Green tea is one of the most popular beverages in the world, especially in Asian countries. Consumption of green tea has been demonstrated to possess many health benefits, which mainly attributed to the main bioactive compound epigallocatechin gallate (EGCG), a flavone-3-ol polyphenol, in green tea. EGCG is mainly absorbed in the intestine, and gut microbiota play a critical role in its metabolism prior to absorption. EGCG exhibits versatile bioactivities, with its anti-cancer effect most attracting due to the cancer preventive effect of green tea consumption, and a great number of studies intensively investigated its anti-cancer effect. In this review, we therefore, first stated the absorption and metabolism process of EGCG, and then summarized its anti-cancer effect in vitro and in vivo, including its manifold anti-cancer actions and mechanisms, especially its anti-cancer stem cell effect, and next highlighted its various molecular targets involved in cancer inhibition. Finally, the anti-cancer effect of EGCG analogs and nanoparticles, as well as the potential cancer promoting effect of EGCG were also discussed. Understanding of the absorption, metabolism, anti-cancer effect and molecular targets of EGCG can be of importance to better utilize it as a chemopreventive and chemotherapeutic agent.

Blueberries possess abundant anthocyanins, which benefit eye health. The purpose of this study was to explore the protective functional role of blueberry anthocyanin extract (BAE) and its predominant constituents, malvidin (Mv), malvidin‐3‐glucoside (Mv‐3‐glc), and malvidin‐3‐galactoside (Mv‐3‐gal), on high glucose‐ (HG‐) induced injury in human retinal capillary endothelial cells (HRCECs). The results showed that BAE, Mv, Mv‐3‐glc, and Mv‐3‐gal enhanced cell viability (P < 0.05 versus the HG group at 24 h); decreased the reactive oxygen species (ROS, P < 0.01 versus the HG group both at 24 and 48 h); and increased the enzyme activity of catalase (CAT) and superoxide dismutase (SOD) (P < 0.05 versus the HG group both at 24 and 48 h). Mv could greatly inhibit HG‐induced Nox4 expression both at 24 and 48 h (P < 0.05), while BAE and Mv‐3‐gal downregulated Nox4 only at 48 h (P < 0.05). Mv, Mv‐3‐glc, and Mv‐3‐gal also changed nitric oxide (NO) levels (P < 0.05). BAE and Mv‐3‐glc also influenced angiogenesis by decreasing the vascular endothelial cell growth factor (VEGF) level and inhibiting Akt pathway (P < 0.05). Moreover, Mv and Mv‐3‐glc inhibited HG‐induced intercellular adhesion molecule‐1 (ICAM‐1, P < 0.001) and nuclear factor‐kappa B (NF‐κB) (P < 0.05). It indicated that blueberry anthocyanins protected HRCECs via antioxidant and anti‐inflammatory mechanisms, which could be promising molecules for the development of nutraceuticals to prevent diabetic retinopathy.

The objective of this research was to survey the antioxidant functional role of the main anthocyanins of blueberries in endothelial cells. Changes on the reactive oxygen species (ROS), xanthine oxidase‐1 (XO‐1), superoxide dismutase (SOD), and heme oxygenase‐1 (HO‐1) in cells of malvidin and the two glycosides were investigated. The results showed that these anthocyanins decreased the levels of ROS and XO‐1 but increased the levels of SOD and HO‐1. Glycosides improved the antioxidant capacity of malvidin to a great extent. The changes in the antioxidant properties of malvidin‐3‐glucoside were more pronounced than malvidin‐3‐galactoside. Variation in levels of malvidin‐3‐glucoside and malvidin‐3‐galactoside had a significant impact on antioxidant properties to different extents. It indicates that blueberries are a good resource of anthocyanins, which can protect cells from oxidative deterioration and use blueberry as a potential functional food to prevent diseases related to oxidative stress.