This study was designed to investigate the hepatoprotective effect of bamboo stems using in vitro and in vivo experimental liver damage models. Ethyl acetate fraction of 80% ethanol extract of Phyllostachys nigra stem (PN3) containing polyphenols had a higher NQO1-ARE reporter gene activity as monitored by the activity of the NF-E2-related factor (Nrf2) antioxidant pathway in cells in comparison to extracts from other species and under other conditions. The Nrf2 was translocated from the cytosol to the nucleus in response to PN3, followed by induction of the Nrf2 target gene expression, including HO-1, GCL, and NQO-1 in HepG2 cells. Phosphorylation of Nrf2 in HepG2 cells was enhanced in PN3, which was mediated by PKCδ, ERK, and p38 MAPK. Consequently, PN3 inhibited arachidonic acid (AA) + iron-induced reactive oxygen species generation and glutathione depletion, and, thus, highlighted their role in cytotoxicity. Treatment with major polyphenols of PN3, including catechin, chlorogenic acid, caffeic acid, and p-coumaric acid, also improved AA + iron-mediated oxidative stress and, thus, improved cell viability. Treatment with phenylhydrazine in mice, i.e., the iron overload liver injury model, increased plasma alanine aminotransferase and aspartate aminotransferase levels and changed histological features in mice—a response that was almost completely blocked by PN3 administration. Moreover, PN3 extract mitigated phenylhydrazine-induced oxidative stress and inflammatory responses. Conclusively, PN3 can exert a hepatoprotective effect against iron overload-induced acute liver damage due to its antioxidant properties.

Ultraviolet B (UVB) rays disrupt the skin by causing photodamage via processes such as reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, DNA damage, and/or collagen degradation. Castanopsis sieboldii is an evergreen tree native to the southern Korean peninsula. Although it is known to have antioxidant and anti-inflammatory effects, its protective effect against photodamage in keratinocytes has not been investigated. Thus, in the present study, we investigated the effect of 70% ethanol extract of C. sieboldii leaf (CSL3) on UVB-mediated skin injuries and elucidated the underlying molecular mechanisms. CSL3 treatment restored the cell viability decreased by UVB irradiation. Moreover, CSL3 significantly inhibited UVB- or tert-butyl hydroperoxide-mediated ROS generation in HaCaT cells. ER stress was inhibited, whereas autophagy was upregulated by CSL3 treatment against UVB irradiation. Additionally, CSL3 increased collagen accumulation and cell migration, which were decreased by UVB exposure. Notably, epigallocatechin gallate, the major component of CSL3, improved the cell viability decreased by UVB irradiation through regulation of ER stress and autophagy. Conclusively, CSL3 may represent a promising therapeutic candidate for the treatment of UVB-induced skin damage.

Nonalcoholic fatty liver disease is the most common chronic disease affecting a wide range of the world’s population and associated with obesity-induced metabolic syndrome. It is possibly emerging as a leading cause of life-threatening liver diseases for which a drug with a specific therapeutic target has not been developed yet. Previously, there have been reports on the benefits of Cudrania tricuspidata (CT) for treating obesity and diabetes via regulation of metabolic processes, such as lipogenesis, lipolysis, and inflammation. In this study, we investigated the ameliorative effect of orally administered 0.25% and 0.5% (w/w) CT mixed with high-fat diet (HFD) to C57BL/6J mice for 7 weeks. It was found that body weight, fat mass, hepatic mass, serum glucose level, and liver cholesterol levels were significantly reduced after CT treatment. In CT-treated HFD-fed mice, the mRNA expression levels of hepatic lipogenic and inflammatory cytokine-related genes were markedly reduced, whereas the expression level of epididymal lipogenic genes was increased. The mRNA expression level of beta-oxidation and Nrf-2/HO-1 genes significantly increased in CT-treated obese mice livers. We propose that CT alleviates hepatic steatosis by reducing oxidative stress and inflammation.