Pharmaceutical Activities of Theanine: A Phytochemical Nutrient

Theanine, first isolated from tea ( Camellia sinensis (L.) O. Kuntze), has been recognized for its multiple pharmaceutical functions. Typically, theanine is known for its protective effect on neural disorders. In this review, the neuroprotective effects of theanine were summarized in aspects of stress management, cognitive improvement, and reversal of neural injury. Meanwhile, the pharmaceutical functions of theanine in areas such as anti‐inflammatory effects, metabolic intervention, antineoplastic effect, etc., were explored and elucidated. Subsequently, functional expansion, applications for special medical purposes, and clarification of the pharmacological and metabolic mechanism of theanine were proposed as prospects for future research. All in all, identifying more desirable applications and furthering the functional advantages of theanine were the purposes. A systematic understanding of theanine's effect on neural health, as well as the development of theanine‐related products for mental health, would be desired.