Abstract
Thelephora vialis is a mushroom that grows in symbiosis with pine trees in Yunnan, China, which is known to have some of the richest and most diverse bioresources in the world. T. vialis is a highly prized edible mushroom as it has a special flavor and taste. In our screening for bioactive compounds from in this mushrooms, we isolated a novel potent antioxidant, vialinin A, along with known compounds, from the dry fruiting body of T. vialis. Vialinin A is a terphenyl derivative and was elucidated by spectroscopic and chemical methods. In RBL-2H3 cells, vialinin A showed anti-allergic activities, inhibited the release of β-hexosaminidase, and tumor necrosis factor (TNF-α). Of note, it inhibited TNF-α production from RBL- 2H3 cells more strongly than tacrolimus, which is used as an immunosuppressant in organ transplantation (halfmaximal inhibitory concentrations: 0.09 nM and 0.25 nM, respectively). In addition, ubiquitin-specific peptidase 5, a deubiqutinating enzyme, was identified as a target molecule of vialinin A and its enzymatic activity was inhibited by vialinin A. The potent inhibitory activity of vialinin A against TNF-α production indicates that it is a promising candidate as a new anti-allergic agent.
