Ethyl Acetate Fraction from Hedyotis diffusa plus Scutellaria barbata Exerts Anti-Inflammatory Effects by Regulating miR-155 Expression and JNK Signaling Pathway

Hedyotis diffusa Willd and Scutellaria barbata D. Don (HDSB) were the core couplet in medicines that were commonly used for the purpose of anti-inflammation and anticancer treatments in China. However, biological properties of this couplet have not been fully elucidated. In this study, we screened fractions of HDSB for their anti-inflammatory activities and explored pertinent molecular mechanisms on murine macrophage RAW264.7 cell model. Ethyl acetate fraction from the aqueous extract of the couplet at equal weight ratio (EA11) showed the strongest inhibition of the nitrite accumulation in supernatant of RAW264.7 cells stimulated with lipopolysaccharide (LPS)/interferon-γ (IFN-γ). In addition, EA11 inhibited iNOS and IL-1β expression in a concentration-dependent manner while promoting the expression of HO-1 and PPAR-γ. Anti-inflammatory capability is most likely facilitated by its inhibitory effect on JNK signaling pathway and miR-155 expression. This study suggests that EA11 may be represented as a potential anti-inflammatory therapeutic candidate.