Research on the anti-hepatic fibrosis effects and active components of the medicinal plant Tithonia diversifolia.

Background: The medicinal folk plant Tithonia diversifolia A. Gray has traditionally been used to treat hepatitis and liver cancer. However, the anti-fibrotic effect of this plant extract and its main active substances remain unclear.

Objective: This study aims to elucidate the anti-fibrotic effect of T. diversifolia ethanol extract, identify the main active substances, and explore their possible molecular mechanisms.

Methods: Firstly, carbon tetrachloride (CCl₄) was injected intraperitoneally to induce liver fibrosis in mice to investigate the protective effect of T. diversifolia ethanol extract. Then, thirty compounds in this extract were identified through liquid chromatography-mass spectrometry (LC-MS/MS) analysis, column chromatography, and spectroscopic analysis. In addition, the anti-fibrotic effect of sesquiterpene lactone compounds were investigated on TGF-β-induced hepatic stellate cell activation.

Results: The T. diversifolia ethanol extract significantly inhibits symptoms of carbon tetrachloride-induced liver fibrosis and the collagen deposition in pathological tissues by suppressing the protein expression of various pro-fibrotic factors. A comprehensive profile of thirty-one compounds was established, including nine sesquiterpenes, six phenolic acids, six fatty acids, five phenylpropanoids, and three flavonoids. Notably, one previously unreported sesquiterpene lactone, namely 1β-ethoxydiversifolin 3-O-methyl ether (1), together with twenty-nine known compounds were obatined. Sesquiterpene Tagitinin C shows significant anti-fibrotic effects on TGFβ1-induced HSC-T6 activation by inducing cell apoptosis and regulating the TGF-β1/Smad pathway.

Conclusion: The above results indicate that the T. diversifolia extract can effectively alleviate liver fibrosis, with sesquiterpene lactones being a major component. In the future, the germacranolides-type of sesquiterpene lactone Tagitinin C can be developed as a precursor compound for anti-fibrotic therapy.