Potential Thai medicinal plants for neurodegenerative diseases: A review focusing on the anti-glutamate toxicity effect

Abstract

Neurodegenerative diseases (NDD) are a range of debilitating conditions of the brain involving progressive loss of neurons, many of which are still currently incurable despite enormous efforts on drug discovery and development in the past decade. As NDD is closely linked to old age, the rapid worldwide growth in the aging population contributes to an increasing number of people with one of these incurable diseases and therefore it is considered a significant global health issue. There is an urgent need for novel effective treatments for NDD, and many new research strategies are centered on traditional medicine as an alternative or complementary solution. Several previous findings have suggested that glutamate toxicity drives neurodegeneration in many NDD, and the medicinal plants with anti-glutamate toxicity properties can be potentially used for their treatment. In order to obtain data relating to natural products against glutamate toxicity, six candidate plant species of Thailand were identified. Studies utilizing these herbs were searched for using the herb name (Latin and common names) along with the term "glutamate" in the following databases across all available years: PubMed, Scopus, and Google Scholar. This review emphasizes the importance of glutamate toxicity in NDD and summarizes individual plants and their active constituents with the mechanism of action against glutamate toxicity-mediated neuronal cell death that could be a promising resource for future NDD therapy.

Taxonomy classification by evise: Alzheimer's disease, Neurodegenerative diseases, Cell culture, Molecular Biology, Traditional herbal medicine, Oxidative stress, Glutamate neurotransmitter.

Keywords: Alzheimer’s disease; Glutamate; Herbal medicine; Neuroprotective; Neurotoxicity; Oxidative stress; Plant extract; Traditional medicine.

Graphical abstract

Fig. 1

The biosynthetic pathway of glutamate synthesis and degradation in the human brain.

Fig. 2

The glutamate-glutamine cycle. Diagram of glutamatergic neuron, showing glutamate enclosed in synaptic vesicles, before release and activation of glutamate receptors, and recycling through glial cells.

Fig. 3

Mechanisms of glutamate toxicity in neuronal cells.