Psoriasis is a chronic inflammatory seronegative disease closely associated with ankylosing spondylitis and inflammatory bowel disease. This study aimed to investigate the anti-inflammatory effects of candidate metabolites, such as D-proline, L-iditol, and propionylcarnitine, identified in Clonorchis sinensis preparations, in in vitro and in vivo models. None of the 3 metabolites exhibited cytotoxicity within the tested concentration range. In LPS-stimulated RAW 264.7 cells, D-proline and L-iditol significantly reduced the expression of pro-inflammatory cytokines, and in an imiquimod-induced psoriasis-like mouse model, L-iditol significantly reduced disease severity and histopathological scores, whereas the effects of other metabolites were inconsistent. These research results suggest that L-iditol, a candidate metabolite identified in Clonorchis sinensis formulations, exhibits anti-inflammatory effects in both in vitro and in vivo environments and may have therapeutic potential for inflammatory skin diseases such as psoriasis.
