Abstract: Green tea polyphenols (GTP) chemical compositions and metabolic biotransformations were described,and their recent developments in drug discovery,focusing on their chemopreventive and therapeutic effects of cancer,neurodegenerative disease and diabetes.GTPs possess potent anticarcinogenic activities through interfering with the initiation,development and progression phases of cancer.There are several challenges (e.g.,poor bioavailability) in developing GTPs as therapeutic agents.By nanoparticle-based delivery systems has provided unique advantages over purified GTPs.However,there is still a need to determine the actual magnitude and pharmacological mechanisms of GTPs encapsulated in nanoparticles,in order to address newly emerging safety issues associated with the potential ‘local overdose’ effect.