trans-urocanic acid (trans-UCA), a natural epidermal constituent, inhibits human natural killer cell (NK) activity in vitro. trans-urocanic acid is active in regulating an immune function.In Vitro: trans-urocanic acid (trans-UCA) partially inhibits cytotoxic function of IL-2-activated NK cells and reduces IL-2-induced activation of NK cells.
trans-urocanic acid (trans-UCA;100 μg/mL) slightly decreases cell proliferation and viability of primary human keratinocytes[2].