Stilbenes are a class of polyphenolic compounds, naturally found in a wide variety of dietary sources such as grapes, berries, peanuts, red wine, and some medicinal plants. There are several well-known stilbenes including trans-resveratrol, pterostilbene, and 3'-hydroxypterostilbene. The core chemical structure of stilbene compounds is 1,2-diphenylethylene. Recently, stilbenes have attracted extensive attention and interest due to their wide range of health-beneficial effects such as anti-inflammation, -carcinogenic, -diabetes, and -dyslipidemia activities. Moreover, accumulating in vitro and in vivo studies have reported that stilbene compounds act as inducers of multiple cell-death pathways such as apoptosis, cell cycle arrest, and autophagy for chemopreventive and chemotherapeutic agents in several types of cancer cells. The aim of this review is to highlight recent molecular findings and biological actions of trans-resveratrol, pterostilbene, and 3'-hydroxypterostilbene.

(−)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to inhibit tumorigenesis and cancer cell growth in animal models. Nevertheless, the dose–response relationship of the inhibitory activity in vivo has not been systematically characterized. The present studies were conducted to address these issues, as well as the involvement of reactive oxygen species (ROS), in the inhibitory action of EGCG in vivo and in vitro . We characterized the inhibitory actions of EGCG against human lung cancer H1299 cells in culture and in xenograft tumors. The growth of tumors was dose dependently inhibited by EGCG at doses of 0.1, 0.3 and 0.5% in the diet. Tumor cell apoptosis and oxidative DNA damage, assessed by the formation of 8-hydroxy-2′-deoxyguanosine (8-OHdG) and phosphorylated histone 2A variant X (γ-H2AX), were dose dependently increased by EGCG treatment. However, the levels of 8-OHdG and γ-H2AX were not changed by the EGCG treatment in host organs. In culture, the growth of viable H1299 cells was dose dependently reduced by EGCG; the estimated concentration that causes 50% inhibition (IC ₅₀ ) (20 μM) was much higher than the IC ₅₀ (0.15 μM) observed in vivo . The action of EGCG was mostly abolished by the presence of superoxide dismutase (SOD) and catalase, which decompose the ROS formed in the culture medium. Treatment with EGCG also caused the generation of intracellular ROS and mitochondrial ROS. Although EGCG is generally considered to be an antioxidant, the present study demonstrates the pro-oxidative activities of EGCG in vivo and in vitro in the described experimental system.

Psoriasis, which is regarded as a T-cell-mediated chronic inflammatory skin disease, is characterized by hyperproliferation and poor differentiation of epidermal keratinocytes. In this study, we aimed to determine the in vivo effect of a potentially probiotic strain, Lactobacillus pentosus GMNL-77, in imiquimod-induced epidermal hyperplasia and psoriasis-like skin inflammation in BALB/c mice. Oral administration of L. pentosus GMNL-77 significantly decreased erythematous scaling lesions. Real-time polymerase chain reaction showed that treatment with L. pentosus GMNL-77 significantly decreased the mRNA levels of proinflammatory cytokines, including tumor necrosis factor-alpha, interleukin (IL)-6, and the IL-23/IL-17A axis-associated cytokines (IL-23, IL-17A/F, and IL-22) in the skin of imiquimod-treated mice. In addition, we found that L. pentosus GMNL-77 decreased the spleen weights of the imiquimod-treated group and reduced the numbers of IL-17- and IL-22-producing CD4+ T cells in the spleen. In conclusion, the present study provides insight into the potential use of L. pentosus GMNL-77 in the future treatment of psoriasis.