Application of EGCG as a Neuroprotective Agent for the Treatment of Neurodegenerative Diseases: A Review Article

Background and Objective: Neurodegenerative diseases are a major public health challenge with a great socioeconomic burden on society. Unfortunately, to date, there is no definitive treatment for neurodegenerative diseases and new drug developments and therapeutic strategies remain urgent and important requirements. In this regard, medicinal plants and their active ingredients are very invaluable in the discovery and development of new drugs for these diseases. Accordingly, we reviewed epigallocatechin gallate (EGCG) for neuroprotective effects. EGCG, the main active ingredient of green tea (Camellia sinensis) has shown different pharmacological properties, such as anti-inflammatory, antioxidant, and free radical scavenger effects. Considering the various pharmacological roles of EGCG involved in the pathophysiology of these diseases, the objective of this study was to review the effects of EGCG as a new therapeutic potential for the development of new drugs for the treatment of neurodegenerative diseases Search method: Related studies were searched in the Google Scholar and Web of Science databases. In order to find related studies Scopus and PubMed databases were also searched. The following keywords and terms were applied: "neurodegenerative diseases and EGCG", " neuroprotective effects and EGCG " , " epigallocatechin gallate, and neuroprotective " . After deleting irrelevant articles, the relevant articles were selected. No limitation for the year of publication was applied in the search. Findings : The results of clinical studies, including a study conducted in Japan by Shinichi Kuriyama and coworkers showed that EGCG is effective in reducing the incidence of cognitive impairment. In addition to this study, during a ۲۰-year cohort study with ۱۳۰,۰۰۰ participants, it was shown that EGCG consumption was associated with a ۴۰% reduction in the incidence of Parkinson's disease in the community. Furthermore, the in vitro study showed that EGCG has protective properties against beta-amyloid toxicity in Alzheimer's disease. The findings of this review study indicated that the neuroprotective properties of EGCG are due to various mechanisms such as antioxidant properties, free radical scavenging, reduction of apoptotic markers, reduction of inflammation in the brain, prevention of Hydroxydopamine toxicity, and reduction of neuronal damage. But this substance has been shown to provide low bioavailability and low efficacy through oral administration. Numerous preclinical studies have been performed on the use of new drug delivery systems to increase the therapeutic effect of EGCG in various diseases, including cancer. However, studies on increasing drug delivery in neurodegenerative diseases are still limited and further studies should be conducted. Conclusion: Due to the neuroprotective properties of EGCG observed in various studies, it can be suggested as a potential treatment for neurodegenerative conditions by launching further studies in the field of pharmacokinetics and benefiting from new drug delivery systems. In addition, conducting more laboratory studies and understanding the cellular-molecular mechanisms of effects shown by EGCG may provide suitable basis for novel drug development for disabling neurodegenerative diseases in future.

Keywords:

neuroprotective , epigallocatechin gallate , neurodegenerative diseases , green tea