Poria cocos (Fuling) targets TGFβ/Smad7 associated collagen accumulation and enhances Nrf2-antioxidant mechanism to exert anti-skin aging effects in human dermal fibroblasts

Oxidative stress is a major cause of aging related skin injuries. Hydrogen peroxide related ROS accumulation triggers increase in matrix metalloproteinases and elevated collagen degradation, which is a characteristic of skin aging. In this study, we investigated the protective effect of Poria cocos, used widely in the treatment of inflammatory diseases, against H2O2 induced oxidative stress. The aqueous extract of dried P. cocos was obtained by heating 10 g in 500 ml of distilled water. The mixture was evaporated up to 400 ml and the remaining 100 ml was filtered through muslin cloth repeatedly to obtain a clear aqueous extract of the P. cocos. Hs68 human dermal fibroblast cells were challenged with 100 μM of H2O2 for 24 h. Following H2O2 challenge, the cells were treated with increasing concentration of P. cocos extract (100–400 μg/ml) for 24 h. P. cocos extract hindered the H2O2 induced cell death significantly that was correlated with reduction in ROS accumulation. Western blot analysis show that P. cocos extract suppressed the expression of metallomatrix proteinases, inflammatory markers and skin aging markers, but increased TGF-β1 levels and antioxidant related proteins. These data suggest that P. cocos is effective in attenuating oxidative stress associated skin aging effects and may be a potential agent in cosmetics products.