In vitro inhibitory effects of cirsiliol on IL-6-induced STAT3 activation through anti-inflammatory activity

Many studies have identified and described various medicinal effects of cirsiliol. Here, we investigated the signaling pathway involved in the anti-inflammatory effects of cirsiliol on IL-6-induced activity. Cirsiliol showed no cytotoxicity and inhibited pSTAT3-induced luciferase activity. At the molecular level, cirsiliol suppressed the expression of IL-6-induced inflammatory marker genes such as CRP, IL-1β, ICAM-1 and SOCS3, IL-6-induced activation of Jak2, gp130, STAT3 and ERK and nuclear translocation of STAT3, as measured by PCR, immunofluorescence staining and western blot analysis. However, the interaction between IL-6 and its receptor was not affected by cirsiliol treatment. These results indicate that cirsiliol attenuates IL-6-induced cellular signaling by regulating Jak2 phosphorylation. Therefore, cirsiliol could be a therapeutic agent for IL-6-related inflammatory diseases.