A Water-Soluble Extract from Actinidia arguta Ameliorates Psoriasis-Like Skin Inflammation in Mice by Inhibition of Neutrophil Infiltration

Psoriasis is a chronic inflammatory disease with complex etiology involving multiple factors. Current treatment methods are highly limited and there is a strong need for the development of safer and efficacious agents. We have previously shown that a water-soluble extract derived from hardy kiwifruit Actinidia arguta, called PG102, shows potent anti-inflammatory effects. Based on its reported biological activities, the effects of PG102 were examined on imiquimod-induced psoriasis-like skin inflammation. Our results showed that topical application of PG102 ameliorates clinical symptoms of psoriasis, reducing skin thickness and Interleukin (IL)-17A level in draining lymph nodes without causing any adverse effects. Treatment with PG102 on cytokine-stimulated HaCaT cells suppressed hyperproliferation and downregulated the expression of various chemokines and antimicrobial peptides known to induce neutrophil infiltration. These anti-inflammatory activities of PG102 were mediated via inhibition of NF-κB and signal transducer of activation (STAT) signaling. We also found decreased neutrophil chemotaxis both in vitro and in vivo. Taken together, PG102 has potential as a safe and effective reagent for the treatment of psoriasis.