The Anti-inflammatory Effects of Two Ent-kaurane Diterpenes from the Stems and Leaves of Gochnatia decora

Abstract

The Gochnatia decora (Kurz) A. L. Cabrera is a rare woody plant belonging to the family of Asteraceae. The bark of this plant is used as a Chinese folk medicine to treat cough and pneumonia. However, the effective substance related to its efficacy remains unknown. This study aims to evaluate the potential anti-inflammatory activities of the chemicals isolated from this plant using a model of LPS-induced RAW264.7 cells. Chemical constituents were isolated from the stems and leaves of G. decora by a series of chromatographic separation methods and identified by spectral analysis techniques. The model of inflammation in vitro was established by treatment of 1μM LPS on RAW264.7 cells. The influence of tested compounds on inflammatory factor production, including NO, TNF-α, IL-1β, IL-6, IL-17, was determined by ELISA. The mechanisms involved were studied by western blot analysis. Two known ent-kaurane diterpenes (1 and 2), identified as ent-17-hydroxy-15-oxokauran- 19-oic acid (1) and ent-15α-hydroxy-16-kauran-19-oic acid (2), were isolated from the stems and leaves of G. decora. The bioassay showed that both of them produced significant inhibition of LPS-induced release of NO, TNF-α, IL-1β, IL-6, IL-17, iNOS, and COX-2 expression. Western blot analysis showed that these two chemicals blocked LPS-induced phosphorylation of NF-κB. Compounds 1 and 2 were obtained from the genus Gochnatia.These compounds demonstrated useful anti-inflammatory activities in the model of LPS-induced RAW264.7 cells. A potential action mechanism may be the correlation of the NF-κB pathway.