamate neurotoxicity, Natural products, Neuroprotectants,
Neutraceuticals, Reactive oxygen species.
