Germacrane Sesquiterpenoids as a New Type of Anticardiac Fibrosis Agent Targeting Transforming Growth Factor β Type I Receptor.
Lou LL, Ni FQ, Chen L, Shaker S, Li W, Wang R, Tang GH, Yin S.
A germacrane sesquiterpenoid library containing 30 compounds (<b>2</b>-<b>31</b>) was constructed by structural modification of a major component aristolactone (<b>1</b>) from the traditional Chinese medicine <i>Aristolochia yunnanensis</i>. Compound <b>11</b> was identified as a promising anticardiac fibrosis agent by systematic screening of this library. <b>11</b> could inhibit the expression of fibronectin (FN), α-smooth muscle actin (α-SMA), and collagens in transforming growth factor β 1 (TGFβ1)-stimulated cardiac fibroblasts at a micromolar level and ameliorate myocardial fibrosis and heart function in abdominal aortic constriction (AAC) rats at 5 mg/kg dose. Mechanistic study revealed that <b>11</b> inhibited the TGFβ/small mother against decapentaplegic (Smad) signaling pathway by targeting TGFβ type I receptor (IC<sub>50</sub> = 14.9 ± 1.6 nM). The structure-activity relationships (SARs) study indicated that the unsaturated γ-lactone ring and oxidation of C-1 were important to the activity. These findings may provide a new type of structural motif for future anticardiac fibrosis drug development.