Anti-apoptotic effects of phyllanthin against alcoholinduced liver cell death

Purpose: To evaluate the anti-apoptotic effect of phyllanthin on alcohol-induced liver cell death in HepG2 cells alone and in co-culture with human monocytic (THP-1) differentiated macrophage cells. Methods: Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cells were pretreated with 1, 5 and 10 μM phyllanthin for 24 h followed by 1300 mM alcohol for HepG2 cells and 2000 mM alcohol for the co-cultured cells. Thereafter, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP) changes, apoptotic cell death and caspase-3/7 activities were assessed. Results: Alcohol exposure significantly increased intracellular ROS generation (p < 0.001), decreased MMP changes (p < 0.001), increased the number of apoptotic and necrotic cells (p < 0.001) and also induced higher caspase-3/7 activity (p < 0.001) in the co-culture with THP-1 differentiated macrophage cells than in HepG2 cells alone. Pretreatment of HepG2 cells and co-cultured cells with phyllanthin for 24 h prior to alcohol exposure significantly decreased intracellular production of ROS (p < 0.001) and also increased the change in MMP (p < 0.001) as well as caused a decrease in the number of apoptotic and necrotic cells (p < 0.001), but inhibited caspase-3/7 activity (p < 0.001). Conclusion: The results indicate that phyllanthin treatment may have a significant therapeutic effect on alcohol-related liver diseases.

Natural plant polyphenols for alleviating oxidative damage in man: Current status and future perspectives

The balance between oxidation and reduction is important for maintaining a healthy biological system. Oxidative stress results from an imbalance between excessive formation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS) and limited endogenous defense systems, and this imbalance can adversely alter lipids, proteins and DNA, causing a number of human diseases. Thus, exogenous antioxidants that can neutralize the effect of free radicals are needed to diminish the cumulative effects of oxidative damage over human life span. Current research reveals that phenolic compounds in plants possess high antioxidant activity and free radical scavenging capacity and can prevent the body from oxidative damage over human life span. This review focuses on the present understanding of free radicals and antioxidants and their importance in human health and disease. Information about the chemical features of free radicals as well as their deleterious effects on cell structures is reviewed. The chemical structure and anti-oxidative mechanisms of essential polyphenols and their potential health benefits are presented. In addition, the limitation of natural antioxidants and a perspective on likely future trends in this field are also discussed.