Nanotechnological approaches to enhance the bioavailability and therapeutic efficacy of green tea polyphenols

Green tea contains numerous bioactive compounds that may provide multiple health benefits, including antioxidative, anti-inflammatory, anti-carcinogenic, anti-proliferative, anti-hypertensive, antithrombogenic and lipid-lowering effects. Most of the chemopreventive and therapeutic effects of green tea extracts have been attributed to the presence of different polyphenolic bioactives, especially catechins, in their composition. Although these polyphenolic compounds have been shown promising therapeutic effects under in vitro conditions, they met with limited efficacy in clinical settings due to various reasons such as poor oral absorption and bioavailability. Different techniques have been proposed to improve the bioavailability of green tea polyphenols. Among such strategies, nanoparticle-based delivery systems are novel and promising tools. This review is intended to discuss the advances related to improvement of in vitro and in vivo bioavailability of green tea polyphenols using nanotechnological approaches, which in turn would aid in enhancing their therapeutic efficacy.